Poll
Yeah. I get cut off at least once a week at a double protected left/right because people either turn into the other lane or cross the dividing line while making the turn. People don't understand how to be safe in protected left turns. Why add more dangerous elements?
That might be a regional thing. Like basically any traffic control device, there are parts of the country where it works better than others. There are more than a few double left turns near me, and I really can't recall being cut off before. As long as the lane lines are delineated well throughout the intersection, I don't think it's as big of a problem as it may appear to be.
I'm going by how people drive on dual left turns in the midwest. I've seen too many accidents happen due to people leaving their lane while turning.
But wouldn't everyone just stay in the lane that permits turns? You'd have a pretty uneven lane balance I'd think.
A pretty common scenario with permissive turns, number of lanes irrelevant, is having the FYA go red when the pedestrian walk signal is green (Bellevue, WA does this at many of their FYAs). This might solve that problem.
That's what happens here with dual right turns. Everyone who lives around here knows that more than 99% of the time there'll be a sign prohibiting right on red from anywhere but the far right lane, so almost everyone will use only the far right lane unless the light is already green.
(I say "more than 99% of the time" because I can readily think of one light that doesn't have this restriction posted–the dual right turn from westbound Huntington Avenue to northbound Telegraph Road just south of the Beltway. Also, oddly, where there are dual left-turn lanes and a left-on-red situation, I've never seen a sign restricting lefts on red to the far left lane, although I have seen a "No Turn on Red" sign at a left-on-red spot.)
The low compliance rate among pedestrians can make this type of setup more harmful then helpful. It's conditioning drivers not to look for pedestrians during the permissive phase even though pedestrians may very well be present (since a pedestrian may simply chose not to push the pushbutton). There is a 2001 study from Windsor, Ontario where the pushbutton was actuated in only 32% of the cycles where a pedestrian crossed the street.
I don't think I've ever seen this... It also seems that the capacity of the PPLT would be reduced considerably in such a case where this is done.
Sorry, should have been more specific. I have witnessed this in Bellevue, WA.
One of Bellevue's engineers, Mark Poch, gave a presentation a few years ago, and there's a snippet from that powerpoint, which I have seen many times implemented in Bellevue, which suggests eliminating the permissive phase during walk signals:
Here's the whole presentation: http://goo.gl/sqg5qV. Page 19 has that quote on it, followed by a bunch of examples.
Exact data? Not really much. But the Virginia DOT (I cited this earlier) collected statements (http://goo.gl/jQObb5) from different agencies about their experiences with flashing yellow arrows, and some of them noted their uses with double permissive lefts:
Kennewick, Washington:
Boulder, Colorado:
Richardson, Texas (by way of Las Vegas):
The quotes start on page 64 according to the PDF, though the page number on the bottom is 25.
There's one near my house in Gwinnett County, GA (https://www.google.com/maps/@33.9553145,-84.0567781,3a,75y,42.57h,78.28t/data=!3m6!1e1!3m4!1sp2dOn2RfYlSyvAAlqPFRSg!2e0!7i13312!8i6656). It's an anomaly, AFAIK, but it's been like this for decades, even as FYA's have started to appear nearby. I hope it remains as is-- I've never had a problem with it. I guess that's mainly because straight-through traffic between Cruse Road and Marathon Blvd is very light.
In the south suburbs of Chicago, the dotted line indicating where to turn is usually ignored. The drivers in the outer lane frequently tend to cross it, varying from just half a tire width to the entire car being inside the curve. They often don't allow the inner lane enough room and it often leads to the inner cars either hitting the median or causing the end of the turn to be extra sharp. I will not use the left/inner lane of a double left anymore because it has become that bad.
It extends east to at least Buffalo (which may as well be considered the Midwest). I see that every day. That or people on the inside take it too wide. Quite often, you'll have people on the inside making their turn so they end on the outside.
I know living in Orlando, the most dangerous intersections are the ones with the protected lefts. Everyday, I see people running the red lights because they don't want to have to wait another 4 minutes to make their turn. The permissive signals eliminate that anxiety and fear as there is a chance they can make the turn sooner. I know thats my reaction... if its turning red, rush through the light, if its going permissive, I can wait as I can go in a gap in traffic and won't have to wait for every other phase of the cycle.
I don't think that's necessarily the same thing (although they are related).
Those are protected by default because there is no oncoming traffic and no pedestrians. Isn't the same.
They're replacing it with a protected phase. Oh, well, it was nice while it lasted. :no:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FEru4V6b.jpg%3F1&hash=c41d268ce0477a0cf5b2634a21fdb09b76fc1a7b)
Is that a permitted left though? Looks like it could be a split phase setup just using 5-aspect heads, due to the shared lane... In street view, it only shows as either red or green arrow+ball (with red for opposing traffic) in all time views, so this seems like a split phase.
If it is a permitted setup, that's rarely a good idea to have a protected/permitted left with a shared lane...that can hinder throughput.
MUTCD actually prohibits using a shared left turn lane for a dual left if it isn't split phasing. Of course, you get places like the Adirondacks (https://www.google.com/maps/@43.3296972,-73.6849764,3a,22.4y,264.79h,84.06t/data=!3m6!1e1!3m4!1sMPd-l5CgBsMpr4iYbgaBNg!2e0!7i13312!8i6656) which violate this, but the installation posted in this thread may date to before the restriction was put in place.
It's very much a permitted setup with a green for the other direction. I've been through it many, many times, but it's never all that busy.
Does the signal ever display the green ball alone without the arrow? I didn't see evidence of this in Street View.
Yes, it does. There's not usually a lot of traffic coming from the other direction, but it does have the green without the arrow.
Both of those lanes are permissive, and the signal dates to at least the 1970s like that.
I think the dual permissive lefts work better with flashing yellow arrows. Not sure why. Glad Minnesota's DOT doesn't outright ban their use (engineering judgement permits any sort of signal combination -- :thumbsup:).
Interesting that the road wasn't scaled back after the 71 freeway was finished. Pretty cool nonetheless. I think this might be unique in being the only dual permissive left that has no protected phase.
Those left-turn signal heads should be bagged during construction.
If you look carefully, the individual lights have been gift-wrapped.
Nope, here's another one not far from where I live.
https://www.google.com/maps/@41.5036083,-87.4714439,3a,75y,96.18h,75.06t/data=!3m6!1e1!3m4!1sBgz-MViN_o5JHW7SF88lsw!2e0!7i13312!8i6656!6m1!1e1
Yeah, I had to zoom in pretty close to determine what happened. If you look real carefully, you can see the red light is lit underneath the bag.
Here's somewhat of a similar situation: https://goo.gl/maps/2UHbNjsBQND2 . Train lights look like they're in use. But when you look real close, you see bags are covering the lights. https://goo.gl/maps/cAgUzNKoMLM2 Oh...there's no tracks either! https://goo.gl/maps/qDEzsgMLnsF2
Nope. The baby half-SPUI at the VT 9/279 intersection is protected, as is every SPUI in New York and every one I know of in Ohio.
Southbound Kirby Rd to TN 385 eastbound in Memphis used to have a permissive doghouse signal for a while (a year or two) after it went on a diet from two left turn lanes to one, but it's now back to a protected-only signal. As far as I know, that's the only permissive signal ever installed at one of 385's SPUIs.
There's slightly more of the permissive dual lefts in Chicagoland than triple lefts. There's also:
* Thorndale Avenue at Park Avenue in Itasca (until IL 390 is finished), with permissive dual lefts for both eastbound and southbound: Streetview (https://www.google.com/maps/@41.983587,-88.012649,3a,75y,48.72h,83.24t/data=!3m6!1e1!3m4!1se3kb1mlubxpoqlPnZfA2pg!2e0!7i13312!8i6656?hl=en) (DuPage County's jurisdiction)
* Sunset Ridge Road at Skokie Boulevard in Northbrook (IIRC under Cook County's jurisdiction) Streetview (https://www.google.com/maps/@42.1345179,-87.7897059,3a,75y,68.43h,76.69t/data=!3m6!1e1!3m4!1sL2Jx2eiEIiEJ-JQWs37JLQ!2e0!7i13312!8i6656?hl=en)
I think there is one more in Chicagoland that I can't place as of this typing.
As for single point interchanges with permissive left turns:
* Grand Avenue at the Amstutz Expressway/IL 137 in Waukegan (probably doesn't count since the ramps are controlled by stop signs) Streetview (https://www.google.com/maps/@42.3638835,-87.8285108,3a,75y,230.63h,82.68t/data=!3m7!1e1!3m5!1sTT3_EDjHZD-nLaCDQEkCWA!2e0!6s%2F%2Fgeo3.ggpht.com%2Fcbk%3Fpanoid%3DTT3_EDjHZD-nLaCDQEkCWA%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D41.986012%26pitch%3D0!7i13312!8i6656?hl=en)
* Nebraska Highway 2 at US 77 in Lincoln (Streetview (https://www.google.com/maps/@40.7876137,-96.7298594,3a,81.4y,252.68h,87.86t/data=!3m7!1e1!3m5!1sBUn-HM1JOzV-sZd6r5xBcA!2e0!6s%2F%2Fgeo3.ggpht.com%2Fcbk%3Fpanoid%3DBUn-HM1JOzV-sZd6r5xBcA%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D237.67863%26pitch%3D0!7i3328!8i1664?hl=en))
As for the poll in this thread: Yes, I think permissive dual lefts should be allowable, especially when they are across an opposing through movement with a low volume. Missouri has it in their manual that with engineering judgement, a dual left across a single opposing through can be used (see about halfway down the page here). (http://epg.modot.org/index.php?title=902.5_Traffic_Control_Signal_Features_%28MUTCD_Chapter_4D%29)
I almost wrote a sentence about excluding the Amstutz stop signs, but I figured I'd wait to see if anyone would bring them up. Didn't think it would be reply #2!
There's another permissive SPUI in Billings, Montana. Mullowney Lane at I-90 (streetview (https://goo.gl/CFlA7J)):
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FyHQ0zIX.png&hash=9cf76e951b2b837ec366b3b33668942fd4eb0cc6)
Slightly related: can anyone think of any reason why nearly all single-lane SPUIs are protected? Sometimes permissive turns are disallowed because of overlap, but SPUIs are designed to run with opposing left turns. If anything, they're built for permissive signals! I get why the majority are protected-only (most are dual turns, which are almost always protected), but the single-lane SPUIs would be great candidates for permissive signals.
My guess would be the intersection geometry, SPUIs tend to be on the larger side and have very wide sweeping left turns. This would make it take longer for turning vehicles to clear the opposing lanes and reduce the acceptable gap to the point where it could be too difficult to judge. I'd also imagine that SPUIs are normally built at busy locations with high enough turning movements to justify fully-protected phasing.
Split-phased should not count as permissive, because those are always protected. It just happens to be that the protected left turn phase is equal to the straight-through traffic phase.
Well of course they aren't permissive. I was trying to say that the signals, in several of the street view images, appear to be split phased, but when you click around, you can see that they are not. Several of South Africa's multi-lane permissive right turns have the second or third right turn lane as an option lane, so you'd think they'd be split phased.
This perceived danger (vehicles changing lanes during a turn) seems to be the biggest fear among those who oppose dual permissive turns. My thought is this: are vehicles changing lanes during the permissive phase more often than during the protected phase?
Visibility really should be the argument against dual permissive turns. From studying the various dual turn lanes around the world, I've come up with two solutions to this issue:
1) Offset the dual turn lanes whenever possible. This requires slightly more ROW, but the cities that use this style seem to report fewer issues. Tucson is the best example. Note the chevrons between the left turn lanes and the through lanes. The FHWA's "Signalized Intersections: Informational Guide (https://goo.gl/31JHVM)" has a couple pages dedicated to Tucson's offset dual turns lanes, and notes a "potential issue is sight distance for the left-turning vehicles", and that "[t]he City of Tucson addresses this concern by offsetting the far lane by 1.2 to 1.5 m (4 to 5 ft) so that it has the same sight distance as a single left-turn lane" (PDF pg 338).
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FCajNWg0.png&hash=d5c73070660017d39535b614371332857809aefa)
2) Use secondary stop lines. These are almost unheard of in the US. They seem to be used more often in Europe, but more important to this conversation, South Africa has several dual permissive turn lanes with these secondary stop lines. In cities with drivers who pull pretty far forward into the intersection (cool with a single turn lane, but a little annoying with two turn lanes), this helps prevent the inside lane from being totally blind. As well, cities with more hesitant drivers will be more apt to pull forward to wait to turn, which helps with throughput. Because this secondary stop line is more of a "yield line", I'd recommend using sharks teeth, instead of the broken white lines used in South Africa:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FxRWAhR3.png&hash=0d34127525497676ed9f0e1f7f4eb40f4537d635)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F0Ce1Pwk.png&hash=634670ce4aade738b0de9b4ebbc0688e141ebcca)
That's a great point. With lagging left turns drivers have an opportunity to clear the intersection at the end of the thru phase. Permissive dual left turns are somewhat more acceptable if drivers are guaranteed a protected left at the end of the thru phase.
But why? Is there any evidence to suggest that Tucson needs to do away with their permissive dual left turns? Tucson's website (https://goo.gl/cNbCb3) is highly protective of the permissive phase:
On leading vs lagging signals, with the advent of flashing yellow arrows, protected/permissive left turns should begin with the permissive phase. If there's only one car, they'll get through either in the middle of the cycle, or at the end. And if several more cars show up to turn left, the lagging protected left turn will be able to get the rest of them through the intersection, rather than making them wait for the next leading left turn, which would be after the cross-traffic gets their phase.
My point being, Tucson is pretty ingenious, having adopted lagging pro/per signals. Though I'd like to see them transition over to FYAs, so there isn't a red phase in the middle of the left turns.
R1 only uses the staggered phasing if it's fully-protected. PPLT gets leading if both directions, either lagging or leading if one direction.
That's a Canada thing. I can't honestly say I've ever seen a red arrow in BC before. Can't speak for the rest of the provinces, though I don't recall seeing any in Alberta last I was there.
Sorry to bring up such an old quote, but I need some clarification. When you said "permissive" in the first two sentences, did you mean "protected"? It makes more sense with the word "protected", especially since you brought up Region 1's lagging phasing immediately after:
Not unlike Illinois which requires two (minimum) signals per turning direction and three (minimum) for through traffic.
An example with permitted lefts (IDOT District 3): https://goo.gl/maps/5qq6x6dJKjo
An example with protected only lefts (IDOT District 1): https://goo.gl/maps/kXSRrhtd5iL2
I've noticed that Illinois uses a lot of overhead stop-line signals (when five-section signals are involved). Can't say I'm a huge fan of this practice (I prefer post-mounted stop line signals, which I think are more common in Illinois anyways), but at least there's more than one signal, unlike out here in Washington and Oregon, where you're lucky to have more than one signal for turning movements (hence my preference for the BC standard).
From my experience, these places have the best signals:
- British Columbia (+1 for three pole-mounted protected left turns)
- California (-1 for their propensity to use protected lefts, but +1 for near-side pole mounted signals for through movements)
- Tucson, AZ (+1 for dual permissive lefts and near-side pole-mounted signals)
- Illinois (-1 when near-side overhead signals are used)
- Wisconsin (+1 for near-side pole mounted signals at nearly every junction)
- Colorado (+1 for overhead signals using backplates but not side-mounted signals -- I think this looks better and makes the mast-arms less bulky).
Whoops. Yes I meant "mast". Thanks for filling me in.
While not an expert on MD per se, I am very familiar with this intersection as I drive by frequently.
I can say that this an exception as I cannot think of other permissive double lefts in MD anywhere. One factor how this may be safer than others is that this is a
T intersection. There is no corresponding left turn in the opposite direction, and you don't have to worry about cross traffic or right turns or anything. So if there are other dual left turn FRAs, they would only be in similar circumstances (on-ramp to freeway) and not a standard intersection.
FWIW, the visibility here is excellent. It is very easy to see SB traffic when making the left turn from NB NH ave to US 29 (from either lane). I believe before 2005, there was no traffic signal at all and for most hours of the day, except rush hour a singal was not needed. It seemed that there was enough of a backup during rush hours that they felt that a second lane was necessary and still provided an option for a protected signal. I give DOT a lot of credit for making this protected/permissive.
The normal operation of the signal is SB green and NB FRA. When there are enough who want to make the left, the SB signal goes from yellow to red. After a brief period NB left becomes a green arrow, then a yellow arrow, and then a solid red arrow for a few seconds while SB traffic is released with a green. And then FRA again.
I'm really, really glad to hear these work well. Anybody who knows me, knows I really like permissive double lefts (mostly because I don't like protected lefts, period). Maryland's approach seems like a really good middle ground between flashing yellow, and protected-only. Particularly at Parclo B4s (such as in the Silver Spring example), where the only signalised movement is a left turn, they seem like a great candidate for FRAs (though only if the left is a double left -- I still prefer FYAs at single left turns.
As for the phasing, I'd have thought that going from FRA to green arrow would be acceptable (FRA to solid yellow seems a bit odd). But if the phasing described above is what Maryland has more success with, more power to them.
I may not have been clear in my last post about the signaling. Hopefully this is better:
NB: SB:
FRA Green
FRA Yellow
FRA Red (one second)
green arrow Red
yellow arrow red
solid red arrow red (one second)
solid red arrow green (15 seconds)
FRA green
There is a brief period, about 15 seconds, when SB traffic is first released on the green that NB traffic may not turn left (solid red arrow).
There is no interval from FRA to yellow arrow. There is no indication from the NB side that SB gets a yellow ball. You sit at the intersection waiting to make a left and you may notice that some of the cars that are approaching SB are slowing or stopping. By the time you realize that the opposing side has a red, the green arrow comes on and you can go.
Of course NB thru traffic faces no signal whatsoever and is functionally equivalent to a continuous green.
I did misunderstand what you wrote. That you for the clarification. I got the SB and NB phasings mixed up.
The 5-section is the standard permissive signal in New York City. Another type is a 2-section 12" arrow face alongside a 3-section 8" face. I don't think there's a single doghouse inside the City.
Having family nearby until relatively recently, this was the only dual-permissive left turn installation I knew of anywhere until I was almost 9. It's still one of the less than 5 I have seen in person. I'm convinced that this was only done because opposing turns are prohibited and sightlines are wide-open. I do NOT know of another dual permissive left in New York that has opposing left turns (excluding the east end of Queens Blvd (https://www.google.com/maps/@40.7043938,-73.8154668,3a,75y,150.56h,77.42t/data=!3m6!1e1!3m4!1s_py5QYyiWGRB1Q4-xP_OzQ!2e0!7i13312!8i6656), which has open sightlines due to the way the WB ROW shifts).
There's a permissive dual option lane in NYC at Centre and Chambers on the Manhattan side off the Brooklyn Bridge:
https://www.google.com/maps/@40.7129151,-74.0042291,3a,75y,50.72h,79.23t/data=!3m6!1e1!3m4!1s5-CrH0LbXNFXaQhzIN7_nA!2e0!7i13312!8i6656
This is the only doghouse proper in NYC (excluding the airports which have signals maintained by PANYNJ), which also happens to be one of the few spanwire signals in NYC
Arthur Kill Rd, Staten Island
https://goo.gl/maps/6UPjSZra8nv
This setup by Queens Center Mall (https://goo.gl/maps/23Dn3y7yMcN2) is technically a dual permissive left, but left is the only way to go here. The signal sequence is
Red ball Green arrow -> Red ball Yellow arrow -> red ball -> green ball (opposing traffic gets a green and pedestrians get walk signs) -> yellow ball in both directions -> red ball in both directions
Flashing yellow arrows would do better here IMO since drivers must yield on the green ball phase and there is high pedestrian and opposing traffic.
There are also quite a few permissive left turn / left turn+thru option lane setups in NYC. Two that i know of are 108 st/ LIE service road (https://goo.gl/maps/buNmkTCsNQL2)(lagging left in both directions, lanes are a bit hard to see in streetview), and Junction Blvd s/b at the LIE (https://goo.gl/maps/Weg7bzQJGk72) (lagging left)
Very interesting, typically I associate Denmark with separated protected left turns, like this (https://www.google.com/maps/@55.6710258,12.4554156,3a,25.8y,81.7h,86.47t/data=!3m6!1e1!3m4!1sGuzv7g0XDZlpo5O9BCAqsg!2e0!7i13312!8i6656) or this (https://www.google.com/maps/@55.6706014,12.4565737,3a,41y,351.99h,85.14t/data=!3m6!1e1!3m4!1s2usvwLlqtHTcQyAG8GsH_Q!2e0!7i13312!8i6656) (semi-protected). I've dubbed them "Danish turn lane" due to their tendency to separate them by wide paint or a barrier, something I rarely see in Sweden.
As for as I know, there are no dual permissive left turns in Sweden. At speeds >50 km/h signal regulated permissive turns are not allowed, but must use a left turn arrow instead, and dual turn lanes are quite uncommon in cities, and when they exist I'm pretty sure they're all protected turns. I've come across some regulations related to left turns, but it seems the closest we have to permissive left turns are dual left turns using circular lights with no oncoming traffic. Translated below for reference.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FhoUE0uZ.png&hash=0477f5b5949540a500f2b300aedab972267a7b0b)
I also noticed this while browsing around. In particular, the primary roads have left turn lanes separated by either a barrier or paint, but the side roads have everything smushed together (with a barrier only between opposing directions), like in the image above. I wasn't able to find any double permissive turns from a primary road, but several from a side street (that would otherwise have a yield sign). Here's one with a option lane: https://goo.gl/gTNQ7n (no visible red arrow signals, so I assume it's a permissive left).
Dual turn lanes are also uncommon in the UK. Seems like older places just don't have the room for them.
So it looks like "split phasing" is used at these option-lane left turns?
Interesting that 50 km/h is the maximum for permissive lefts. Some states have limits on permissive lefts (usually speed limit ≤ 70 km/h), but I'm unaware of a state with a 50 km/h limit (though that's just for the state -- individual cities are free to do as they wish). 50 km/h seems kind of low to me.
Aviation Parkway in Tucson, Arizona is a 90 km/h road with permissive lefts: https://goo.gl/KxGp3E. Very few roads with this high of a limit have signals in the US, so this must be one of the highest posted roads with permissive lefts.
I wouldn't say it's uncommon to see signals or permissive lefts on a road posted at 55 mph (90 km/h), definitely not in the northeast and midwest. Ohio allows signalized at-grades on roads posted up to 60 (mostly protected, but I have seen a couple permissive) and unsignalized at-grades up to 70. New Jersey divided highways are often 55, signals or "Jersey Freeway". Default for New York is 55 (co-posted as 90 km/h in a couple places) and it doesn't go down for signals. NY's 55 roads generally have permissive lefts.
After doing a bit of research, it appears that my comment was (a bit) unfounded. :pan: Even Washington has several high speed roads with permissive lefts. I guess I forgot about them.
In Utah, a protected left is required if the speed limit is 60 or higher, and protected lefts are required for dual left turn lanes. https://www.udot.utah.gov/main/uconowner.gf?n=22168023889671869 (https://www.udot.utah.gov/main/uconowner.gf?n=22168023889671869)
Outside of cities we tend to favor this type of offset junction (https://www.google.se/maps/@58.293344,15.8936128,3a,39.2y,149.27h,83.22t/data=!3m6!1e1!3m4!1s6mhgcW7vxiAkZTfxH9D8Eg!2e0!7i13312!8i6656). Traffic volumes are rarely a problem here, so signals outside of city limits are very rare. I know of one that sort of counts (https://www.google.se/maps/@58.9816552,14.6234923,3a,49y,59.24h,84.16t/data=!3m7!1e1!3m5!1szst2HcMSGG5MT1zygCOYxw!2e0!5s20100901T000000!7i13312!8i6656), now replaced by a roundabout.
I've seen studies that show permissive signals to be safer than protected-only signals, because drivers are less impatient. A city near me (Federal Way, WA) recently switched all their protected lefts for protected/permissive lefts, and they saw a marked drop in collisions. People weren't "pushing the lights" like they were before.
Rural areas are certainly no place for signals (lest it's a very busy road and no money exists for grade-separation). Offset junctions are decidedly rare in the US (mostly due to rural roads being plotted in exactly straight lines), but they should be more common. It makes it way easier to cross a busy highway, and is almost certainly safer than having to look both ways and flooring it.
That's part of the point of FYA: FYA is tied to the opposing green (instead of the adjacent green), providing greater efficiency by allowing permissive turns in more situations than a standard doghouse.
Those types of left turns (negative offset, like in your image) are the ones that especially need waiting lines (dotted lines in the road that indicate where drivers should wait for oncoming traffic) (examples provided below). People typically pull straight out into the intersection when waiting to turn left. This is not good for visibility*. Optimal visibility (with negative offset left turns) is at the point when you are physically closest to oncoming traffic. Positioning your hood to be nearly on the left edge of the left lane of oncoming traffic sounds like a bad idea, but visibility is exceptionally good at this angle. If you watch any dash cam footage from places like the UK, Japan, or South Africa (both which have a lot of permissive turns), you'll see that this is where they wait.
Here are some examples of waiting lines (first from Japan, second from South Africa, third from Tucson). Note that all require waiting at an angle. The first two examples are standard road markings in those countries:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FadEp0Jr.png&hash=aea6bf8e5b7de7c1816b8538bb0036f9a3e589c5)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FY2MoGUG.png&hash=8175af12790d5a22d1d149dcedd13f67949aebc9)
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*This method of turning left originated from the idea that sitting at an angle puts you in a position to get pushed into oncoming traffic when waiting to turn left, in the event of a rear-end crash. While I have no data that shows this to be a false theory, I've also never seen any data that shows it to be true (it seems to be based on an idea of what could happen, rather than something that actually has).
I have never heard of this, but it makes so much sense. I wish lines like those were standard practice in the US. There are several intersections around here where visibility is an issue.
However, there are a few problems I can see with this. One is that a lot of our roads don't have that wide median in the third photo, so there wouldn't necessarily be room to position yourself like that.
The other problem is that normally, if you slightly overshoot the stop line at a normal intersection, no big deal. If you misjudge or overshoot this line, you will almost certainly have a head on collision.
As far as I know, the example from Tucson (the last image) is the only use of this type of line anywhere in the US. I haven't bothered to check with the head of traffic control in Tucson, but I'd really like to know where he got the idea (though I have some ideas, as you might imagine).
They wouldn't really be necessary when the turn lanes are pointed straight at each other, or when there was positive offset. Though in any case, they come in handy, especially when there's a double left yield (rare, but a waiting line to prevent the outer lane from blocking the inner lane's sightlines would be helpful). This was discussed up-thread.
The idea of "overshooting" the waiting line is possible, but turning straight into oncoming traffic is possible today even without the line. If anything, the line is a helpful reminder of, not only how far you can go without getting in the way of anyone, but also that the turn is a yield situation (unless there's an overriding signal). I suspect failure-to-give way collisions would actually drop after implementation, but I have no way of knowing for sure.
Does that mean there are 2 left turn lanes, but really there's only one because there's a cat sitting in one of them? :)
:crazy:
Just an update. All three of the intersections you posted have been updated. Intersections one and two have been changed to protected only, whereas the third now has mast-arms with new signals (still doghouses for the double left, thank God).
In the first example, they widened Popps Ferry Road and changed the signal phasing. They could have easily aligned the WB left turn so that it was offset to the left (improving visibility for EB turning traffic). But, I guess they decided protected was good enough! Oh well.
Do you remember where this was? I've was looking at a map of Duluth, when I remembered this post. But I cannot find any dual permissive lefts in Duluth. I have seen quite a few dual FYA displays elsewhere in Minnesota IRL, but they all ran protected-only. Not sure what MnDOT policy is nowadays.
Isn't MnDOT's policy nowadays to instal 4 section FYA displays for ALL left turn signal movements, even if the signal is intended to only be operated in Protected mode?
That's what I was told in the past, but that seemed like such an odd move, I've remained sceptical.
LOL, i did! Honestly, i did just for fun! :bigass:
At least one city near me has started to face this dilemma. All single-lane left turns have been converted to FYA, and while that has dramatically improved traffic, some of them don't have enough storage space. So, several major intersections have double lefts, but they're all protected-only, as is standard practice. They want to use FYAs for at least some of these double lefts, but are currently holding back until they are absolutely certain that it's the right decision.
Boise (well, I think in this case it was ITD, probably in collaboration with ACHD) recently converted a dual left turn setup to single left with FYA. It's at Broadway and Beacon. Well actually, one side of the intersection was dual left, and the other side was single left, protected only (because the opposing left turn lane blocked your view). And there are a lot of intersections in Boise and Meridian where there is room for two turn lanes, but only one of them is in use with a painted barrier where the second lane would be, with FYA. Unsure if any of those used to be protected only dual lefts.
Dual lefts are incredibly common here, and you see FYAs at almost every single left turn lane, so it will be interesting to see what happens with some of the intersections around here as traffic counts change. Dual permissive lefts could be very nice here if they ever allow them. Broadway/Beacon definitely didn't need the dual lefts, at least not now that the new Broadway Bridge opened (though this particular setup possibly pre-dates the west Parkcenter bridge which would make sense, though I'm not too familiar with Boise road history).
I'm glad to hear they didn't unnecessarily stick with the dual protected left. It's often not necessary....
California has a tendency to do something like this. They build/upgrade a new road, and they automatically build dual left turn lanes at all the major intersections and, of course, set them to protected-only. There are more than a few situations where double left turn lanes are desirable, but a lot of the ones I see don't need two lanes at all. What they need is a single-lane setup with protected/permissive phasing. Depending on the time of day, they can push more cars through an intersection than a double left. The problem, of course, is what to do at peak hours, when you might need more storage capacity, or there's too many oncoming cars for the permissive phase to be of any use. You could keep it as a single left, and switch to protected-only phasing, but that's effectively capping the throughput of the lane (permissive phasing at all times allows a variable amount of cars through during each phase, since some phases have more gaps than others, and sometimes, you'll get three or four cars turning after the red light (something that should always be practiced IMO)). You could also build a dual left with permanently protected phasing, but it will only be helpful during peak hours (though backups can still occur), and during off-peak hours, it's just annoying because you have to wait for a green arrow. The dual-permissive FYA is the result of this conundrum.
There was a document (https://goo.gl/YFi5e7) produced by VDOT several years ago (I've posted the document before -- read the ITE stories on the bottom if you haven't already), where agencies wrote in about their FYA experiences. One of the ITE (Institute of Transport Engineers) members from Wilmington, NC wrote in, suggesting something like that:
(I love the "one...out of 212" comment -- that's really it?!?)
Sounds rather complicated to me. As you might imagine, I'd rather just see FYA displays used for both lanes, with the roadway properly designed to accommodate both lanes yielding.
You are right. But I think many states are too afraid to allow dual permissive turning. In many places, it is quite common to close lanes with a red X over the lane for maintenance and similar purposes. To save people time, it is well worth while.
The stickler in me would rather just see it done properly. Obviously, at least some of these places are considering dual permissive turns. Otherwise, they wouldn't be considering the whole "close a lane off during off-hours" solution (although that's a result of being concerned with the concept). If they just designed the left turn lanes correctly, they wouldn't need to bother with anything special.
A better idea, at least compared to the lane-closing concept, might be to just only have an FYA display over one of the lanes. Kind of like banning RTOR from the left lane of a dual right turn lane.
If you just had an FYA over one lane and a standard arrow setup over the other, I think you'd get lane imbalance issues. Or you'd get compliance issues in the second lane. A blank out sign to indicate the #2 lane signal is not in use during off-peak times would help inform the driver and deal with driver expectancy.
I see the imbalance/compliance issues in Chicagoland a lot with dual rights where the inner lane is NTOR. There's also the issue of someone using the turn lane that allows turns on red turning into the correct lane and then quickly switching to the lane the NTOR lane would have turned into, possibly cutting off the driver who used the NTOR lane and waited for the light to cycle.
Using a FYA head for the permissive-prot left turn lane and a protected only head for the other left turn lane would make it difficult to provide secondary/backup/redundant signal heads for the left turns. IMHO it would be better to use lane control signals to close one of the left turn lanes or go to a modified version of Wisconsin's slotted left turn lanes (example on WI 50 near Kenosha) (https://www.google.com/maps/@42.5667493,-87.9149731,95m/data=!3m1!1e3?hl=en) with a raised median between the two left turn lanes and gate off the closed turn lane during non-peak hours.
I think you'd have the same amount of obedience issues with blank-out signs and red arrows. Neither seems like a particularly good concept. Either way, it confuses drivers who expect both lanes to work the same (instead of having one lane closed sometimes, or having only one lane allowed to yield). I think you'd probably agree that having both lanes phased the same (pro or pro/per) would be far superior.
As far as lane balance, that's an issue IRL. Virginia never allows RTOR from the left lane of a double right turn. Everyone lines up in the lane that permits RTOR.
Since jakeroot resurrected this thread from its two-month hibernation, here's a picture (which this thread inspired me to go get) of that dual-left setup in Ankeny that I took on Oct. 11. I would've posted a picture in the permissive phase, but apparently I didn't think to take one.
(https://i.imgur.com/JjPUsjE.jpg)
Nice! Freeway on ramps are the perfect place for these.
Kennewick has had a few in place since at least 2008. At the top of this page, I actually posted an image of a recent install in Kennewick. It appears as though its now the standard for double left turns.
If that were in Utah, it would almost certainly be split phased.
As I think it normally would be in Illinois and most other areas (except a few cities such as Tucson or areas around Denver). Seattle has a double permissive left turn with an option lane just like this image (except with one more through lane), which I posted an image of on the first page (the OP, actually).
No surprise really. Colorado has used dual permissive phasing all across the state for quite a while now. Here's three more examples from Colorado Springs (that I knew of previously -- these are in addition to literally hundred+ other examples in the metro Denver area). Click the photos for Street View. The double-doghouse was the standard setup (usually with a tower on the left-most mast arm), but the state has basically switched over to flashing yellow arrows at this point.
(https://i.imgur.com/yMo2psi.png) (https://goo.gl/scSZai)
(https://i.imgur.com/itumvrQ.png) (https://goo.gl/3dpTuV)
(https://i.imgur.com/9a61Rkm.png) (https://goo.gl/Cs5sp9)
Wait, which approach has the double permissive left? I see a double doghouse, but it looks like it's for when a train is approaching, and the off-ramp's center lane turns into a right turn lane (hence the double 5-section signals with right-facing arrows.
Doghouse and tower signals on the same mast arm are indeed quite rare. I've only seen it once before in Auburn, WA, and it's since been removed.
Satellite imagery from October shows only one left turn lane from Grand Ave to both north and south 35W. I'm guessing things have been modified since then? There's clearly room for another turn lane.
I thought WB 30th Street (the east leg did), but it appears I misinterpreted the signing on the mast arm - the middle sign should be an R3-5 with only a straight ahead arrow. Guess I've been corrupted lately by seeing too many option lane signs with 'only' on them and also seeing many intersections having signal heads not match intended lane usage.
I noticed that signing irregularity when you first posted the intersection (and I spent several minutes scanning the ground to confirm that it was accurate, which I was not able to). Indeed quite misleading. Typically you don't see lane use signs and specific lane control signs on the same arm. Totally understandable misinterpretation.
Great to see. It's a good place for a permissive turn, not having any oncoming traffic.
What about the traffic going EB on Broadway? It's weird to me because every other SPUI or half-SPUI I have seen has had protected left signals in all directions. Even in Tucson.
When I said oncoming traffic, I meant no oncoming *left turn. My bad. Visibility is good for turning traffic so I don't feel there is too much of an issue. Most SPUIs use protected phasing because the distance between the stop line and exit leg is so great, you'd need like a 7 second all red phase to clear traffic. But since lagging turns are used here, that's not a big worry.
Oh shit, nice find! Cannot believe I didn't know about that one. Your drive through there often?
That now brings BC's total back to four. The other three are Cambie at Marine Drive, Denman at West Georgia, and Main at the Dunsmuir Viaduct. Pacific at Burrard once had it until removal a short time ago. The Richmond example, though, is the coolest so far as it doesn't involve option lanes.
Edit: you know you're in Richmond when a Lambo just casually strolls through: https://goo.gl/vPed2y
Now that you mention it, I do feel like I'm missing something from that list. Are you thinking somewhere downtown, or outside downtown but within city limits? Never would have guessed that anyone besides the City of Vancouver would have the balls to install a double permissive left, but Richmond clearly has proved me wrong. I usually focus my search for these things in urban areas, but there could be some in suburban areas too.
Oh nice! Did not know about that one, though I rarely venture out towards UBC.
Still relatively unusual, especially for suburban cities.
God, another one I should have known about. Apparently Richmond is pretty easy-going! Cool to see those guide lines out in the intersection to keep drivers from pulling too far forward when yielding. Normally that's not an issue but it could unintentionally block a left turner if a driver places their vehicle in the wrong place. The Denman intersection could use this (for both directions instead of just one).
I guess this is the only proper 24/7 option lane double left (with permissive phasing), as, though it permits it most of the time, the Denman/West Georgia intersection does not allow straight-ahead movements between 3 & 7pm.
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I think it's best we divide cities/states/countries into two categories: formal (2+ installs), or informal (only 1 install). Places that would qualify for the "formal" category include...
* Edmonton (AB)
* Tucson & Chandler (AZ) (latter by time-of-day only)
* Kennewick & Seattle (WA)
* Huntsville (AL)
* Vancouver (BC)
* New York City
* Colorado
* North Carolina
* Texas
* Mississippi
* Minnesota (by time-of-day?)
* South Africa
* Singapore
* Japan
* Denmark
* It should be mentioned that in Washington, Oregon, Michigan, and British Columbia, drivers may turn left onto a one-way street even when there is two or more left turn lanes, on a red light or red arrow (ID excluded since turns on red arrows are not permitted there, eliminating double lefts). In this sense, these four areas technically sanction dual permissive left turns for all on-ramps with two or more left turn lanes, though a stop is required first.
Some places with what I consider to be "informal" usage (only one install) include:
* Cupertino (http://bit.ly/2AegGww) (only briefly)
* Idaho (fairly new install in Coeur d'Alene)
* Reno
* Chicago
* Springfield (OR)
* Eau Claire (WI)
* Albuquerque
* Virginia
* Maryland
* Red Deer (AB)
* Regina (SK)
and probably a few more places that I've neglected to remember at this time. Some places like St Louis and other parts of Illinois previously had dual permissive left turns, but they've been removed. Chicago is now alone in the "informal" category, and Missouri no longer has any that I know of. Las Vegas had one, but it was removed, keeping Nevada off the formal list, and placing Reno alone in the informal list.
From this 2018/August Street View image, it appears the intersection is now operating with single left turns: http://bit.ly/2T7xoVp
(https://media.giphy.com/media/12OVdvkr6sBPDG/giphy.gif)
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So it has been removed, I must report. All the old five-section left turn towers at the intersection were also replaced with FYAs.
(https://i.imgur.com/5ysXWTG.jpg)
I feared as much. Thanks for the photos.
Is there a second flashing yellow arrow on the left side of the intersection? Just curious. I can't remember Iowa policy on auxiliary traffic lights.
Nope.
(https://i.imgur.com/wZfD0JK.jpg)
Most of the time, in Iowa, there's just the overhead signal head. Rarely I'll see a left-hand arrow setup but I haven't seen any discernible reason for when and where they get applied.
Found yet another in Richmond. Southbound Aviation at Grant McConachie Way.
http://bit.ly/2GXQFHK -- << street view shot from 2015
I think the intersection was formerly a single-lane left, but was changed to a dual left, though tire marks suggest it's always been a dual left turn (with an option lane).
Any idea if this still operates with permissive phasing? I'd check myself but have a swamped schedule down here in Seattle. No free days for a while.
This street view from August 2018 (https://goo.gl/maps/yGV8DoHSoF12) seems to suggest it's operating in split phase.
It should be noted that Canada uses flashing green arrows during the protected phase at most lights. At least the ones in BC operate at 2 flashes per second, so they are not always picked up on camera. Since something like 90% of traffic lights in Vancouver operate with permissive phasing (very high understanding of yielding on green), something tells me that drivers in the street view images would not continue turning across traffic without a green arrow. I'm guessing we just can't see it.
Cool, thanks for sharing! Interesting to note that the signals were replaced in or around 2016, so the local agency responsible for the signals must think they're working OK. Otherwise, I assume they would have removed them. Many of the signals first posted in this thread have been removed, probably for similar reasons (change of heart on the part of the responsible agency, I suspect).
Sure looks like it. The double "YIELD ON GREEN" signs seem to be the obvious giveaway, although I'd like to find some street view position that showed it in its permissive phase at some point (on mobile at the moment).
It's almost definitely not split phase. All the double left split phase signals I've seen in BC use non-flashing arrows
(Examples: https://www.google.com/maps/@49.2329204,-122.8526462,3a,44y,187.49h,86.45t/data=!3m6!1e1!3m4!1sO1weXeBIgAFtF5WRu70vrA!2e0!7i13312!8i6656, https://www.google.com/maps/@49.2307959,-122.6894904,3a,19.9y,3.87h,90.51t/data=!3m6!1e1!3m4!1slFZVfZhYrRmC0fS_rG9B4w!2e0!7i13312!8i6656)
I think you found yourself a permissive double left :)
I wonder what the top part of that signal does. It's weird how it has four lights but the bottom one is a solid green. Two reds for extra emphasis maybe?
Is that the case now? In my Street View link, the second-to-top lens is still in use as a red left arrow.
Is there anybody out inthe Cupertino area who can verify that the signal actually operates in this way, i.e. that the traffic signals facing the driveways coming from the north and the south are green at the same time such that the double left turn has to be made against opposing traffic?
While that is a possibility, there is also the possibility that this signal could be split-phased without pedestrian protection. This means that the northbound traffic and southbound traffic have greens at separate phases of the cycle, yet pedestrians face walk during both parts of the NB and SB phases. So if you make a left turn, you will not need to yield to on-coming traffic, but you should still yield to the pedestrians.
Having lived in CA, I find it odd that they would ever allow a permissive double left, so it would be nice if someone has seen this signal in action.
If you look at the GSV link I posted (first one from 2008), you can see both directions green at the same time. And, that was before the installation of the pictured "YIELD ON GREEN" signs, which seems to have occurred only recently. So all things point to this being a permissive double left turn.
Nevertheless, it is indeed very possible that it now operates with split phasing, despite the signage and prior street view images. But that seems less likely given the available evidence.
You may be right. I generally do not like split-phasing, since it usually causes a lot of signal delay, but in a case where two private drive ways face each other, split-phasing works well.
Also, between 2008 and today, based only on GSV since I haven't been on this street, the city painted skip lines to mark the left turns as well as putting on the left turn yield on green signage. Perhaps in 2008, the private company simply painted the arrows they wanted without checking into the proper state traffic application. The authorities seem to have caught on, and made accommodations for it with the skip lines and the signage. Whether this also means that they adjusted the signal timing is an open question that can only be verified with someone driving by and observing it.
THe pedestrian crossing also complicates things and probably is what is preventing the installation of left turn arrows.
Did you actually see any of them operate with the FYA though? I've noticed that MnDOT/other Minnesota agencies like to install double FYA left signal heads, but these heads never actually operate with the FYA–only in protected mode.
Very familiar with this intersection! My mother makes that left turn every day on her way home from work. I don't know why I didn't post about it before.
I took a video of the intersection a month ago. Very messy intersection.
https://youtu.be/x5RbNLwuoqc
There's another North of the Capitol. Louisiana @ New Jersey (NW).
Nice find! NYC seems to have more of these than one might think. Flatbush apparently has at least two (also at Tillary).
This is also true. But even with that in mind, many locales still tend to use protected-only phasing for all double left turns, irrespective of the individual characteristics of a particular intersection (which may or may not allow its implementation given any potential hazards). What impresses me about New York (the city? Surrounding counties?) is that they don't outright ban the installation of these types of setups. Many individual cities in the country don't ban them (opposite the situation of many state DOTs, which do ban the practice), but New York is impressive in that they have quite a few, which is more than I can say about most cities.
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In terms of what? The intersection that mrsman linked to is pretty comprehensive, and the signals are very visible. Hell of a lot better than some other places.
For the linked photo at Flatbrush and Avenue U:
* No backplates on any heads.
* Given the number of lanes and amount traffic, IMHO all of the far side indications need to be 12".
* The 12" arrows next to 8" circular indications in a cluster/offset configuration doesn't look right. If these are not outright non-MUTCD compliant they are certainly pushing the limits.
* There are not any heads directly over the roadway on Avenue U - only off to the side heads. Off to the side heads can be to hard to quickly find if the driver is busy with other tasks such as navigation. I would be curious as to the number of red light violations for those legs and number of angle accidents for the intersection.
* I'm not seeing any visors on the pedestrian signals
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I don't know how many intersections with traffic lights there are in New York City, but you pretty much named every condition found at every intersection.
For that...
Backplates are never required. When the speed limit is 45 mph or above, they should have them, but not shall have them. Many intersections throughout the country don't have them. I'd even go as far to say that the majority of traffic lights country-wide don't have them.
8" lights installed prior to the recent 12" standard in the MUTCD are explicitly permitted per the MUTCD to remain in place for the rest of their useful life.
There's nothing pushing the limits of the 12" arrows next to 8" lights.
No visors are required on pedestrian signals.
So, based on this example, everything found at this intersection confirmed to MUTCD requirements at the time of installation. And as mentioned, this is pretty much a typical NYC setup, so I don't know why this intersection was specifically shown, as it's off-topic in regards to the thread.
There's four signals and four approach lanes, and many places don't use backplates. Plus, unlike many agencies, they've managed to balance the signals so that you can see at least one no matter where you are sitting. Many states put every signal directly across from the stop line. That is deficient for everyone except those at the front of the line.
Keep in mind that you proclaimed NYS as being "last" in traffic signals. I'm not here to pretend that NYC is the best in the business, but you're not identifying things that would make, at least the city, rank last.
* Backplates are nice, but it's unfair to hold it against NYC as many other places don't use them.
* 12-inch primary signals are probably wise overhead, but I don't think it's always necessary for secondary signals.
* 12-inch arrows next to 8-inch orbs were very common for a while. Still the norm in British Columbia (https://goo.gl/maps/H6Gf6QotmWZtVW8L8) (new, unactivated signals in that link). I don't see why this is a problem.
* Overhead signals are easily hidden by larger vehicles. Better to have a mix of both, kind of like the approach from Flatbush.
* As J&N indicates, pedestrian signal visors are not required. Most of the west coast does not use pedestrian signal visors (although I do like them).
I'm not going to pretend like this setup is the best in the world. There are certainly some things that I would change (adding a far-side overhead signal with a backplate, adding a right-side near-side signal, and adding a backplate to the tower signal on the far side), but NYC's traditional setups should not "rank last".
Now, what should rank last (IMO)? This is a great example (https://goo.gl/maps/sxnvcJuj2ZE4z59A7) (near Graham, WA) (this is not far from where I grew up, so I can assure you there is no bias). This is a 55-mph approach. If you are behind a tall vehicle, there's a decent chance that you cannot see the signals for a good portion of the approach. None of the BS you mentioned above (backplates, indication size, etc) matters if you can't even see a signal. This is why, IMO, NYC is actually a fair bit better than NYS, and many other states. At least the city doesn't put all their eggs in one basket (all the time at least).
FYAs are optional, not standard. Some states don't have a single FYA installed.
The worst I've personally driven through is this example (https://goo.gl/maps/frSx7vuy4d99Q4HKA) in Coahuila. A single overhead signal for each direction of a four-lane divided federal highway with very heavy commercial traffic.
Yikes, that is bad. Looks to run split-phasing as well. Also not so good.
No no, it's good. I'm glad you brought it up (despite my terrible attempt in my own post). Amtrakprod indicated that the above signal at Flatbush/Ave U was a good example of how New York State "ranks last" in signals, despite it being a NYC install. Even I know, living primarily on the opposite side of the country, that the state has totally different traffic signals. IMO, they're not as good as the city, although they have newer features (backplates, signal per lane) that give the appearance of being "better". I still prefer NYC signals, though, on account of their placement strategies.
NYC definitely operates on a "if it ain't broke don't fix it" mentality. As mentioned on other threads, they are still using 1960's tech on all their signals except to the extant it has been superseded by MUTCD. Many 8-8-8 signals. Guy wires.
Signal placement has definitely improved at many intersections. A common NYC install was to have lamppost masts at two diagonally opposite corners. A guy wire mast arm would extend diagonally into the intersection from each lamppost mast. Hanging from the mast arm would be a four-sided* 8-8-8 signal head. As noted by others above, this means that the locations are not ideal and it's often hard to see the signals as they won't be placed where the driver is looking.
See this example: 5 Av / 9 St in Brooklyn
https://www.google.com/maps/@40.6692312,-73.9862775,3a,75y,105.55h,91.21t/data=!3m7!1e1!3m5!1sQt9FaaiXXeypuuBnhYRVcg!2e0!6s%2F%2Fgeo1.ggpht.com%2Fcbk%3Fpanoid%3DQt9FaaiXXeypuuBnhYRVcg%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D305.70407%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656?hl=en
But many of these intersections in NYC are being corrected and signals are getting better placement, but it's a slow process. In Manhattan, it seems to be working better, as one of the diagonal guy-wires is replaced for more conventional supplemental signals as can be seen along Lexington Ave.
https://www.google.com/maps/@40.7421612,-73.9828895,3a,75y,193.72h,91.97t/data=!3m6!1e1!3m4!1s12URtX6UkUBz9O0Wp_1rmA!2e0!7i16384!8i8192?hl=en
I don't know the history at Flatbush & U, but I would gather that it was originally a single left turn lane with a PPLT 5 signal display. With increased traffic (headed from the Mall towards Belt Parkway), they decided to make it a double left, but did not at the same time change the signal to an exclusive RA-YA-GA signal. Maybe it's laziness, but it does allow for a double permissive turn.
Give NYC some credit - Chicago would make a 5 signal display into protected only by sign (as done on Michigan Ave).
https://www.google.com/maps/@41.8845407,-87.6244069,3a,75y,342.48h,83.16t/data=!3m6!1e1!3m4!1s63MFkaHIWSj_xZE4FQ74YA!2e0!7i13312!8i6656?hl=en
* Since there are so many one-way streets in NYC, it's rare that you'll have 4-sided signal faces as 3-sided and 2 sided are more common.
While split phasing is quite common in Mexico, I don't think this one does. I could be wrong, but I don't see any left turn arrows to make me think it does either.
I was basing it on these views:
https://goo.gl/maps/ME7bkpc2ZEvL1yFPA
https://goo.gl/maps/BMJgXEpGcc6ZgCTq5
And recently, Boston as well with this bizarre setup. The last time I was there at that intersection (24 July 2019), many drivers flat out ignored the LEFT ON GREEN ARROW ONLY sign and turned left after yielding to oncoming traffic on the green ball like it used to be...
Kneeland St and Surface Rd:
October 2018 w/ LEFT TURN YIELD ON GREEN (https://www.google.com/maps/@42.3500953,-71.059769,3a,18.9y,314.64h,98.65t/data=!3m7!1e1!3m5!1sF-EE9XAf_JhOehYRwK472g!2e0!5s20181001T000000!7i16384!8i8192?hl=en)
19 May 2019 - present w/ LEFT ON GREEN ARROW ONLY (https://ibb.co/W3QLps3)
iPhone
I was driving down Kellogg the other day and thought of you because of this sign (https://goo.gl/maps/jp36Nuo9rirbdPhx9).
If there was an issue with people "blocking the box", queuing of the left turn lanes, or accidents due to permissive left turns, I would have replaced the doghouse with FYA, and use TOD phasing to make the turns protected only during the rush hour and protected/permissive during the off-peak hours, Monday-Friday, similar to what New Hampshire does. Furthermore, I would change the phasing from leading to lagging left at this intersection as well.
BTW... your proposal of installing "straight green and yellow arrows so when the left-turn phase ends, the red ball could stay on" is prohibited in the 2009 MUTCD. See below:
That only applies to a "one signal face", not an overall setup. Protected turns with circular red indications are also a sort of engineering-faux pas at this point. I think it's allowed, but discouraged.
iPhone
I can't speak to whether the intersection in Boston mentioned needs or doesn't need protected only left turns at all times, but I can say that there is a driver expectation in most of the country (other than some of the states in the Pacific Northwest*) that a doghouse signal (or 5 phase towers) are protected/permissive and that RA-YA-GA signals are protected only. This standard should be kept, because a sign like the one in Boston seems kind of small and is very easy to overlook. If I were driving there, I probably would not notice the sign and make a left turn on green orb even without a green arrow, and I could be subject to a ticket.
Simply change the signal to RA-YA-GA if you really want left turn on arrow only. Change it to a FYA if time of day signalling is warranted.
*Jakeroot and others can confirm but in WA state (and probably a few other nearby states) left turn on red arrow is permitted onto a one-way street or a one-way freeway onramp. There is no similar rule to my knowledge in any East Coast state.
WHile the construction makes the signal placement ugly, this sign is not nearly as bad as the Chicago or Boston examples. It seems pretty clear that the left signal controls left turns and the other two signals control straight. Seeing the red ball (especially while the other signals are green) would lead me to at least suspect that the left signal controls left turns.
While the latest MUTCD recommends (or requires, not sure how to actually interpret it) that new exclusive left turn signals have red arrows instead of red balls, there are plenty of signals out there that are R-Y-GA that control a protected only left turn. They are still very common in PA and VA which use the sign "Left turn signal". This was also the standard for a while in CA, where they had a sign that read "Left turn on arrow only" (the only arrow was a green one), but in that case the left turn signal was in a 3M or louvered so as not to confuse nearby straight traffic. Very few of those remain in CA as most have been converted to red arrow.
45 states permit a left turn on red from a one-way street to a one-way street, so that's not unusual. If a turn can be made on a red arrow (in either direction) is harder to pinpoint it appears, and I don't believe an accurate list has ever been made.
I had started working on a list a couple of years ago, but I gave up quickly because it was so time-consuming to find the states' vehicle codes one at a time.
Not quite the same thing. In WA (and OR, BC and MI), you can turn left onto a one-way street from both one and two way streets (RCW 46.61.055 ~3A and 3C).
This means that left turns like this (https://goo.gl/maps/RCtcC17edLg9jCK79) are legal on red (arrow or otherwise); this is very unusual compared to virtually every other state.
Correct. In the context of protected and pemissive left turns, I am necessarily discussing left turns from a two-way street, not from a one-way street.
Outside of WA, OR, and MI (where a red left arrow would not restrict you from turning left onto a one-way):
If you are on a 2-way street, the normal expectation for a permissive/protected turn is a doghouse signal or similar variant. Basically a signal face that lacks a red arrow or other clear indication to not turn. Examples are: doghouse, 5 aspect tower [i.e. a linear doghouse], 4 aspect tower [used in some lagging turns if yellow arrow would normally be displayed at the same time as yellow orb], 4 aspect towers with bimodal arrows.
If you are on a 2-way street, the normal expectation for a turn that requires you to wait for the arrow would be a signal with a red arrow. Another variant is the R-Y-GA accompanied by a sign that this is a "left turn signal" or equivalent.
The 4-aspect FYA signal is sort of a hybrid. While normally it also indicates a permissive/protected turn, that is only true during the FYA phase. During the red arrow phase, you must wait for either the green arrow or the FYA before you can turn. And in some places with TOD phasing, it may be several hours before you can make the permissive turn.
It is terrible practice to have a doghouse or any other signal face that is normally permissive/protected used for a protective only signal. And on top of that, the sign in Boston is quite small and hard to see.
For those in WA, OR, and MI, the same holds true as well with an added proviso. Since the red arrow does not restrict the turn onto a one-way street, if the DOT in those states wanted to make the intersection a left turn on green arrow situation, the only possible way to do so is with a sign. The hope is that they pick a big enough sign. The other 47 states (including MA and IL) don't have this problem. Use a red arrow signal and don't force us to read signs that defy normal expectations.
Today while travelling from UMaine Orono to Bangor, I found this strange signal configuration downtown:
Main St and Route 222 (https://www.google.com/maps/@44.7986892,-68.7726594,3a,15y,357.18h,96.55t/data=!3m6!1e1!3m4!1sB2-zKy_N4bcmPxAicDlMgQ!2e0!7i16384!8i8192)
Setup as a lead-lag signal, the leading side only allows turns on the green arrow, and the lagging side allows permissive-protected turns. This is a close example that Amtrakprod mentioned with the straight arrows:
Without employing FYAs, the leading side of a lead-lag signal must be left turn on arrow only in order to avoid yellow trap. The problem here is that the signal is irregular and if you don't see the sign, you may end up having an accident as you expect the oncoming traffic to begin to stop as you see yellow.
And you really have to be careful how to read the sign too. When doghouses first came on the scene in Los Angeles, the vast majority of them had no sign whatsoever. I imagine the DOT believed that it was understood that if there was no sign saying otherwise, left turns were permitted on green orb. Well, at many of those intersections, people would just wait regardless, so they started putting up (in some places, not all) "Left turn yield on green." The problem with this is that now you have to read very carefully to determine if you are allowed to go on green or "left turn on green arrow only." At an intersection, there is so much to think about that the subtleties between these two signs, which mean opposite things, can easily be missed.
It is far better to have a clear rule. No left turn on red arrow. If there is no red arrow, you may turn left on green ball if you yield to opposing traffic.
The only major problem with not employing FYA in your example is that yellow trap can still occur on the lagging side if phase skip were to recall the leading left turn phase.
When our new high school opened on 11 Oct 2018 (the intersection wasn't signalised until sometime in February 2019), the signal had to be reprogrammed last-minute with anti-backup logic to prevent phase 1 (protected only) from yellow trapping phase 2 (5-section PPLT) on northbound Main St as pictured below:
(https://i.ibb.co/b6r7CV4/Screenshot-2019-09-03-at-08-16-48.png) (https://ibb.co/p13nMTH)
Once FYA's are retrofitted into this intersection (https://www.google.com/maps/@43.419976,-70.7565294,3a,75y,320.25h,89.38t/data=!3m6!1e1!3m4!1sHoOSAJv5feucDOkRBwvnKA!2e0!7i13312!8i6656) in 2021, then the normal phase skip is OK as then the yellow trap would be removed by continually flashing the yellow arrow when the oncoming green on Main St has a green light for the southbound thru traffic.
Seems to me they should use a flashing red arrow, where left on red is permitted, instead of a solid red arrow plus (maybe) a sign.
The problem, as far as I know, is that all three places, at the top-level (provincial/state), do not allow any sort of permissive left turn with more than one lane. All three have examples, but they're all city installs. Now, technically, all sanction such maneuvers by allowing these left turns on red (though I have seen signs (https://goo.gl/maps/5Sw2aymB7kkr6XP37) disallowing the turn where it would be obvious in other states that it would not be allowed), but they apparently don't want to come out and just make the maneuver obvious with flashing red arrows. I guess that would be too forward? They leave it up to people to read the relevant statutes!
I would strongly prefer this approach as well, as it would be more consistent with the rules of the other 47 states.
Here's a qn for Jake (or anyone else really familiar with WA/OR/BC rules), let's say you have the intersection of a 2-way street with a 1-way street. (Not at a T-intersection) And let's say that the left turn is controlled by a RA-YA-GA signal. This would mean that you should be able to make a permissive turn at all times, assuming you first come to a complete stop if you see a RA. (Obviously, the turn is protected with a green arrow.)
Is there any way for you to know, while you see the RA, whether you have to yield to opposing traffic or whether you have to yield to the traffic on the one-way street that is coming from your right? And what about when the traffic signal changes, is there an obvious point in time when you are aware that you have to change your yield from side street to opposing traffic (and vice versa).
I've always heard that the justification for this move is that it is not any different from a LTOR from one-way to one-way, permitted in a majority of states. (And in that case, IMO correctly, the states contend that LTOR one-way to one-way is equivalent to RTOR and generally safe.) But it seems like the need to contend with opposing traffic makes this, left from a 2-way to 1-way on red, a far riskier move.
I'm sorry that I'm missing something in your explanation. I'm not trained in TE, but obviously somewhat interested based on my posts on this forum. (I don't really understand the timing diagram.)
In my example, the normal phases are:
1. Eastbound straight and left (leading phase)
2. E & W straight, EB left prohibited by red arrow, WB left permissive on green orb.
3. Westbound straight and left (lagging phase)
4. N-S traffic on side street.
Now, from what I understand, the phase skip that you are suggesting is that at the conclusion of phase 3, phase 4 is skipped so now we are back at phase 1. If phase 3 properly closes with a yellow ball and then a red, I don't see a yellow trap problem. To allow the eastbound left, you have to prohibit the westbound straight.
If both phases 4 and 1 are skipped, then in some ways phase 3 acts like a leading left as well. You don't get a yellow arrow with a classic RYG-GA signal that was commonplace for lagging lefts, but that is still not yellow trap as those cars will now yield to opposing traffic, since the green arrow vanished.
So I guess you must mean the possibility that you are at phase 2, and phase 3 and phase 4 are skipped so you head back to phase 1. The westbound side gets yellow and red, but not the eastbound side. This is a yellow trap, since counter-intuitively phase 1 acts as a lagging phase due to the skipping of both phases 3 and 4. So as you correctly note, if both phases 3 and 4 are skipped, you must properly end phase 2 with a quick yellow and red, before allowing for phase 1 to come again.
To be honest, I have never seen that in practice. Since phase 3 allows for left turn filtering, from what i have seen it will usually be programmed for the busier left turn and will rarely get skipped.
Here is an intersection that years ago had lead-lag phasing, with protected only lead and PPLT lag. (Now both directions have protected only turns.)
Sunset at Hilgard - Copa de Oro in Los Angeles, right outside the UCLA campus.
https://www.google.com/maps/@34.0782706,-118.4393688,3a,75y,240.33h,78.77t/data=!3m7!1e1!3m5!1sWkNR_wJMf61DMNamoaADsQ!2e0!6s%2F%2Fgeo1.ggpht.com%2Fcbk%3Fpanoid%3DWkNR_wJMf61DMNamoaADsQ%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D12.513728%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192
In this example, years ago, the EB left from Sunset to Copa was leading protected only. Copa is a very minor street and got very little traffic. The WB left from Sunset to Hilgard was really major as it was a key way for traffic on Sunset (a major street in L.A.) to reach several entrances to the UCLA campus (closer to the main buildings of campus) and Westwood Village. The main bus on Sunset also made this turn, for this reason. I could never fathom the possibility that the left turn to Hilgard would ever be skipped at any cycle [phase 3], as well as the phase for Hilgard itself [phase 4] in order to service the left turn at Copa [phase 1]. I have no idea if there was ever any phase skipping precautions made here [doubt it], but it was simply unnecessary as a practical matter.
I guess the signal that in your town is different, and of course proper signaling is always important.
For these kinds of maneuvers, you have to rely on the parallel through movement to know exactly who you'll be contending with. At left turns onto on-ramps for interchanges such as Parclo B4's, there is no off-ramp to look for, so you stop on red and then proceed when safe. At left turns where there is a one-way street coming up to, and continuing through the intersection, if the through light is red, you have to watch for traffic from the right. Because there would be no oncoming left turn at 99% of these intersections, seeing all-red would only be an indication that traffic from the right has a green, not that the oncoming traffic has an advanced left or something.
As liberal as I am when it comes to this law, I will almost always wait for the parallel through traffic to get their green before creeping forward and turning on red. It's very awkward when there's a double left turn and (something like) three through lanes, and suddenly you just barge into the intersection and turn. Legal? Yes. Uncomfortable for almost everyone? Definitely.
It seems to me that the origins of the left turn law in WA/OR/BC was as it applied in a very simple intersection. No left turn arrows. Essentially 2-phase traffic signals, N-S and E-W. Obviously, in a simple situation like that, you know very well who has the ROW. But in the more modern signals with multiple phases, it can be downright complicated. Yet the law hasn't been updated.
Nexus 5X
It's acceptable to rely on the parallel through traffic in this instance, because there is no oncoming left turn that may preemptively end the parallel through phase. The next time they get a red, would be the next time that I also would need to finish my turn.
If you look at the video I made about this maneuver, you can see (at 0:46 when I first arrive at the left turn) that the parallel traffic has a red light. Because the cross-traffic is one-way, I know that it can't be red because of an oncoming left turn. I can also see traffic coming off the freeway from my right. Turning through a gap here might be unwise, so I wait for them to receive a red light. Because the double left here is lagging, the through traffic gets to go next, while the left turn onto the freeway must wait. Again, because there is no oncoming left turn, I need not be worried about the parallel through traffic receiving a red light while I'm waiting. Though to the point that it matters, I'm still legally allowed to turn on red, even if they somehow ended up with a red light. Not that that would make much sense.
In this video, however, I do make a left turn on red while the parallel traffic also has a red light. This situation is relatively uncommon, and I find it more acceptable when traffic is quiet. Skip to 0:27:
https://youtu.be/2Qa7vD0_TkY?t=46
Regarding the left turn at 0:46, even though under WA law you are allowed to make the left turn while cross traffic has green, you decide against turning during a possible short gap, due to safety concerns. So then, you do make the left turn when oncoming traffic has a green and you are able to turn during a gap. So practically speaking, this is no different than making any permissive left, yielding to opposing traffic [as opposed to cross traffic].
What really bothers me a lot about some of this is that the same signal means different things, based on the situation. It seems to ask the driver a lot to keep track of.
If I see a red left arrow crossing a two-way street, this is a protected only turn and I must wait for green arrow. This is of course the rule in the majority of other states in all circumstances.
If I see a red left arrow crossing a one-way street, I can turn anytime I want, so long as I yield appropriately. If I see a red orb nearby, that likely means that I will have to yield to cross traffic and can turn in a gap of traffic, but that is likely unsafe when it's busy. if I see a green orb nearby, this is equivalent to a normal permissive turn and I turn during a gap in opposing traffic. [IMO, this would be so much more improved with a flashing red arrow, but of course I don't dictate WA law.]
If I see a red left arrow crossing a one-way street, that happens to be two-way in the other direction. (I.e. I'm driving northbound, the cross street is one-way westbound leaving the intersection, but two-way east of the intersection.) If I see a red orb nearby, that likely means that I will have to yield to cross traffic and can turn in a gap of traffic, but that is likely unsafe when it's busy. But it could also possibly mean that opposing traffic has green and an opposing protected left to serve the two-way street.* This is really problematic. However, if I see a green orb nearby, this is equivalent to a normal permissive turn and I turn during a gap in opposing traffic, as in the case above.
If I see a red left arrow crossing a one-way street, that happens to be one-way in the other direction. (I.e. I'm driving northbound, the cross street is one-way westbound leaving the intersection to the west, and also one-way eastbound leaving the intersection to the east.) In essence, there is no cross-traffic, other than pedestrians. If I see a red orb nearby, that likely means that I will have to yield to cross traffic pedestrians and can turn. Other than the pedestrians, this is equivalent to a protected turn, since opposing traffic is stopped. But it could also possibly mean that opposing traffic has green and an opposing protected left to serve the two-way street. But it could also possibly mean that opposing traffic has green and an opposing protected left to serve the opposite direction one-way street.* This is also problematic. However, if I see a green orb nearby, this is equivalent to a normal permissive turn and I turn during a gap in opposing traffic, as in the case above.
* The two opposing left turns may not necessarily have green arrows at the same time. If they do, then this problem is largely eliminated, but at the expense of wasted green time.
These are two of the big reasons I don't like this Pacific Red Arrow law. (PRA for short, I'll call it from now on.) Consistency with traffic laws is key, and I'd call the PRA very inconsistent with both other states and with itself, for varying depending on the situation.
The Pac NW Red arrow law also applies to red orbs. Left turn from 2-way to 1-way, is basically permitted at all times.
I believe that the basic driving laws should be uniform across all 50 states. There is a lot of confusion out there, and because we live in such a free country it is very easy for people to drive from state to state without restriction.
There is no reason why if a local DOT feels that a certain intersection should be stop and then make a turn, that a red arrow couldn't be replaced with a flashing red arrow. Any intersection that should be an exception can be signed as such, but that should be rare because the expectation is that a red arrow is stop until green arrow, a flashing red arrow is stop and then proceed when safe, and no arrow would allow a permissive turn (and no need to wait for a green arrow).
I will say that making a left turn from a 2-way to a 1-way at a T intersection (where the 1-way ends at the 2-way) would seem to be a safe turn on a red orb, even though it is prohibited in most states. It's basically a protected left, except for possible pedestrian interaction. It can be permitted by sign. Here's an example from a relatively remote part of NYC (which generally doesn't even allow RTOR) to allow LTOR from 2-way to 1-way at a T-intersection.
https://www.google.com/maps/@40.6096868,-73.8190742,3a,75y,193.71h,88.53t/data=!3m6!1e1!3m4!1sKnloxMvHK6TsGqbAqOvusQ!2e0!7i16384!8i8192
So I have no problem allowing the turn in that circumstance, just add a sign.
Looking around that intersection, I'm confused. I see the one way sign for the side street indicating it's one way away from this intersection. But why are there vehicular signals facing the side street and a stop bar on the side street? Was the side street formerly two way?
It's also possible that those were formerly used as pedestrian signals before there were dedicated pedestrian signal heads installed there.
Edit to add: If you go back to the 2013 GSV imagery (https://www.google.com/maps/@40.6096222,-73.8189278,3a,75y,145.3h,84.77t/data=!3m6!1e1!3m4!1sIKLnXzv3NghKoWMQVByGGg!2e0!7i13312!8i6656), there isn't a stop line painted there. I think that might be a relatively recent addition, added in error.
Plausible explanation...until noticing that there are not vehicular signals facing the other direction on the crosswalk...
:confused:
I believe it was two-way at one point, even though it's very narrow. Making the street one-way allows for parking.
I would argue that the "PRA" is actually quite consistent, at least within the states that have it as law: you may turn on any red light, unless it's a left turn onto a two-way street. Any other unsafe turn can be marked with NTOR signs.
The law could be changed in states like ours to represent the FHWA preference, but that would end up banning many turns on red, thanks to WSDOT and ODOT's preference for using all-arrow signals over turn-only lanes, in lieu of lane-use signs.
I would agree. However, if you're in charge of the roads department in a city, and you're looking to work towards your Vision Zero goal, you'll take any improvement you can get, no matter how small. Washington DC and Seattle are two agencies that are quickly banning many turns on red. Problem is, they don't seem to recognize the ripple effects from banning these turns: intersection blocking, drivers continuing to turn even after the yellow light has disappeared, worsening traffic that results in increased driver impatience (and therefore increasingly stupid maneuvers on their part), etc. The study that I linked to above takes this into account: you could potentially improve safety for Users X with a turn-on-red ban, but there could be a likewise increase in collisions amongst Users Y, totally offsetting any improvements from the ban.
Even if there was a turn on red prohibition, there's no guarantee it will be well obeyed. I think Cook County, Illinois may be a good example of this, where a many unnecessary right on red prohibitions are degrading compliance with the more legitimate prohibitions.
Nice! I would guess that the side-street in the photo with the dual-FYA setup (Highline Ave) is relatively quiet, which is actually a great reason to install this type of signal: they can allow side-street traffic to clear far quicker than with protected-only phasing, giving more green time to the primary artery (Arrowhead Parkway in this case).
I can't recall hearing of any others in South Dakota, so I'm guessing their state DOT must not have an objection to these types of installs. Especially as this is along a state route. Of course, this installation might have been installed/maintained by Sioux Falls directly, so that's not something I could be sure of.
Had not been mentioned to my knowledge. Thanks for bringing it up. I know that NC uses this style of signal, but I hadn't seen one in a while. Not with a mast arm at least.
I've spent a huge amount of time thinking about this post. I was supposed to have been at the gym an hour ago, but here I am, still typing this post.
I am totally for FRA signals, but my primary worry continues to be that, in states like WA and OR, where protected left turns are remarkably common, many of the left turns onto one-way streets will not be swapped for FRA signals.
For example, both states disallow permissive left turns with more than one lane, but none of their double left turns onto on-ramps have NTOR signs that I've seen; basically, whether they realize it or not, they both have a ton of permissive left turns with two (or perhaps even three) lanes. Never mind the numerous left turns with only one lane that also allow turns on red, but again, would likely not be swapped for FRA signals.
I guess my only real course of action is to pursue a PE licence and take control of the signals myself!
Thinking is good for you! :hmmm:
I think you've identified some key issues about implementing some of these suggestions I had made. I never suggested changing the effect of the laws onto the PNW (or onto the very restrictive northeastern states) would be easy or cheap, it's just that it is so important that the driving laws be made uniform, with exceptions signed on an intersection by intersection basis.
Of course, the best course of action would be replacement with the 4 aspect FYA signal - which generally seem to be capable of signalling for multiple scenarios.
Ah yes, found it here: https://goo.gl/maps/pQVs2jFKQmtbMpXD8
I don't see any pedestrian signal heads or crosswalks, however, so I'm not sure what purpose the dual FYA serves. Dual right turns with permissive phasing, requiring two lanes of traffic to yield to crossing pedestrians, doesn't appear to be as taboo as left turns (thanks to one less conflict), though they're fairly rare anyways, at least outside of downtown areas. A new one was just installed in my area last year, though it uses 5-section towers (https://goo.gl/maps/4uyVMdceEnAfEi126) (despite the city's recent attempts to use right-facing FYAs for pedestrian crossings (https://goo.gl/maps/Cs8QHQBgDC4JG6sb6) at T-intersections).
What I haven't considered is the possibility of alerting local authorities to this law. I genuinely believe that engineers, locally, don't realize how liberal left turn laws actually are around here. Perhaps I could encourage WSDOT to study the possibility of using flashing red arrows at some on-ramps? Not sure how receptive they might be to that, but it beats the law changing without any modification to the traffic control infrastructure.
Found another one around Biltmore Village outside Asheville that does appear to have a pedestrian crossing. Thru signal is green when the right turns have the FYA and the pedestrian signal is active.
Punctuation and complete sentences are your friends.
Any Google Maps link?
https://goo.gl/maps/cLpjzYnQmNQUNup8A
Cheers. This one definitely has a crosswalk!
Not sure if this counts, but I may have found an unusual case in Boston of a similar case where left on red arrow is permitted with "permissive phasing":
Atlantic and Congress St (https://www.google.com/maps/@42.3537714,-71.0537625,3a,90y,133.06h,85.91t/data=!3m7!1e1!3m5!1s6lWHpxqbCkyRXLPBdjI58A!2e0!6s%2F%2Fgeo1.ggpht.com%2Fcbk%3Fpanoid%3D6lWHpxqbCkyRXLPBdjI58A%26output%3Dthumbnail%26cb_client%3Dsearch.revgeo_and_fetch.gps%26thumb%3D2%26w%3D96%26h%3D64%26yaw%3D328.80402%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192)
In this case, Atlantic is one way, the Congress approach coming from Post Office Sq is one way and the Congress approach coming from S. Boston is two way. On Congress, when the Post Office Sq thru approach is green, and the S. Boston approach has green right arrows, the left-turning traffic from Congress to Atlantic gets a red-left arrow. Because no sign is posted saying NO TURN ON RED on the Post Office approach, MA law doesn't distinguish between red arrows and balls, and also allows left turns on red from a one way to a one way, could this technically be a double permissive left? The left turn here is lagging left by the way.
BTW (edited 2021-11-01, incorrect phasing initially posted, corrected): There is a ped phase after the right turning traffic phase ends. So in hindsight, the phasing goes: right turning traffic to Atlantic, pedestrian phase crossing Atlantic, then the left turns onto Atlantic proceed before Atlantic Ave traffic is served.
I don't think a turn counts as fully protected, unless you have to wait for a green arrow. If these double left turns in Boston do not require you to wait for a green arrow, then I don't see why they wouldn't count as a double permissive left turn. Besides that, it's my thread, and I make the rules. So there.
In practice, protected and permitted turning modes are referring to the phase of the traffic signal in which vehicles can make a left turn, and how that phase interact with other active phases. It's really only describing the operation of the green or flashing yellow/red intervals that allow the turn manuever–legal turns made during the red interval after a stop doesn't make a particular turning movement permitted.
I'm not sure I would agree with that. If you are legally permitted to turn against a red signal, I don't see how that turn could be considered "protected". In the traditional sense, yes, red arrow/green arrow = protected only, and green ball/FYA = permitted turn, but a red light that permits turns on red is not only "permissive", it's more permissive than traditional left turns, because turns can be made no matter what the display is.
For example, this left turn (https://goo.gl/maps/DUcu4RGP4WYmF1XBA) can be made during the "yield on green" phase, the green left arrow phase, and the red orb phase. Obviously permissive. But what about with dedicated signals w/o a "permissive" (read: green orb/FYA) phase? At these types of intersections (https://goo.gl/maps/mdR6pmr6PUJyC9jS9), you can still turn during the red phase, as it's onto a one-way street. And, of course, you also turn during the green arrow phase. Because left turns can still be made at a driver's discretion, in a sense, it's still a permissive turn.
Pretty much every right turn is a permissive turn, as you don't need to wait for a green light. I think you would agree that a fully-protected right turn would be one where you must wait for a green arrow. I don't see how that's any different than left turns that can be made on red: in neither case must a driver wait for a green light.
And two more in Somerville as well:
Main and Beacham Street (new installation): Streetview (https://www.google.com/maps/@42.3850559,-71.0749895,3a,86.3y,15.1h,93.15t/data=!3m6!1e1!3m4!1s5DFPhnlpXHmDzrW3ws8-1Q!2e0!7i16384!8i8192)
(https://i.ibb.co/RC2HsT5/IMG-5763.png) (https://ibb.co/9qnY1HM)
Medford St and MA 28: Streetview (https://www.google.com/maps/@42.377114,-71.0889362,3a,40.4y,54.69h,89.42t/data=!3m6!1e1!3m4!1sDjBaw1a6i2hZIvSlsXnNJw!2e0!7i16384!8i8192)
Jake, you're mixing terms of traffic signal control with what the law allows drivers to do on certain indications.
For reference, here's MUTCD definitions from section 1A.13 (https://mutcd.fhwa.dot.gov/htm/2009r1r2/part1/part1a.htm):
A protected movement is one where the signal has assigned right of way to that movement, "protecting" it (in a sense) from conflicts with other movements in the intersection. Permitted turns are made during an adjacent circular green phase that has right of way, after yielding to other traffic/pedestrians that also have right of way. So a NB protected left turn is assigned the right of way during its signal phase, protecting it from conflicting oncoming and cross traffic (as well as conflicting pedestrian crossings)–but a SB right turn on red at the same time is not considered a permitted movement (even though it may be legal to do so) because SB traffic does not have right of way during that phase.
So I was aware that left turns on red were allowed from two-way streets in Washington and a few other states before finding this forum, but I hadn't considered the possibility that freeway ramps could count as a "one-way street". When I saw people discussing such a possibility on the forum, I remained a bit dubious since that seemed equivalent to arguing that turning left on red to a divided highway (with a large median) would be allowed if you were waiting at a light in the median, which I'm fairly sure would not count. I also had never seen anyone perform this movement, which made me question the idea further.
However, after paying specific attention at on-ramps, I did manage to see someone do it at the exit nearest my house, so I decided to see if I could research a definitive answer to this. I came up with this article (https://www.kitsapsun.com/story/news/2019/07/26/road-warrior-no-free-left-onto-ramp/1833502001/), where the answer to the reporter's inquiry to the Washington State Patrol was that left turns onto freeway on-ramps are not allowed. So regardless of what the intent of the law is, WSP's interpretation seems to be that such movements are not allowed.
Although, the quote in the article also states "freeway on-ramps are not considered one-way streets unless marked as such" which just makes me then wonder what such a marking would be? If it's only one-way signs, then many ramps would still qualify as lots of ramps do have them.
As the article states, that is simply one of several interpretations that I've seen over the years. For every article that comes out against the maneuver, there's another that comes out in favor.
My instinct is that the law does not reasonably differ between "streets" and other types of roadways for any ticket to stick. For the record, I have performed the maneuver around police, mostly to test my interpretation, and have not been pulled over. RCW 47.04.010 provides the definition of "highways": "Every way, lane, road, street, boulevard, and every way or place in the state of Washington open as a matter of right to public vehicular travel both inside and outside the limits of incorporated cities and towns". Because those smaller, individual terms are not defined elsewhere in the RCW, any reference to those rights-of-way should be considered "highways" (so streets = highways, boulevards = highways, etc).
According to that article, "An on-ramp is considered a designated part of the freeway". But what part of the RCW supports that assertion? I see no indication in the law that would prohibit the movement onto any one-way roads just because they're part of a "highway" or "freeway". Plus there is no reference to the term "freeway" except as defined for use on signage (WAC 468-70-020). She says that "on-ramps do not fit under the RCW 46.61.055 (section 3-c) that allows drivers to take a left after stopping at a light onto a one-way street". Yet, there is no indication in that RCW that there would be any situations where it would not apply, except when "a sign posted by competent authority prohibits such movement". I don't even see the term "on ramp" in the RCW, so how would drivers be able to assume that any one-way stretch of pavement is anything but a "one way street"?
Yeah, I'm going to keep doing it. RCW 46.61.135, which defines one-way streets, indicates that it must be marked by "official traffic control device", which include "all signs, signals, markings and devices" (RCW 46.04.611). If the markings make it clear that it's a one-way street, I don't need a sign to make it legal.
Never take an article written by some journalist who barely rolls out of bed to write their stories as fact (no, seriously - they will sit at home and write up their story on their iPhone while making a few phone calls. That's being a journalist today).
Check out this line within the article: "They said they would pull a drive over if they saw this," . How does someone pull over a drive? This hack of a reporter is what you're basing your opinion on?
The only real source of the law, believe it or not, isn't the State Police. It's the judges who make the decisions, and the lawmakers who wrote the law. This newspaper didn't even use the State Police. They used a communications CONSULTANT to the state police. Basically, they talked to someone who works with numerous different companies on any given day, and probably had very little knowledge of police policies and the intent of the law. Or, very likely, they talked to a high school friend that had some sort of job that sounded like it was important and knowledgeable.
Heck, even the journalist said that he read another source that contradicted his own source, but overruled it himself based on that there was no source listed. Couldn't even be bothered to contact his media friends to locate the source.
I would ignore this communications consultant's theory on what is a one way street. Later today, she'll probably be a communications consultant on which Halloween candy to buy that has fewer calories.
You Clearly haven't done a very close reading of the article from what you've said here.
It's a one letter typo, come on. And it's quote from a reader question, so it probably wasn't even written by the reporter. Sure the reporter could have fixed the reader's typo I guess but I still don't think that says anything about the reporter's skills!
Again you seem not to have read the article very closely. The reporter reached out to a contact at WSP, and they got back to him through a communications consultant. If you're upset about such a consultant being used, you should be mad at WSP, not the reporter.
And you are correct that the judge would be the ultimate authority to interpret the law, but it is the police who actually enforce it, my main point is that you should expect to potentially be pulled over.
Again you've missed something. He actually contacted his source again because of the contradiction, and that source "kicked it up to headquarters", who then got back to him through the communications consultant.
Also Jake, I'd advise against bringing this up to WSDOT. From my limited interactions with them I'd expect them to sooner put up "No Turn on Red" signs at every on-ramp in the state than put in any red flashing arrows. They made a big fuss over us putting in a curb on the centerline of Lake City Way (we were working for SDOT) which technically reduced the lane width 6 inches below their standard (even though it takes up the exact same space as the double yellow line already there, and it's not like that's typically driven on). They just wouldn't let it go and got almost hysterical at any rational arguments for it, it was a bit strange.
That by itself doesn't mean a whole lot to me - WSDOT could just be playing it safe. As another example of this practice: in Utah you can't turn right at a red arrow, but almost all the red right arrows I know of are accompanied by a redundant NTOR sign, probably for the benefit of those who aren't aware that the movement is illegal anyway.
But remember that it would be legal without the sign. The sign is not redundant, even if WSDOT thought [momentarily] that it was. There's also no other examples of this sign, in this kind of situation (left turn onto a freeway ramp) anywhere else in the state, that I can recall. Or probably anywhere else in the country, that I can recall anyways. If they wanted to be redundant here, why not anywhere else?
I agree with everything you're saying and agree with your interpretation of the law, but I did find a redundant "no left on red" sign, from a two way street (though at its end at a T, and not a freeway ramp, for what it's worth), in Boise, ID. https://www.google.com/maps/@43.6199959,-116.2265304,3a,75y,160.97h,86.73t/data=!3m6!1e1!3m4!1sdy6V6BkaGQ0KjaXjxgQfJQ!2e0!7i13312!8i6656
It used to be allowed there (signal on the left lane was a red ball; the turn was actually banned from the right lane, see here (https://www.google.com/maps/@43.6200485,-116.2264126,3a,37.7y,192.03h,88.51t/data=!3m7!1e1!3m5!1sH6P_QFbY0kFV4iOGoCNKrQ!2e0!5s20150701T000000!7i13312!8i6656)), then they changed it to all red arrows (which bans the movement in Idaho, I'm aware it doesn't ban it in WA and OR) and later put up the signs, which are technically redundant. Though Idaho usually puts up signs in addition when red arrows are banning otherwise allowed turns (usually right turn on red).
That is weeeeeeeeird!
Ian also posted this example (https://www.aaroads.com/forum/index.php?topic=24853.msg2447390#msg2447390) to the "Unsignalized Double Left Turns" thread.
Whether it's truly unsignalized or not, I don't know. But at any rate, it's definitely unusual. And I like it.
Edited for accuracy.
(https://media0.giphy.com/media/AaosjRHKjEcXm/giphy.gif)
This is interesting to me, as it's a dual permissive left setup at a seemingly under capacity intersection clearly built with future turning volumes in mind. The same intersection constructed in Nevada would likely have the inner turn lane blocked off with chevrons until demand necessitated its use, at the same time the permitted left would likely be removed for protected lefts.
EDIT: I don't know the volumes on Sarival Rd. But after looking at the intersection further and the movements currently existing, they probably could have gotten away with not activating this signal at all until future phases of Northern Pkwy open.
I think Washington State, and probably most other states, would have done the same. Judging by ADT numbers from Maricopa County, no section of Sarival Road averages more than ~1200 vehicles/day. Even if all of those cars turned onto Northern Pkwy, I doubt two left turn lanes is necessary.
With that said, I don't know about crash numbers. If there is no history of crashes at the intersection, it's not like two turn lanes hurts anything. Catch is, Arizona (apparently) doesn't make their crash data available for free. So I can't verify that claim. I can only assume, from imagery available from Street View, that the area is relatively quiet and likely doesn't not see many (if any) regular collisions.
Thanks. I know the Northern Parkway is a Maricopa County project, but as with any locality, the management of the signals at the ramp termini varies.
This is definitely a case where they put in all the infrastructure necessary for the future in the present. While it may make some sense to do all of the work involved for the interchange, including widening Sarival, double left turn lanes, and the signal infrastructure, while they are working on the project - I don't see how having the traffic signal operating (including the usage of electricity) is justified until traffic levels increase, probably as the area gets more developed. In other areas, the signals would be off and covered until traffic picks up, with the use of temproary stop signs as needed.
Good find. Usually in those circumstances, the crosswalk is against right-turning traffic. This is fairly unusual, but reminds me of this T-intersection (https://goo.gl/maps/u9NTfGXCjpCXoQZ99) in Vancouver, BC (double left yield to peds, no crosswalk along right edge).
Love the video. 13 year old me probably went through about half of those points at some point during the late 80's/early 90's.
While this is your thread Jake, I would prefer that examples like this not be included. There are probably many intersections out there with some form of double left that doesn't need to yield to vehicular traffic, but yields to pedestrians. Basically, T-intersections or one-way streets. But these are really different from situations where you would yield to vehicles in the way that you approach them.
If there is no opposing traffic, in what sense are you making a permissive turn? The turn is functionally equivalent to a right turn, as you have to watch for pedestrians, but during green ball phase you have no vehicles to watch out for.
In those situations, the vast majority will be turns with green ball (or perhaps FYA to highlight yielding to peds). Very few of this situation would involve a red arrow, protected only turn (such as very high pedestrian volume).
No, it's good. You make a legitimate point. I'm sure they're far more common than regular dual-permissive left turns. I don't personally know of any that work this way in WA (all my local examples are from British Columbia), which is why I was initially fine with their inclusion. But all things considered, traffic control-wise, it's certainly not as interesting as a dual permissive left across traffic.
Nevertheless, if someone wanted to share a location where a traffic light works in this fashion, I'm not sure where else they'd post about it. Another reason I was fine with it. If I ran into one in Washington, I might have considered posting it here with the caveat that it's not a true "double permissive left turn" in the sense that there is no "oncoming" vehicular traffic.
Seems North Carolina is going to test this, per https://www.ncdot.gov/news/press-releases/Pages/2020/2020-02-05-dynamic-left-turn-intersection.aspx (https://www.ncdot.gov/news/press-releases/Pages/2020/2020-02-05-dynamic-left-turn-intersection.aspx)
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Certainly interested to see how well observed the closed lane will be, particularly among drivers who might pass through the intersection 95% of the time during peak hours (and would thus be used to dual-lane operation).
That's a long one; I'm guessing lagging green arrows. Great find! Texas seems to have quite a few, but given the urban area and two-way traffic, I consider it thread-worthy.
This is the same link as before.
Got it. Hard to tell what's going on. In this link (https://goo.gl/maps/RZASymzdinCgmWiY9), it looks like it might be split-phased when the double left turn is activated. Thinking this because there are cars waiting to turn at the double left (spin camera around), but no green arrow was afforded to them.
Are we sure? Because it could be split phasing. Dallas phasing can have that appearance, unless Google Street View shows (within the same set of images) a permissive mode, followed by a protected green arrow for only one of the movements. Seeing only one direction with a green arrow (at a typical 5-section display), when the other direction also has a ton of waiting cars, is either caused by one of the directions having a lagging protected green arrow (fully protected left turn), no protected turn at all, or (rarely) the intersection operating protective/permissive most of the time, and split-phased during other times.
https://www.google.com/maps/@30.2633489,-97.7445113,3a,15y,97.94h,98.25t/data=!3m6!1e1!3m4!1sK-JcQoBYswEgWMahpYmrAQ!2e0!7i13312!8i6656
Oh, yeah. You can see it pretty clearly here too (https://goo.gl/maps/h1szkdCPJbpU5WCq9). Of course, it's operating that way during the single-left-turn mode.
I did a bit more sleuthing. Look at this image from Sep 2016 (https://goo.gl/maps/SLbqoVReu2xSWY2j9); if you look at the traffic waiting across from the Street View car, we can see a Chevy Tahoe or Suburban, as well as a 1st-gen Ford Fusion. To our right, we can see a whole load of cars waiting to proceed straight. There's also two guys walking southbound on Congress way off to the left, and a runner going eastbound along Cesar Chavez (behind, left).
Now, jump ahead one click to follow the camera car (https://goo.gl/maps/47BDmi7urPCSCBAk8) through the left turn. First, note that westbound Cesar Chavez has a red light while our left turn has a green arrow. The cars that were to our right have set off (you can see most of them well ahead at the next signal or approaching it); the two guys walking are waiting at the corner; the runner has crossed Cesar Chavez by about five car-lengths; there's other stuff too, I'm sure. But what has changed is the oncoming cars: all of them are completely different.
Note that the camera car has not made any progress relative to most of the cars that were originally to the right. This tells me that the Street View vehicle started with a solid green (yield signal), while traffic to its right proceeded off. But by the time the image was taken, the green arrow had activated for our left turn, indicating a lagging green arrow. But there is no yellow trap for one important reason: apparently, when that double left turn was installed, a fourth signal was installed on the mast (https://goo.gl/maps/nST5iSKUUKDBFRFv7). It appears that, during some hours, they run the double left turn from the 5-section signals as a protected-only turn, and the two three-section signals (one overhead, one on mast) become the through signals.
That was really hard to explain; I hope it makes some sense.
I understand this:
During peak periods, when the lane control lane is a left turn only, it operates in a split phase. During off-peak hours, it uses Dallas phasing and the lane control lane is straight only, to prevent double left turn permissive.
Actually, what I'm thinking is that the left turns operate as lead/lag during peak hours, but the double left turn is protected-only during these peak hours. This is evidenced by the extra through signal that was installed; when the two left turn signals are red, there are still two through signals for the straight-ahead movement along Cesar Chavez.
Right, right. That's what I was saying:
Bit late to reply on this, but given a strict reading of the thread's title, a left turn against a crosswalk displaying the walk signal would count. While I agree that it is quite a different in operation due to not needing to yield to opposing traffic, in Traffic Engineering terms this is still considered a permitted/permissive left turn. In fact, the "normal" right turn you mention is also considered a permitted right. (A protected right with a green arrow requires both crosswalks to be Don't Walk and is usually shown with the opposing protected left.)
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Here I am being late myself.
My original idea with creating this thread was to discuss this style of phasing, not exactly to list each example. But that's what ended up coming from that, and that's totally cool because there really should be a database of these for future study.
At any rate, I think what makes oncoming vehicles more interesting is that they are approaching at various speeds, with varying gaps, and require drivers to give a bit more thought than yielding to pedestrians (who, walking, all travel around the same speed and are certainly less dangerous to cars than the other way around). There is still something very interesting about double left turns yielding to pedestrians, as they are decidedly quite rare, but they are a bit more mundane compared to left turns where yielding to pedestrians and vehicles is required.
Now, in light of there not being a thread for listing those situations, I am fine with them being posted here. It's just that they weren't in the original spirit of the thread (which I had in my head as being "against traffic" but didn't necessarily specify, beyond the listed examples thus far all being against traffic).
What makes specific examples interesting is the extent that they are exceptions to a rule. And to the exent that they are exceptions, we try to discuss why they are present and what circumstances would lead to their being exceptions to the rule.
In most cases when you have a two-way street with a double left turn lane, the vast majority of cases will have a protected only left turn set up. Left turn permitted only with a protected left turn arrow, and left turns not permitted when opposing traffic has green. Exceptions to that occur in certain more liberal jurisdictions (like Tucson), or in situations where there are unusually good sight lines, especially if opposing lefts are also prohibited. These generally provide for a protected left, but also allow for left turns to be made during the phase of opposing traffic as well. These are interesting as they vary from the expectation. These are the main subject of this thread.
A special subset of the above can also occur without provision of any left turn protection at all and sometimes even without signals at all. You still have two left turn lanes that can turn left at times other than the protected phase. Also very unique.
With a dual left turn, where one is an option straight/left lane, the expectation is also generally a protected only turn, but for the most part, these present as split-phased signals (to avoid blocking straight traffic on green ball lights). Split-phase is a special example of protected left turn. To the extent that any of these signals are designed to allow a permitted turn while opposing traffic has right of way is also a special exception worthy of discussion (like 1st/Main in L.A. in the 1980's as Jake posted recently).
A dual left turn from a one way street to a one way street does not face opposing traffic other than pedestrians. Yes, you have to yield to pedestrians so in a technical sense it is a permitted turn. But the vast majority of these intersections permit the turn at all times. Occasionally, there may be signage (or state law) prohibiting turn on red [or prohibiting turn on red from the rightmost left turn lane]. But it is extremely rare to find a left from one way to one way that doesn't allow the turn during green ball phase. In fact, most of these do not even provide any protected left turn at all. A left turn on arrow only setup is rare and generally only present in very heavy pedestrian crossings or in the presence of protected bike lanes.
Here is an example of a left turn lane and left turn option lane from one way to one way controlled only by regular signal in Downtown Sacramento. Left turns are even permitted from both lanes on red signal. Signage reminds drivers that are turning to yield to pedestrians. Even in a downtown with a significant (but not extreme) level of pedestrian activity, no protected left is provided. Examples like this abound in Sacramento and many other cities. A protected left turn in this situation is quite rare. Those are more noteworthy than the protected/permitted left in such a case.
https://www.google.com/maps/@38.5822031,-121.5004067,3a,75y,100.9h,79.31t/data=!3m6!1e1!3m4!1sOeDqLTJ1MZbCgX-xsfn4Yg!2e0!7i13312!8i6656
Here's a similar example in Baltimore. No turn on red, and perhaps a leading pedestrain interval, but left turns are permitted without a protected left:
https://www.google.com/maps/@39.2874062,-76.6232488,3a,75y,254.33h,80.99t/data=!3m6!1e1!3m4!1sYB0-4vXZRCqp9CADR9Lozg!2e0!7i13312!8i6656
Similarly with T-interesections. If one street ends at another at a T-intersection where the terminating street has two left turn lanes, we expect the left turn to be permitted at all times that the signal is green, even if there is a pedestrian crossing. A left turn on arrow only situation is more rare, usually only used with heavy pedestrian crossings or a bike lane setup or some other unusual hazard.
Here's an example in Los Angeles, Century Park W at Olympic:
https://www.google.com/maps/@34.0532311,-118.4163626,3a,75y,114.07h,76.99t/data=!3m7!1e1!3m5!1segXAI0GciMXMGOBcJb9X7g!2e0!6s%2F%2Fgeo2.ggpht.com%2Fcbk%3Fpanoid%3DegXAI0GciMXMGOBcJb9X7g%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D305.7235%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192
Again, I don't find any of these above examples noteworthy since they don't defy the expectation. The expectation is that in situations with dual left turn lanes that only need to yield to a pedestrian crossing (and not uncoming vehicles), left turns are allowed during the permitted phase and protected lefts aren't generally even provided.
Guess I need to look around a bit more! Thanks for that fourth one.
The one at Devon looks to be split-phased. Old imagery shows both directions with 4-section signals, which (from what I can tell) are only used in Illinois at split-phased intersections or one-way streets.
Rockford has plenty of four sections with bimodal arrows for left turns. The Chicagoland IDOT District doesn't allow them, but since Chicago doesn't follow a lot of IDOT's policies (or the national MUTCD either) anyway . . .
NB Sunset Ridge Road at Skokie Boulevard in Northbrook, IL (https://goo.gl/maps/y7wNqM5fJajUkXXT7) used to have one (left + left-thru-right)
Did Joliet Street at Cass Street in downtown Joliet get removed? (https://goo.gl/maps/LSegLmDAYmpL2kmJA) (left + left-thru)
Good to know. Did not realize that bimodal signals were used in Illinois in any capacity.
Another two, that's great! I remember Brandon mentioning the one in Joliet way back when, but there was a bunch of confusion over whether it was split-phased or permissive, with the consensus being that it was permissive. If that street view image is to be believed, there's no question (and I'm sure, with you being familiar with the area, are already well aware of that). Since the image was from September of last year, I highly doubt it has been removed. I had simply forgotten about it (both it, and that Joliet was so close to Chicago).
Nice find. Judging by that imagery, not everyone is yielding properly!
I think it was mentioned that there was a temporary variation in either Springfield or Worcester (or somewhere else), but that it was removed. That would make this the only permanent one that I know of.
Bit awkward with the RHD setup leaving City Hall. Still would count, since left turns yield to everything else, no matter how awkward.
That one even has a double 5-section tower, unlike the others from Chicago. Extra cool.
It would seem that Chicago is actually full of these things.
There are/were definitely a bunch. Quite a few of those mentioned in the "completed" column were against traffic.
Probably the busiest was westbound Independence at 12th St SW, which I captured a video of last year (note two lanes of traffic waiting to turn left at the beginning):
https://youtu.be/x5RbNLwuoqc
The intersection was definitely awkward given the sheer number of movements occurring simultaneously, plus the overlapping turns and the yellow trap for eastbound Independence traffic. Oh my!
My mother works just a couple blocks from the intersection, and I've walked through it many times before (especially given the metro stop right on that corner). For as busy as it is, I don't recall any collisions or even close calls. Everything moves fairly slow, and there's so many pedestrians that it's basically impossible to not notice them.
Oddly, none of the mentioned intersections are this one at Louisiana NW and New Jersey NW (https://goo.gl/maps/cgJKeU5RptMULypk6), a near-classic double permissive left (with an option lane). Guess this one stays.
From a layman's perspective, something I think would really help DC would be better channelization of lanes. Independence @ 12th St SW could easily be improved with offsetting the left turn lanes, and certainly some improved markings would help, but I guess it's just too expensive
Not a whole lot, beyond where they're most common.
Many of the Texas variants have surprised me with their negative-offset construction, like this one in Fort Worth (https://goo.gl/maps/mSPB7j2tyuCizxG88) that was disabled due to a high number of crashes. Colorado also has a surprising number without any consideration of oncoming visibility, but they don't (usually (https://goo.gl/maps/fHkwty9a6ofw6VWTA)) construct medians on the left (without any gap on the right, like Tucson) that make visibility worse than without any median. Unlike Texas, I've not heard of any being shut off in Colorado, so they must be better-trained at handling these (not surprising given the sheer number across Colorado ... probably the highest per-capita in the US).
Another observation might be that they are sometimes used without consideration at side-streets, where there is limited available green time to call for separate movements. Three examples of this have existed along Montlake Boulevard in Seattle: here (https://goo.gl/maps/n37trFv8uAysRPDh8) (with a severe path overlap) and here (https://goo.gl/maps/bNymyZ7U4hVsLY3c6); a third example (https://goo.gl/maps/8EHbgYmrcxc9Jd1q6) now operates with flashing yellow right arrows for oncoming traffic, as does another to the south at equally-busy Rainier Ave (https://goo.gl/maps/561wVykwT6Jsfyg98).
In a similar vein, they are more common when opposite a driveway; Pierce County, WA's only example (https://goo.gl/maps/xXacktSEinz7gNxq8) of a double-permissive left was this kind of setup (now split-phased); another example (https://goo.gl/maps/wCDGCmyt3uR2JSYu5) in Tucson like this. The one in Boston just up-thread is opposite a driveway leaving city hall as well.
Another minor observation would be Washington and Oregon's lack of interest in prohibiting double-left turns onto on-ramps during red periods. Neither DOT installs double-left turns with true permissive phasing (yield on green, or yield on FYA), but rarely (if ever) prohibit double left turns on red from two-way to one-way streets. This is not a true double-permissive left in the spirit of this thread, but it's an interesting observation. In practice, they don't work any different than Maryland's flashing red arrows (though stopping is absolutely required). Idaho and Michigan have similar laws, though the former does not allow turns against red arrows, and the latter already has several true permissive double left turns along state highways, unlike Washington and Oregon.
Looks to me like the latter also operates with permissive phasing. I believe that the green arrows should be green orbs, as green arrows are not to be used when other traffic that may conflict with that movement, has anything other than a red indication. This rule is ignored fairly often these days, with the normalisation of right-turn signals (particularly those with flashing yellow arrows), but I think the rule still remains.
Confirmed in person a week ago.
This stoplight runs split phasing with a single signal head in each direction and no arrows. Even though left turns are therefore protected, you'd never know it by looking at the signal.
AADT here was 14,330 last year, with 23% buses and trucks.
Really appreciate the update! Seems like Mexico is seriously lacking in proper signalisation outside of certain areas (Northern Mexico seems to be in worse shape).
Found more in Chicago. Both seem to be a fairly central area, so I'm definitely surprised someone hasn't mentioned either:
E Jackson Drive (WB) @ S Columbus Drive (https://goo.gl/maps/nY11a5j7tpGHMycU7) (option lane) (NEW)
E Monroe Street (EB) @ LSD (https://goo.gl/maps/y8LPBSbbDavLT6659) (two dedicated turn lanes) (NEW) (no protected phase)
Chicago has quickly become #1 among largest US cities! Of the ten largest cities, those in Texas might have some onto frontage roads, but these are so damn common I don't feel like including them on this list. Really not until you get towards Seattle or Denver, do you get cities with at least a couple of known installations (Denver having quite a few, Seattle having less than in the past). Eventually, down at #34, is Tucson, which is still reigning champ AFAIK.
Monroe/LSD is against a driveway from a Yacht Club. while still a double permissive turn, given that it is a private driveway, it is unlikely to get too much traffic.
I.e. aside from a small amount of driveway traffic, this is essentially a T-intersection.
Indeed, not a ton of oncoming traffic (certainly the reason why there is no protected phase). But there is a lot of pedestrian traffic, and there does appear to be at least a few major attractions along that driveway, so I would still include it in this thread. It seems like it would be busy enough during tourist season (whenever this is, in Chicago).
As far as double left turns across driveways, I'm not against including them. I would absolutely include them, but I think each has to be considered on its individual merits: does it seem to get a lot of traffic? Does the driveway serve several businesses? Etc, etc. If it's just a regular turn across a single driveway from a home? Boring. But a double left turn across a private drive that has several active businesses and a lot of foot traffic to boot? That's pretty damn interesting.
More to the point, would the left turn receive split phasing or regular protected phasing in most municipalities? If the answer is "yes", it's worthy of this thread IMO.
Sure, it merits inclusion because it is still yielding to opposing traffic. It just should be noted that since it is practically at the end of the road (only a few feet from Lake Michigan), the nature of traffic coming out of the driveway is not huge. Although, yes, technically more than at a private driveway.
Chicago is sort of interesting in this degree. Yes, it should be celebrated that there are quite a number of intersections with permissive double lefts. But it has other issues that I strongly disagree with. It seems to have many intersections with 5 aspect signals that are left on green arrow only, when that type of signal is almost universally used for PPLTs. Yes there is signage to that effect, but it still defies the general expectation.
Indeed. On many fronts, Illinois leads the midwest (hell, the country) in their signalization efforts, with many intersections resembling California-style placement (https://goo.gl/maps/rDQLzyRtLkQb1kaH7) but with many single-lane left turns using permissive phasing (unlike most of California), and apparently quite a few double lefts using it as well. But then yes, in Chicago, you have those ridiculous "on green arrow only" signs along several major arterials. I can only assume they were installed to satisfy the Chicago DOT's requirements for X-number of through signal heads, a difficult task for those arterials where protected phasing is desired but where overhead signals are not used. But that's a fairly poor excuse with advances in signal technology and placement strategies, and things should have been fixed a while ago.
I have wondered, given the Illinois tendency to push as far forward into the intersection as possible when turning (my method, but standard Illinois practice too), if some of the "on green arrow only" signs were removed, such as the one at Monroe/LSD, if drivers would instinctively start to turn with the green ball? Or even they'd get on autopilot and wait for the green arrow anyway. Based on what I know about "FIBs", I'm surprised they're obeyed at all.
iPhone
I might still put California first, but only because of their consistency. Illinois has some terrible inconsistencies. Springfield has more consistent (and thorough) placement strategies than Bloomington, for example (who uses only basic Illinois requirements: two signals for every movement). Apparently near-side signals are not an absolutely requirement in Illinois. It just so happens that Chicago and surrounding municipalities (including ISTHA) have really good strategies.
Correct, only first in signal placement. Near dead last in signal operation.
Found this one in Downtown San Francisco (option lane) (https://www.google.com/maps/@37.7782294,-122.4009307,3a,35.3y,115.59h,82.61t/data=!3m6!1e1!3m4!1sJwO5v6S2_xSde0klRgGg_A!2e0!7i16384!8i8192). The left lane can choose between I-80 E or Bryant St, and the middle to Bryant St or continue straight to 5th St. Many drivers I've seen during rush hour, use the middle lane to turn onto I-80 E...
I believe there's another one somewhere in SF but not sure where.
EDIT: A few more -
Van Ness and Broadway (albeit temporary? - 2 left turn lanes converted from left + option) (https://www.google.com/maps/@37.7959908,-122.4235818,3a,26.4y,155.38h,91.91t/data=!3m6!1e1!3m4!1sTZ85n9eIsaQ_vM7CFlG_mw!2e0!7i16384!8i8192)
Sloat Blvd and 19th Ave (https://www.google.com/maps/@37.7345949,-122.4755383,3a,38y,89h,87.54t/data=!3m6!1e1!3m4!1sNR9Or460omA2ZMGojtK6tw!2e0!7i16384!8i8192) (left + option)
Probably given the traffic demand, both lanes SHOULD be allowed to turn left onto the freeway.
I agree. There are three lanes on that on-ramp. No reason they couldn't allow a sharp double left turn.
Again, I agree with your points. Nevertheless, it surprises me that SF installed these to begin with. I never associated California with permissive left turns along major arterials (outside of LA proper), much less any that allow left turns from two lanes. I think most Californian municipalities, and even San Francisco themselves along any reconstructed arterials, would design the road layout in a manner appropriate for protected-only left turns if the road were designed today. Which is more than unfortunate IMO, since these seem to work adequately when properly designed.
I believe Van Ness Ave (https://www.sfmta.com/project-updates/how-get-around-without-turning-left-van-ness) is being reconstructed in that area to remove left turns in that area and to add bus lanes in the middle of the road. The only left turns that are being retained are:
SB Van Ness onto EB Broadway (the example I posted)
NB Van Ness onto WB Lombard (triple left turn lane, protected only)
I wonder what will happen with the SB Van Ness onto EB Broadway double left when the entire project is complete... especially with the new bus lanes.
Also, at least one SF intersection was converted from PPLT double left + thru to protected only recently. Harrison to I-80 E's (current (https://www.google.com/maps/@37.7862294,-122.3927,3a,18y,236.57h,93.99t/data=!3m7!1e1!3m5!1sMnz8Kah0kxmLePtwMViAxQ!2e0!6s%2F%2Fgeo0.ggpht.com%2Fcbk%3Fpanoid%3DMnz8Kah0kxmLePtwMViAxQ%26output%3Dthumbnail%26cb_client%3Dsearch.revgeo_and_fetch.gps%26thumb%3D2%26w%3D96%26h%3D64%26yaw%3D240.5388%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192)) middle lane was converted from thru-left (https://www.google.com/maps/@37.7862696,-122.3926549,3a,75y,238.26h,96t/data=!3m7!1e1!3m5!1spMda-UFLSc0TVjqzQDFuhg!2e0!5s20110401T000000!7i13312!8i6656) to a dedicated only left turn lane in 2013. Of course, they had to change the phasing from PPLT lag left to protected only. Still lagging left though... (https://youtu.be/4OWi4VVqm64?t=30)(pay attention to the arrow in the distant signal)
So there was even more? Very interesting. Did you live in the area? Curious because that KRON4 video was from soon after the signal was modified, and the story seems to about the massive tailbacks being caused by that left turn. I would be interested in knowing how that signal modification has affected traffic flow. Usually the main arguments against these are either too many crashes, or pedestrian conflicts. But there doesn't seem to be that much oncoming traffic (total non-scientific observation), and there is no pedestrian crossing. So why the change? hmm.
Typically with center bus lanes, any permissive left turns are eliminated, as traffic would have to yield to buses from behind them, oncoming buses, oncoming traffic, and pedestrians. Even I think this might be too much! South Africa, a haven for permissive right turns (they drive on the left), does not allow them across bus lanes, except where the buses do not have constant green lights (such as when they have to make turns (https://goo.gl/maps/GWenWH7WENeJADd58)).
The catch will be if the BRT lanes merge with general traffic near those left turns. If that happens, the left turns can probably stay, as the primary reason for eliminating permissive turns across bus lanes is due to buses coming from behind you. Barring that, there's no reason the double left onto Broadway would need to lose its permissive phase. At exceptionally busy turns, South Africa will merge buses with traffic, but the buses get a "pre-signal" (https://goo.gl/maps/1YNWmPVQC8mobjKt6) that allows them to merge into the through lanes prior to the beginning of the turn lane. I've not seen this used elsewhere, but seems like an option for Van Ness @ Broadway and Lombard.
San Francisco is pretty well known for having many major 2-way corridors that completely disallow nearly all left turns altogether: 19th Ave, Sunset, Geary. In pre-construction days there were several intersections where lefts were prohibited from Van Ness, but it's true that more were allowed than just Lombard and Broadway. Lombard-Van Ness - Broadway is a main connecting route from the Golden Gate Bridge to Downtown SF, which is why there are multiple left turn lanes and why the lefts are still allowed even with the construction (and will probably still be allowed after the bus lanes are put in place).
I think that the bus lane would probably end at Greenwhich (one block south of Lombard). They need some way to allow for that massive left turn, and there would be no additional room for a bus lane. At Broadway, there will probably be a protected-only left (to be made from the lane that is to the right of the bus lane), but it may be limited to one lane.
I observed those double left turns when I was on holiday to Downtown San Francisco in 2013 and 2015 and passed thru Harrison and 1st Ave to get on to the Bay Bridge, as well as passing thru Van Ness Ave and Broadway on our way to the Golden Gate Bridge. The rest of the intersections were observed during Stanley Robert's former "People Behaving Badly" series when he used to work at KRON4.
Does Downtown SF use flashing yellow arrow signals for permissive turns at all?
Not to be confused with the flashing yellow balls that SF uses at some intersections:
Height and Octavia (https://www.google.com/maps/@37.7729067,-122.4240451,3a,21.3y,78.07h,89.82t/data=!3m7!1e1!3m5!1seKV6OJhQTef6_st96jXMIw!2e0!5s20170801T000000!7i13312!8i6656) (which should really an all-arrow FYA on EB Haight)
Fremont and Harrison (https://www.google.com/maps/@37.7867673,-122.3922255,3a,75y,117.16h,84.74t/data=!3m6!1e1!3m4!1sbfp70WsqzlSxX-Dg3FCNLQ!2e0!7i13312!8i6656) (again, should really be all-arrow signals, red ball for the right turn)
I'm not aware of any, but they are allowed in CA, so there should be no problem with them.
That's a very interesting example. There is technically no oncoming traffic that would proceed directly past the yielding traffic, but traffic does still need to yield to oncoming drivers (turning right into their destined lanes), as well as pedestrians. In that sense, it kind of hits the spirit of this thread. There are flashing yellow arrows for both approaches, which is fairly unusual for this kind of downtown intersection, but the oncoming traffic also has a flashing yellow arrow. I'm very interested to see what the "failure to yield" rates are for the double left turn, since both directions have flashing yellow arrows but the dominant direction, in these situations, tends to take priority (as odd as that sounds; more based on my experience to be honest).
That said, I think situations like this, involving one-way downtown streets, are fairly common. Spokane, WA has a lot of double left and double right turns downtown. I'm sure at least one or two requires yielding to peds and vehicles.
Woah! That's cool. I know that NY has some, but almost all that I've seen do not have an oncoming left, or are turns onto one-way streets. Great find!
Another one in Garden City, same county(Nassau). A lagging double permissive turn, rare for turns onto a 2 way street.
https://maps.app.goo.gl/aW6ujm7BVdTXSD9y5
Another cool find. Although moderately less interesting, given the lack of an opposing left turn. Still, yet another good find in New York.
Looks like it might have been removed: the green arrow is no longer activating for the right-most doghouse, and the option lane arrow has disappeared from the pavement. But the option lane sign is still overhead (see all three in this link (https://goo.gl/maps/TuiqD6dEaQS388wB9)). Honestly, this is how all option lane double left turns onto on-ramps should operate. I've seen some that are split phased. To force through traffic to stop just because you have an option lane seems idiotic, especially with the excellent visibility that left turning traffic would typically have (although the shrubs in this median do hamper visibility a bit).
Typically, with option lanes, I think you'd see it where the left-most signal was an FYA, and middle signal was a doghouse with an FYA instead of regular arrows, and a regular 3-section signal on the right. This is how it's done at this intersection in MN (https://goo.gl/maps/EjD6H22azDyw18Yi7).
Well, you're forcing some traffic to stop regardless. In the typical split-phase setup, the opposing through traffic has to stop. In this kind of scenario with an option lane not employing split phasing, any left turning traffic in the option lane waiting for gap in opposing traffic will block any through traffic behind them in the option lane. If this happens to be on a coordinated signal corridor, that permissive feature of the option lane is likely to break up the platoon riding the green wave.
Split phasing would force all traffic to stop, regardless. Allowing through traffic to proceed might block the option lane, or it might not. Clearly, permissive phasing allows for greater flexibility and much easier coordination. This flexibility is especially clear when you consider the time of day. During rush hour, the option lane might favor left turning traffic. During off hours, it might favor through traffic instead. Again, there is flexibility that you don't have with split-phasing.
The only legit argument might be safety, and even that's a stretch when you consider how good the visibility would be.
I saw that as well. No idea what's going on at that intersection.
Here's the permissive phase as of Sept. 2019 (https://www.google.com/maps/@33.7229332,-84.5019798,3a,68.1y,46.63h,95.27t/data=!3m6!1e1!3m4!1svKDgAqUCoMD3FofoLxTOsA!2e0!7i16384!8i8192). It's hard to see, but there is no arrow where the doghouses are, and the oncoming signal has a green. The middle doghouse is still out in this example...
Split phasing is almost always worse for overall traffic delay. The exception is if the left turn of both directions are really heavy movements. Split-phasing takes away too much time from the other phases of the intersection.
A well coordinated permissive left turn with an option lane can work really well, and overall far less delay than split phasing. This is especially true if the left turn is lagging and the opposing left is prohibited.
While I normally consider a left turn yield on green sign(or similar) language to be somewhat superfluous, I think it is necessary here. Given that permissive double lefts are so rare in California, a lot of people may just simply make the left on green without yielding, if it weren't for the sign. Another oddity about this intersection is that there is no green arrow at all in this direction. Left turns must always yield, there is no protective phase - which again is rare for any CA double left, including the ones in SF and the ones that used to exist in L.A.
Take a look at the intersection of Beverly/Palm/Santa Monica in Beverly Hills:
https://www.google.com/maps/@34.0773825,-118.3957656,3a,75y,142.85h,99.82t/data=!3m6!1e1!3m4!1sTe7bucP3okOd3P-d7JxzgA!2e0!7i13312!8i6656
This intersection is split-phased, Beverly and Palm have greens at separate times. Normally that means that the lefts are protected at all times that there is a green ball showing. But, when a pedestrian has pushed to call to cross the street, the green ball shows without an arrow. So left turners will have to yield to peds here, but not opposing traffic. If a pedestrian did not push the button, the drivers will see a green arrow and have a protected turn.
Now the Beverly side is the double left, and I believe the left is always protected with an arrow from that perspective, but having driven frequently by this intersection for many years when I lived in L.A. (but over 20 years ago), I know that there's a lot to be watchful for. It is kind of unnerving to see a green orb and think? do I have the ROW to turn? why aren't the opposing traffic advancing? do I have to still watch for peds? (A number of years ago there were no arrows at all, so this new setup is definitely better.)
https://www.google.com/maps/@34.0771874,-118.395557,3a,75y,195.66h,92.94t/data=!3m6!1e1!3m4!1sQZki2cevvqUF8YAx51k9Cw!2e0!7i13312!8i6656
A sign like this (below) would probably make things a lot better. This intersection is also split-phased.
https://www.google.com/maps/@39.0153738,-77.0788889,3a,75y,309.57h,101.14t/data=!3m6!1e1!3m4!1seQ-yT27Tmk1cBWHas8h5gA!2e0!7i16384!8i8192
The sign says "left turns yield to pedestrians on green". So it's clear that it allows for split-phasing, but if there is no green arrow, yield to the pedestrians.
Following up on Sioux Falls.
There is another at the off-ramp from northbound I-29 at Maple & Russell streets (Exit 81). This one has been in place for as long as street view imagery has been occuring, and the double left turn looks to have been in place since the early 2000s, when the interchange was reconstructed from a diamond into a parclo.
I'm going to assume that, this being the off-ramp from a state-maintained road, that this is a state-maintained intersection. Given this intersection, and other new one at Highline and SD-42 (now on street view (https://goo.gl/maps/bFt1bxak1N6zrcuW7)), I think it's safe to assume that SDDOT has given the thumbs-up to this style of phasing. It would appear that its use is conditional, based on number of lanes and the overall setup (although this is true for regular permissive left turns as well), as other double left turns in Sioux Falls use protected-only phasing (at least for those that I've located).
As a side-note: this is definitely one of my favorite interchanges in the US. There is something very elegant about the way it was designed (the placement of the free-flow ramps especially). South Dakota also has excellent signal placement, and the northbound off-ramp has a double permissive left. Just a lot of "good" things going on here, from my perspective.
https://goo.gl/maps/essAqyJ3UehQjUQe6
(https://i.imgur.com/h0WD0uz.png)
Not sure why I keep missing your posts.
Seems that, of all the double permissive left turns without dedicated turn lanes (so maybe one dedicated left turn lane, adjacent to an optional left/straight lane), they are largely permissive-only. The exception seems to be those onto one-way streets, where a lagging green arrow is most common.
An example of the above (permissive-only) is in Seattle, from NE 44th onto Montlake Blvd:
https://goo.gl/maps/5QScXHpcBvYJTQkw7
In 98% of municipalities, this would be split-phased, but it is permissive-only here. An advanced left could be used, but there is no reason as there is little oncoming traffic. Most of the time, this intersection operates as a T-intersection (practically, anyways). At any rate, a "LEFT TURNS MUST YIELD" would be a nice sign, short of changing the operation of the intersection altogether.
I have not seen an intersection operate like those two in Los Angeles and Maryland, but it is a very logical setup for an intersection that could otherwise be very low capacity when a pedestrian push-button is selected. I would be very interested to know if, in those municipalities that setup intersections in this manner, if it's acceptable to use permissive phasing with two left turn lanes, but only when the pedestrian walk sign is on (so traffic is only yielding to pedestrians, not through traffic). If the double left turn is the heaviest movement of the split-phase, and a pedestrian wanted to cross along that edge of the intersection (conflicting with the double left turn), that would, in a typical split-phase intersection, force the double left turn to wait for the entire walk cycle, all the while waiting for oncoming traffic (perhaps no one coming at all).
In Federal Way, WA, there is an offset intersection that is ordinarily split-phased, but has flashing yellow arrows for the intersecting streets when the walk signs are activated (very similar to those in LA and Maryland, but a little different). I took a video a few years (and a few pounds :-D) ago. What I don't recall is whether both walk signs activate simultaneously, or if one of the oncoming directions still has a green light during the walk phase. I need to go back and get another video!
https://youtu.be/jEVhAABx0q4
For most split-phased intersections, especially, when the split-phased side is a relatively narrow street, in my opinion it would be better if only one of the crosswalks were provided (i.e. prohibit crossing on one side of the street, the side with the busiest left turns). In that sense, we can limit the amount of time of the split-phasing dramatically.
So if the westbound to southbound left is heavier than eastbound to northbound, make the westbound left the first left and allow pedestrians to only cross on the north side of the intersection. During this first phase, westbound to southbound will have a protected left and pedestrians can cross. During the second phase, eastbound to northbound, those drivers will have to yield to the pedestrians, but since it is the last part of the signal phase, there should be few pedestrians in the way. Left turns should yield to pedestrians (only) and not oncoming traffic, but there should be no green arrow for this and it should be clearly delineated as such.
As far as your question regarding whether CA or MD allows a double left against pedestrians but not against traffic, I am not sure that exists. Generally both jurisdictions do not allow permissive double lefts, although there are some exceptions that are noted on this thread. I don't believe there is an exception to allow a permissive left on a two way street against pedestrians, but not against vehicular traffic. Of course, if we were on a one-way street, or a T intersection, where there is no possibility of oncoming vehicular traffic, double lefts against a pedestrian crossing are common and allowed in the permissive setting.
One could surmise that the MD situation [allowing a split phase with a yield to pedestrians] could exist on a split-phase where one or both sides has a double left (or left + option lane left). But to my knowledge, nothing like "yield to pedestrians on green" has been implemented at an intersection with a double left. It is also not helpful that MD still doesn't employ the flashing yellow arrow, which could make some of these situations more tenable. It should be noted that at the Connecticut/Saul intersection that I posted earlier, the left that has to yield to pedestrians is on the side with far less traffic. The busier left of the split phase does not face a pedestrian crossing at all.
I think it is far more standard for split-phased intersections to have only one crosswalk along the edge adjacent to the heavier leg's through movement, but I appreciate it when agencies try and figure something else out.
I went back and filmed the intersection in that video above, so it shows the whole phase. Turns out that when someone activates the crosswalk, and the left-facing FYA activates, the oncoming green signal (for left and right turns) is also active; you can see this happening in the second half of the video, when I cross the crosswalk on the right. So other than right-turning traffic having a green signal, every other movement occurs simultaneously. This seems to miss the point of split-phasing, and the regulatory signage for the FYA does not indicate that yielding to oncoming traffic is required.
As noted by a commentor, the solid yellow to indicate the end of the permissive FYA phase is below the FYA (see 0:18). I suppose that's a bit odd.
https://youtu.be/qA7YCmfNhv4
The new most recent streetview from March 2020 shows the arrow is back on! https://goo.gl/maps/FX9n1X2jMCCkDn6G8 I assume this wasn't available at the time those messages were posted. Since it's back, I'm thinking the light may have just been burnt out. It also suggests that the lane is indeed still an option lane since the sign was also left up, they must have just opted not to reinstall the arrows after repaving for whatever reason.
What I find interesting about this intersection is the double left from Oak St has only 1 receiving lane on Commercial Ave! :-o Seems like an accident waiting to happen for anyone that doesn't know they have to merge within the intersection. Did anyone else notice that?
Tell you what, I wouldn't to be parallel-parked where those pickups are!
What the hell!? What traffic engineer allowed that!? If the receiving area was wider, one could argue that it's two unstriped lanes merging down to one after the intersection (which is actually a thing: https://goo.gl/maps/UkpHrMMGTGRrxzCi7), but from what I can measure on Google Maps, there's only 17 feet between those lane stripes.
Intriguing, especially given how new it is! Must be a lagging green arrow? Typically, with turns onto one-way streets in downtown areas in similar situations, the green arrow comes on at the end. Could still be a bimodal signal, that displays simultaneous yellow orb and arrow at the very end of the cycle.
Is New York not usually part of New England? Because NYS seems to have quite a few (note post above mine). There's also been at least one in Mass at one point, as well as that "unsignalized" example in Brunswick, ME you posted about on page 14.
Still, probably the part of the country with the least. Several examples have now been located in California, which is the other area of the country I would have grouped in with New England. Other than that, I'm not aware of any in Utah, Montana, or Wyoming, and I don't believe Florida has any examples anymore. I'm 98% sure every other state has at least one example somewhere. MN is a weird example, with tons of double-left FYA signals, but I don't know if they actually use the flashing phase.
(https://upload.wikimedia.org/wikipedia/commons/2/2e/New_England_USA.svg)
Check out this example (https://youtu.be/q3dditaRyB8) of a double-left followed by a merge (jump to 0:55). Insanely short. But still nothing compared to merging in the turn :-D.
Thanks. It's just funny to me think of NYS as being so culturally disassociated from "New England" that fwydriver405 would be so stunned to find an example of a double permissive left, when there are countless examples in NYS, many being far less than a day's drive from all but the northern reaches of Maine. For the purposes of this thread, I would have absolutely grouped NYS with other states in that region.
That would be called "the Northeast", I suppose.
Uh, no, definitely not. Either Northeast or Mid-Atlantic, but never New England. That's exclusive to the six small states east of us.
Also, what post? I'm not seeing any NY examples posted... "post above [yours]" turned out to be pretty vague. :-D
Yes, I got it. New England is also in the Northeast but not all Northeast states are in New England. Or maybe New York is in the Mid-Atlantic region? The fact that you, as a NYS resident, aren't even sure what region it's in with total certainty, shows that it may not be as clear-cut as some make it out to be.
Reply #443; the original quote (by RestrictOnTheHangar) has an example in Nassau County. There are others on Long Island (such as here (https://goo.gl/maps/cyGHrGQ8xHpNft4M6) and here (https://goo.gl/maps/YCVr7VZmyLW25dNF8)) and other parts of NYC. Flatbush Ave has at least two (@ Tillary & Ave U), and another at Centre & Chambers in Manhattan; I think there's at least one upstate somewhere.
You'll be mocked pretty hard if you come to the real New England and say that NYS is part of it haha. They don't like us and we don't like them, the red sox rivalry didn't help.
I'm 100% sure that New York is in the Northeast. New England and Mid-Atlantic are both subsets of the Northeast. NY fits into the latter if you have to choose, but it's a bit hard to call Buffalo "Mid-Atlantic", so Northeast is really the only safe bet for the state as a whole.
I guess you could also argue that New York is simply its own subset of the Northeast: it's almost as big as New England, after all.
Got it, thank you. I had clicked on his link, but overlooked the one in the nested quote.
Honestly, par for the course for Nassau county. Plenty of bad engineering to be found.
Maybe so, although Nassau County has quite a few examples of what I'm looking for in this thread. So it's not all bad! Although it depends on your perspective, granted.
I vote for this option. :-D
This issue is confused as well on this forum given the way that the states are grouped into different regions. Traditionally, the states were divided as such:
New England: CT, RI, MA, VT, NH, ME
Mid-Atlantic: NY, NJ, PA
Southeast: DE*, MD, VA, WV, plus other southeastern states.
* DE is sometimes grouped with Mid-Atlantic.
The reason why MD, VA, WV were grouped in the southeast was because they are states that are south of the Mason-Dixon line. But today, those states have more of a northeastern feel, especially MD.
This forum groups all of the New England and Mid-Atlantic states as Northeastern. This makes for a huge group with more posts than any other region. IMO, it would have been better to keep this split as two regions: New England and Mid-Atlantic. The number of posts in each of these regions would be more manageable.
The forum groups DE, MD, VA, and WV as the Mid-Atlantic group. These states do belong together as a group as they are distinct from the more southern states and the traditoinal Mid-Atlantic states of NY, NJ, and PA. The problem is that the name doesn't really fit the group. A better name would be "near south" or the now popular "Delmarva".
In short, NY, NJ, PA are Mid-Atlantic states even though in this forum MD, VA, and WV are grouped (incorrectly) as Mid-Atlantic states. Given the new political realities in those three states, they are disctinct from other southern states.
While this intersection is signalized with 4 aspect FYA signals, GSV shows a red arrow at the same time as green orb in one of the directions. To me, it seems like the signal is probably operating with TOD changes. During part of the day, protected only, and at other parts of the day allowing for the permissive FYA indication.
I feel that this is a reasonable compromise. In many areas that are uncomfortable with allowing a double permissive turn, they could restrict it based on time of day (or actual traffic levels based on sensor readings). At busier times, it's a regular double left with protected only operation. At off times, permissive turns are allowed.
To take it one step further, during off times, the DOT can restrict traffic so that only one of the two left turn lanes is used. A red X lane (similar to what is used on reversible roads) can restrict traffic from using the rightmost of the two dual left turn lanes during times of permissive signal operation. I don't know of any place that does that, but the possibility exists. At any event, this avoids the annoying necessity of waiting forever for a green arrow at 2 a.m.
The green arrow is actually leading (bimodal yellow+green arrow) at this intersection - was expecting it to be a lagging green arrow. Could it be because of the short distance between intersections?
I usually don't get out of Northern New England a lot... I usually don't go farther than Boston or the South Shore in MA (outside of 128), west to Lowell/Nashua, and Portland and Rochester to the north. But you are correct that NYS from my part of Maine is less that a day's drive - about 5 to 10 hours depending on where you go to in NYS.
At least in my area and in New Hampshire, we don't associate NYS as part of New England but we do consider it part of the Northeast. The regions mrsman mentioned on reply no. 443 is how we view these regions though I'm not sure about DE as I have always put it on the mid-Atlantic segment for some time now.
You're sure right on that part! :sombrero: Even some of the locals in my city think NYS is a part of New England... :banghead:
I second the time of day variable phasing comment above. Navigating around shows that the older setup had doghouses over the left turn lanes, but with red arrows instead of red ball on top (for all directions). The FYAs were probably put in to comply with the MUTCD.
That's quite interesting. Do you know what the other indications of the doghouses were? I don't think I've ever seen a 5 aspect signal with a red arrow. What would each aspect be?
If I could surmise a guess, RA, YA, GA, YA , FYA. Two YA indications, one to terminate green arrow and one to terminate FYA. But I'm glad they changed to the more common 4 aspect FYA signals.
Looks like they were just regular doghouses, but with an arrow in the top instead of a light. Here's a GSV from 2018, before the FYAs went in (https://goo.gl/maps/N8ugyX6xKTjZs9gE8).
I guess to a degree its kind of like Dallas phasing*. You focus on the signal that is in front of you. If you are in the left turn lane, your signal is the doghouse. Since the only people looking at the doghouse are turning left, a red arrow makes sense. But I think for this to work, the red arrow is only on when the adjacent signals have red orbs. (but not vice versa, you could have green arrow when adjacent signals have red orbs)
* But unlike Dallas phasing it doesn't seem to block the thru signals from view, so these should not be used for lagging lefts because of yellow trap issues.
Correct. The signals are quite like Dallas Phasing, apart from their inability to allow lagging green arrows. During the permissive time of day, they operate exactly like a regular doghouse: activated with adjacent green orb signals, with leading green arrows only. During the protected time of day, the arrows are the only signal faces utilized. There is the red arrow on the top, but this makes no difference to drivers apart from during the protected times of day, when it would be displayed when the adjacent traffic has a green orb displayed.
Honestly, the fact that this kind of display wasn't more common is surprising to me. As far as I know, before the advent of the FYA, it was the only way to allow permissive left turns based on time of day. For most jurisdictions, I suspect that TOD phasing wasn't really important for single left turns; that's fairly evident when you consider that ~99% of Colorado's red arrow doghouses are/were at double left turns, where TOD phasing may actually be important to reduce crashes. Based on this, I think we can assume that Colorado was also an early adopter of double permissive left turns, and one of the first to actually consider how time of day played into crash rates.
Still kind of regret adding it as an option :-D. Only because there are 15 people who voted for neither "yes" or "no".
I don't know if this comment was directed at me. My comment around not mentioning those in Colorado is that, for those that are privy to the current double permissive left turn situation, it's already fairly well-known that Colorado has quite a lot of examples. I would have the same reaction if someone posted an example from Tucson; they're so unbelievably common in those jurisdictions, that it's simply not worth pointing out.
Normally, I would say "well, maybe they only saw one", to be a little fairer. But in places like Colorado or Tucson, they aren't really isolated. For example, considering US-89's example from Parker: I don't know how he got to Parker without seeing any others, nor how he left Parker without noticing any additional examples (be them FYA or doghouses). They are literally all over the Denver metro area, and there are multiple other examples in Parker itself (such as here (https://goo.gl/maps/obVbWeSo9gEGxquY6), here (https://goo.gl/maps/nhPzYsecDCNDbF3D9), or here (https://goo.gl/maps/ociamG7bvHDkoVzM6) -- I found these very quickly).
One exception: if your drive through Colorado was literally all freeway, I can see why you might only see one or two. Still, if you venture a couple miles off any freeway in a relatively suburban or urban area, you should see at least a couple examples.
Here is GSV (https://goo.gl/maps/bA8i5Ayc3RuAvNZ67) of three vehicles waiting their turn.
And here is a relatively clear view (https://goo.gl/maps/9sFnMddQUdA7RgYw8) of the three lanes.
Not to crush you, but your first link is literally like 10 meters downwind from my Street View link (third paragraph) :-D
Funniest thing to me is how differently they are designed in Japan compared to other places like Tucson, where there is some fairly strict design guidelines for permissive turns across traffic. Japan basically says "go past this point and you'll hit other cars", but positive and negative offset is apparently not an issue (although this makes them more like Colorado, where there is no strict design guidelines).
I do really like Japan's propensity to use in-intersection yield lines. These make sense to me, and I don't know why they aren't used in the US. They are fairly common in other countries.
I know of at least one FYA that does use the flashing phase, since I've seen it in person. I actually posted about it here before, but there wasn't streetview at the time, and I don't have a picture, but there is now: https://goo.gl/maps/NBTPF44iuPxGXmEFA. Unfortunately it only shows it with red arrows, but I assure you, it does flash! (The presence of the "Left Turn Yield on FYA" sign supports this as well.)
I believe you! Was it late at night?
Here's a GSV still that shows it with red arrows while the through traffic is green: https://goo.gl/maps/EmyGXW6G4hUXQDMR7
My understanding was that Minnesota was switching to all FYA displays, and operating them appropriately as needed. But that virtually all remained in protected-only mode, with just some operating with permissive phasing during off-peak (night-time only?) hours.
Rogers Dr NB @ Diamond Lake Rd, Rogers, MN (https://goo.gl/maps/x5sFrwC7UqHjvTzZ9) – imagery from July 2019
(https://i.imgur.com/cuWttIV.png)
It seems that the next intersection further south has a double left with FYA allowing a permissive left turn. The FYA is blank (which likely means that it occurred while the FYA was flashing and the camera captured it during the off mode). There is a car making a turn while cross traffic is coming.
https://www.google.com/maps/@44.8560521,-93.3631234,3a,73.1y,162.26h,78.98t/data=!3m6!1e1!3m4!1sAlbLLA0aAj1G90cLQ4x2gg!2e0!7i16384!8i8192?hl=en
If you move back one step (https://goo.gl/maps/8U7MQkuG82HSKygSA), it's flashing yellow.
Close, but not really in the way that I'm looking for in this thread.
An interesting case of "we need two lanes for both movements, but there's no way to fit split phasing into this intersection". So they just option the center lane and keep it protected/permissive. Very nice, NYCDOT.
This occurs in a few places in NYC for exactly the reasons you state. Generally, these involve a lagging left and opposing left being prohibited, so that someone stuck behind a car going left in the option lane can be assured that they will have the opportunity to go at the end of the cycle. Prohibiting the opposing left avoids a yellow trap problem that would otherwise be caused with the lagging left.
As this is right near the entrance to the Manhattan bridge, and a busy area, it is very rare that someone would be able to make the permitted turn, so effectively the turns only occur during the protected phase. But theoretically, yes, turns are permitted on green orb when yielding to opposing traffic.
It's kind of crazy to me to think that it was only a single lane left turn before. I would have to assume that this isn't the primary entrance to the Manhattan Bridge.
Anyone in the area care to comment how split the center lane is in terms of whether it's primarily used by left turns or through traffic?
From my experience, it seems like most people in the middle lane go to the bridge, instead of continuing down Bowery. An exception may be during the morning hours as more traffic is likely headed toward Downtown and not to Brooklyn.
Fewer people may be headed south on Bowery, given the closure of Park Row near police headquarters since 9/11. Perhaps it was this closure that caused more traffic headed Downtown to use FDR or Broadway, while having more people using the bridge take Bowery. Bowery is still not the main flow of traffic into the bridge, far more of the traffic is headed from the western side of the area and taking Canal, especially traffic from the Holland Tunnel.
This seems like an important point, and where option-lane setups can actually be quite ideal. The flow of traffic not necessarily even throughout the day, so allowing traffic to determine the dominant movement of the center lane based on time of day allows a great deal of flexibility without the added cost (and likely conversion to protected-only phasing) of a double left + double through setup.
The only real issues right now, if I had to guess, would be (A) traffic cops making the overall setup and phasing totally redundant (unless they are there to preserve order and let the signals do the work...I don't know how NYC operates in this regard); (B) the potential for pedestrian collisions (reduced by the presence of the police in A); and (C) the potential for rear-end crashes if someone in the morning hours turns left from the middle lane, and gets hit from the rear by a car used to center lane traffic continuing south along Bowery. For B and C, I think NYC drivers are well-enough versed in avoiding these situations that neither are likely major issues.
Good application of double permissive here. Even in states that are generally concerned about allowing double permissive, which CA generally is, there is a realization that where the opposing traffic comes from a really low traffic street, especially a residential one without an outlet and only a handful of houses, there is no problem in allowing the permissive turn - as is generally the case if this were a T intersection. From this view of the intersection, you can see that on a green light, there is no traffic coming from the residential street at all and that is likely the case for a large part of the day.
https://www.google.com/maps/@37.6944605,-121.8781282,3a,75y,332.9h,82.29t/data=!3m6!1e1!3m4!1snpZHTke1Oglrxh9qE_RFzA!2e0!7i13312!8i6656
Another thing to also keep in mind for NYC (and many other cities as well) which has a big problem of illegal parking and double parking. Converting the street to 4 SB lanes: 2 left onto the bridge and 2 continuing southbound can only be done cheaply by prohibiting parking for about half a block north of the Bowery/Canal intersection. [I assume that widening the street by narrowing the sidewalk is not feasible at all.] But given the rampant parking issues, the right thru lane, being against the curb, would be constantly blocked under the 2 left and 2 SB setup. So to achieve 2 lanes south with 2 lanes left, and maintain a regular parking lane on both sides of the street, having 3 SB lanes with the middle lane serve as an optional straight/left is the only way to do it, and that's what they did.
Not yet posted that I know of.
This reminds me a lot of the one above from Pleasanton, Calif: what I assume is a very busy street meeting what I assume is a very quiet street (as it was pointed out by mrsman). There is no reason to use split-phasing here because that added level of protection would so rarely ever be necessary, and the extra phase would occasionally throw a wrench into the intersection timing. Plus I'm sure drivers would grow tired of waiting for that approach to activate. I'm sure, in many cases, drivers would just barely miss that window of activation and would be kept waiting far longer than necessary.
I do think the intersection could use "yield on green" signs like the one in California, so that drivers are at least aware of the oncoming traffic having precedence over their left turn. Especially if all-green-orb split phased intersections are as common in NJ as you say.
This seems to be a bit of a special circumstance. The two left turn lanes here do need to yield, but because the street is one-way there is no opposing thru traffic here - only right tunting traffic from Wheeler. That being said, there probably aren't too many like it, because most of the time this type of configuration (heavy one-way, especially a freeway exit, opposing a light residential street) is almost always signalled as split-phase if there are multiple lefts allowed. But given Wheeler is lightly traveled, the only thing I would add is a "left turn yield on green" as the current signalization seems adequate.
Basically, this. In my experiences and observations, there are a lot of cops on duty at any one time, and unlike what some people think, they can't be all investigating crimes. They need cops on the street available for incidents. But when everything is running ok, the cops are placed at intersections just to monitor and assist as needed. In the GSV link, you see the road is closed, a few cars in the dedicated left turn lane, and the cop, as you pan downstream, appears to either be trying to wave the leading vehicle to go straight or talking to him.
The cops will also help control traffic when needed. Take for example a common one-way to one-way left turn. Hard to make that left turn when pedestrians are non-stop crossing the road. The cop, when the light turns yellow, will take a step (literally, a step), and wave some of that left turning traffic thru the end of the yellow and beginning of the red, just before the opposing direction gets the green and their walk signal. It gets a few of the lagging left turners thru, and with the cop there, keeps things under control. If you have a hotel room above the street where you can watch some of this overhead, it's fairly interesting how they do it, without it turning into a free-for-all.
A few years back, I happened to be staying near the PANYNJ Bus Terminal when a terrorist tried to set off a bomb, and was unsuccessful. Those cops on the street were instantly able to pull out the metal crowd control barriers that NYPD have placed near each intersection, blocking pedestrians and motorists from getting close, and rerouting traffic away from the incident. Once the incident was quickly determined to be a lone attempt, unsuccessful and the threat subsided, the officers allowed pedestrians thru, and when given the all clear, moved the barriers to allow traffic thru. The speed at which all of this occurs is mind-boggling for such a large city, but shows why NYC chose to keep cops at many intersection.
Oh, yeah, this is so typical of NYC Driving. And if someone were to be bumped, they at most would get out, look at it, maybe quickly get each other's info, and take off.
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https://youtu.be/sJyzGvwkNX4
Skip to 1:11:11 (1h 11m 11s)
Green signals for the railroad immediately in front of red signals for the intersection?! Oh, that's messy...
They should have implemented an overlap between the railroad signal and the traffic signal to cut down on the mixed signals displayed here (pun intended) Or, you know, use regular railroad crossing lights & gates.
It's also weird that the trains themselves seem to be controlled by a regular traffic light. This generally only occurs on streetcars or light rail, not heavy rail corridors. Does anyone know what types of trains run on these tracks?
This is rare but I've seen it on some low traffic industrial freight spurs - here's an example I know of in western Salt Lake City. (https://goo.gl/maps/YCoKT1XbRMkPtmRm6)
This one in SLC looks like a road atop the industrial spur [tracks]. In more intense shipping settings, imbedded tracks (in this usage, rails imbedded in industrial roadways and shipping yards) are fairly common, but this pix looks like a smaller industry that has appropriately their rail spur as an outlet to gain access to a signalized intersection. Almost always, longer industrial spurs are privately maintained. It ain't cheap to maintain imbedded tracks, so I hope they knew what they were getting into when they paved over the spur.
I remember watching a video of such a crossing like that in Ohio. Mason, Ohio at US 42 and Tylersville Rd (https://www.google.com/maps/place/US-42+%26+Tylersville+Rd,+Mason,+OH+45040,+USA/@39.3518976,-84.3223125,17z/data=!4m5!3m4!1s0x884059d76bc3ddd5:0x3043dd62d088a792!8m2!3d39.3518976!4d-84.3214327).
This type of train operation (traffic signals at exempt crossings) is not so uncommon, but the railroad-only traffic signal added to the intersection is very rare. For those who didn't watch carefully, the brakeman walked over to the traffic signal and keyed up the crossing preempt for the traffic signal. Before the advent of crossing predictors (train detection circuits that predict the arrival time based on train speed), this key-up was very common at most urban grade crossings. Exempt crossings require the train crew to flag the crossing before entering the street.
Back to the main topic, this type of train operation (signal key-up) is most certainly used at the double left turn crossing example in western SLC as well.
Oh, and the EXEMPT plaque (R15‑3P or W10‑1aP) is unique to the MUTCD as it is a courtesy to hazmat trucks and school buses that are otherwise required to stop at the crossing. Since many of these crossings are private and not maintained by the railroad, it is difficult to get these EXEMPT plaques maintained properly (note that most private crossing are contracted for maintenance to the railroad, which should keep them maintained).
Hard to say. There is definitely the need to yield to the opposing right turn, but this is different from standard because the street with the double left is one-way. I think that its fine to note this one, because the usual signalization for a similar setup would be split-phasing, but this clearly has EB and WB traffic at the same time.
I agree, it's not perfect in terms of being like examples from Colorado or Tucson, but it's still an example I would include in this thread. I have posted examples identical to this from both Hawaii and Seattle (basically identical).
I continue to be surprised by how many exist in Vermont. Interesting that two would end up so close to each other.
That would be the standard approach in most areas for double left turns involving an option lane. The only difference might be the use of a 4-section signal in the middle (like this example (https://goo.gl/maps/AJb3JW9tiWURXU1g7) near me).
Before anyone else shares additional examples of split-phasing: remember that this thread is for permissive lefts, not protected lefts :D.
Speaking of Vermont... I wonder if this double left in St Albans VT is still running permissive/protected at all since 2015, since the newer GSV's show this signal to run in protected only mode. (UPDATE JUN 2022: Still in Protected only mode 24/7)
2015 GSV (permissve/protected) (https://www.google.com/maps/@44.8410292,-73.0837251,3a,28.9y,146.28h,87.99t/data=!3m7!1e1!3m5!1ss_p1yt6m1y8CWAY0RqqLgA!2e0!5s20151101T000000!7i13312!8i6656), Oct 2018 GSV (protected only?) (https://www.google.com/maps/@44.8408616,-73.0836262,3a,65.7y,143.64h,85.76t/data=!3m7!1e1!3m5!1sSLugCFgWB88T3YLoo3aNxg!2e0!5s20181001T000000!7i13312!8i6656)
I can't find it in this thread, but I recall someone mentioning that it was switched to protected-only. I swear there was a news story accompanying the change, but I cannot find anything.
NYC has a few intersections similar to the Kissena @ LIE setup. Those are in fact lagging since NYC doesnt use bimodal arrows.
The 108th st intersection is a recent conversion, I actually posted about it in the FYA thread since I live by there. It used to be like the Kissena setup.
iPhone
The setup like the Kissena @ LIE operation makes a lot of sense, at least to me. The tendency to use split-phasing at signals like this seems misguided.
I was pretty sure I had seen that intersection posted somewhere before; almost certainly it would have been your post over there.
If you can get over there late at night, see if it operates with time-of-day phasing.
Once COVID ends I'll check it out. As of now VT has some covid travel things that are annoying.
Good idea to look at night. I hope it's still permissive 🤞
The double right turn should definitely use green orbs or FYAs, yeah.
Otherwise, great example! Another classic setup from New York.
New York quickly seems to be gaining as one of the states with the most examples. Colorado is still first, followed by Arizona, then Texas, then likely Minnesota and probably New York shortly thereafter. Particularly when you include NYC, New York has more examples than I think anyone here realized at first.
CO and AZ examples are more in line with the traditional notion of the mountain west, being freer, more individualistic. Drivers can decide for themselves what is safe and allowing for the permissive turn without the need for excessive over-regulation is in line with that mindset. These double lefts are more traditional - they occur in the same circumstances as permissive single lefts, just with the addition of an additional left turn lane to capture more people. To an extent, to make this work out better, CO and AZ will feature pavement markings to guide drivers where to wait while they wait for a gap in opposing traffic.
NYC is nothing like CO and AZ. Quite the opposite, particularly in light of the fact that RTOR is generally prohibited there at every intersection, unless a sign permits it. So what can we attribute the significant number of permissive double lefts that exist there? It in fact speaks to the fact that traffic is generally so heavy that the ability to make a left during the permissive phase is largely theoretical. In NYC, this is commonly found as a double left with an option lane, in places where the opposing left is prohibited, and where the protected signal is a lagging left. Taking the intersection of 108th/LIE as an example, this is an intersection that is almost always too congested to even have the opportunity for a gap during the permissive phase. Instead, the lefts will actually take place during the protected lagging phase. This is done because the streets are often too narrow to allow for two left turn lanes and two straight through lanes, yet there is enough traffic to justify two lanes straight and two lanes left, but only three lanes to work with - so an option lane is used. If one is in the option lane, a straight driver would be blocked by a left turning driver initially - but fortunately, due to the lagging left, when the green arrow comes, both straight and left turning drivers in the option lane can complete their movements without blocking each other. And as there is no opposing driver waiting to make a left turn (in NYC the permissive double left option lane is almost always a turn from a two-way to a one-way street or expressway ramp), there should be no problem with worrying about where the drivers would wait, while they wait for a gap in opposing traffic to complete their turns.
A long way of saying that AZ and CO with wide open spaces and a free mind set have a regular double permissive turn. NYC allows it out of necessity, but due to on-the-ground circumstances, the ability to turn during the permissive phase is actually quite rare and for all intents and purposes the signal behaves like a protected turn during most hours of the day.
Your explanation of New York certainly reminds me of the double left turn I put in the OP:
(Although you see four signals, there is only three approach lanes; the center lane is an option lane).
In practice, only a couple cars ever get to turn during the permissive phase, before it falls into the lagging green arrow phase (exactly like the NY examples -- this particular example is basically identical to the north-to-westbound movement between 108th and the LIE). So while there may be some inherent increase in danger with a double permissive left turn in these very busy areas, there's very little opportunity for drivers to actually engage in whatever might be described as potentially risky behavior, such as punching through a small gap or turning blindly, etc.
I think a bigger question might be how those NYC examples, or even those outside the city (I think there's a couple?), operate later at night. As far as I know, they are not set to become split-phase at night, and traffic even in NYC does eventually peter out to relatively quiet levels. The lagging phase may remain, but without as much oncoming traffic, there is certainly less of a "never any gap" situation.
At the end of the day, you're absolutely right that it comes down to mindsets. I don't think Colorado or Arizona (primarily Tucson) make them as common as they want because they have extensive studies that show them as massively safe. Rather, they just install them because the overall mindset is more about letting drivers make the calls, and letting them take the responsibility at that point. It does make me wonder if stuff like Vision Zero, which places the onus on the city engineering department to improve safety, may result in a change of mindset in places like Colorado or Tucson. I think it already has in Tucson, where FYAs with pedestrian lock-out are now very common.
The vast majority of NYC lights are on timer only - they are not demand responsive at all. The signals will likely cycle through in the same manner as they do during rush hour, although there could be some timing adjustments as well. Its definitely true that even if there were nobody wanting to make the left, the lagging left arrows would still light up.
So in lighter traffic, permissive lefts would be possible at these intersections. And using both lanes is also possible at these intersections. But given the heavy traffic, large number of pedestrians, and aggressive driving culture, what's possible doesn't equal what is actual. So you may be able to use both lanes to make a permissive left in off-hours, but it's not the norm.
Another great Long Island find. What is it with this place?!
Odd that the oncoming single-lane left turn was changed from permissive-only (https://goo.gl/maps/Ft3QFR68wDnWPiWG6) to protected-only (https://goo.gl/maps/ju3H9ncKqonZjMhRA).
Maybe the change was due to the curve. Also its odd that the double permissive left is used in Nassau but almost nonexistent in Suffolk.
"No way, that's probably split--" "never mind (https://goo.gl/maps/jzo4AvwC7ARzH3kp6)".
All of these examples must be the legacy of a few engineers. Or perhaps influence from New York City? It's very intriguing.
That was my first thought that it was split too....But then I drove through it to find out for myself that 'twas not split.
Now, this just looks wacky to me (https://goo.gl/maps/zcmUfwnFRwuGimMJ9).
This was actually one of the earlier mentions in this thread. cl94 brought it up when I mentioned the Flatbush/Tillary intersection like 15 pages ago:
And again in Nassau County: Fortunoff Way @ Old Country Rd (https://goo.gl/maps/2DpKai7RMXg5nGct5)
(I feel like someone posted this already, but I cannot confirm)
See reply #535
These shouldn't be permissive phasing as they aren't true double lefts. With the dual left/thru lane, they should only be split phasing.
Split-phasing is usually used in these circumstances because of policy, not because it actually needs to be split-phased for safety's sake or whatever.
Yes, #535 ... From yours truly
Thank you. I edited my post.
That's neat! Very unique setup too, given how they built it out of an old oncoming lane. Must be some serious left turn traffic.
It's not the only permissive double left in Virginia, but it's one of maybe two; there is another onto a freeway somewhere in the state.
Great use case for a permissive left with two lanes. Since I'm coming traffic is a minor driveway, there's really no reason to split-phase. It would be especially stupid since it's a one-way street, and split-phasing would completely block through traffic despite not having any oncoming lefts. Not that there would be much anyway.
Nice find! Would have loved to see a third FYA signal on the far left mast, but I get the feeling such signals are not so common in Kansas.
I appreciate that people continue to keep their eye out for these.
Oh, yeah. Colorado is full of these. In fact, as far as I know, CDOT is the only agency that doesn't seem to regularly install them. Pretty much every city in Colorado has double permissive lefts, with many transitioning to FYAs over the last ten years. The only rule of thumb seems to be protected-only when the double left is extremely busy, or if there are more than two left turn lanes.
Going back in historic satellite imagery, it seems that lane has been blocked off since at least the 60s (https://www.historicaerials.com/location/37.7346328425705/-122.47479492136192/1968/18). With that double left turn, it seems visibility would have been poor enough that it was just easier to eliminate it. Seems to have been replaced by U-turn maneuver at 21st.
True. It seems that many of the permissive double lefts in CA occur in situations where the opposing left is prohibited (or at least restricted to left on arrow only). Part of the reason is that drivers making the opposing left could advance and camp in the middle of the intersection while they wait for the gap. This will certainly impact the visibility of traffic making the double left.
So I guess when the city decided that a double left was appropriate, they then prohibited the opposing left. Makes sense.
I think that's a reasonable concern.
Oh yeah, there's another nearby: https://goo.gl/maps/W2sBPjURFyENcZyJ6
What's weird about that intersection, though, is the other direction of Strang Line Road has a protected-only signal for a single left turn: https://goo.gl/maps/gXdAG3YogLu2DRhm9
Another good find, very cool!
I've definitely seen that setup before, with a double permissive left opposing a single lane protected-only left. Pretty much all have been for one of three reasons: (1) military base gate (https://goo.gl/maps/RsuKYpdSeyvG5SDw9); (2) poor visibility (maybe the reason here?); (3) not enough room to accommodate both directions waiting simultaneously (very rare -- cannot recall examples off the top of my head).
Another possibility may be signalization. Now, this is not so common or necessary any more where FYAs are used, but in some jurisdictions there may still be fear of yellow traps and perceived yellow traps.
Let's say that we are not using FYAs (or Dallas phasing or other mechanisms to avoid yellow trap). So if you signalize a lead-lag signal, the leading arrow must be a protected only turn, if the lagging arrow is permissive/protected, in order to avoid yellow trap. And when you have a situation like that, it is better to make the busier of the two lefts, the lagging left so that as many people as possible can turn left during the gaps in traffic.
Earlier, we established that for an option lane setting, it is far more desirable to signalize that as a permissive lagging left. This is because when there are three lanes, and the left lane turns left, the right lane goes straight, and the center lane is an option lane, it provides some assurance for drivers that if they are waiting in the option lane behind someone turning left -- there will be an opportunity to proceed before the end of the phase. The left turners can filter during the natural gaps, and of course the protected turn at the end will allow both straight and left folks the opportunity to proceed until the light turns red.
Now it is true that if you go back up this thread and you see the many examples of option lane arrangements with permissive phasing, they would primarily have a lagging left and they will also prohibit or restrict the opposing left. A restricted left is a leading left that only allows for a protected turn.
It seems like we only discussed this a few weeks ago. 19th and Sloat in San Francisco has a lagging, permissive, option lane arrangement for the eastbound to northbound left. Yet, there is a left turn bay for the westbound to southbound left -- a remnant of a once permitted turn before there was a double left in the opposite direction.
Let's say that SF (or Caltrans) decides that they want to reintroduce that westbound to southbound left. The best way to do it would be a leading protected-only left, so as to not impact the visibility of the eastbound to northbound turn and to not introduce a yellow trap at the intersection. And that would be a situation with a permissive double left, but a protected-only opposing single left.
Same here, never seen one in Wyoming.
Virtually zero historic Street View imagery, but it looks to have been installed around 2008 or 2009.
Down the road, I actually found another example using a double side-by-side 5-section signals (similar to those used in Colorado), complete with a "left turn yield on green" sign:
https://goo.gl/maps/yX5vbovGh2yNgQvs8
Couple other interesting things about this intersection:
* there is no pedestrian signal for the southeast-to-southwest crossing
* flashing yellow arrows are used for Dewer Dr but not the double left turn (as they shouldn't since it's a shared left/straight/right lane)
* the opposing approach uses only post-mounted signals
Looking again, it does seem that GSV may have passed through mid-construction. There are no sidewalks anywhere, but there was in older imagery. This tells me that they were in the process of installing the new pedestrian equipment? Maybe. I would hope so, as there was a pedestrian signal on that corner before.
GSV here (https://goo.gl/maps/qvyiByyN8hzi5uF87), in case anyone else, like me, didn't know at first what state you were even talking about.
Car didn't run red light. Go back a little and you'll see the light was still yellow when he was past the stop line turning.
Watch Welcome Back Kotter on DVD or Hulu and the final season openers show the car filming the drive under the elevated subway drives through a red light.
To support Jeff and Nicole.
https://goo.gl/maps/UdxnneyaY1HPEnJ39
When developing a fictional idea for Chicago in the Fictional thread, I stumbled across this intersection in Chicago:
https://www.google.com/maps/@41.9854845,-87.6601596,3a,75y,173.78h,83.64t/data=!3m6!1e1!3m4!1sKNDU36-2SYD7WIt981cncw!2e0!7i16384!8i8192
Broadway at Hollywood, with an option lane. A few blocks from the north end of LSD. A few blocks from Sheridan/Bryn Mawr which is mentioned upthread.
[I don't think this was mentioned upthread, I searched.]
I know there's lots of CO examples, but here is another one I drove through yesterday (https://www.google.com/maps/@39.5948762,-104.7873499,3a,75y,46.34h,90.26t/data=!3m6!1e1!3m4!1sH0jEpgbxLtS505q_JlYIEg!2e0!7i16384!8i8192) just south of my house. Had never really paid attention before.
Yeah, rare example! Richmond actually has a couple more examples, one on the other side of the No. 2 Road Bridge (here (https://goo.gl/maps/6wmJGfeFujJ6pacu8)), and another leaving the cell phone lot at YVR (here (https://goo.gl/maps/gfb6nGUNkBGieLaL8)).
I actually have a video of the example you linked to. They've since replaced all of the signals with 12-inch lenses (seen here (https://goo.gl/maps/VrrPQy7DhFpNcVLo8)), so they are evidently committed to the permissive phasing:
https://youtu.be/65MP7m4qTtA
I can see in real life that only the green section is an arrow. So would it flash yellow for the EBLT, solid green for through, and red for WBLT? Interesting.
Doubly interesting (no pun intending) because there is no supplemental left turn signal on the far left corner. That's typically standard in New Mexico, especially at double left turns. Well, at least with it being permissive, the overhead and supplemental right corner signal technically mean the signal meets the two-signal minimum rule.
I will add that New Mexico has a surprisingly high number of permissive double left turns. I think they're in the top five, perhaps behind only Colorado and Texas.
Agreed with that assessment, I suspect it wasn't worth split-phasing. Although it's got me wondering how common such a setup is.
There is one other identical approach in Eden Prairie as well: https://goo.gl/maps/AB3ktBEx8e15CDka7
I guess a good term for this kind of setup, given that there is apparently more than a couple of them in the state, is the "Minnesota-style option lane double permissive turn"...maybe someone can think of something catchier.
There is definitely more than a couple!
I found a third one in Elk River.
Could you indicate where? I glanced around but didn't see any specific locations with the option-lane double permissive left turn setup like the two just mentioned.
So, this is what happens when I don't proofread my own posts because I post too late at night.
https://www.google.com/maps/@45.3077572,-93.5774317,3a,75y,184.13h,90t/data=!3m7!1e1!3m5!1skLHdqbvOPrTIFWd3Mw33dg!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DkLHdqbvOPrTIFWd3Mw33dg%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D182.91048%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192
Sorry for the runaround.
All good! Thanks for sharing that. No wonder I didn't spot it while browsing overhead, it was just installed and not shown on globe satellite view. Although it is shown on non-globe satellite view...note to self, turn off globe satellite mode when looking for most recent imagery!
In terms of the setup, it seems like there may be some path overlap. I'm curious when it's set to operate, I'm able to see GSV imagery showing it operating, but it's operating more as a split-phase intersection.
I wonder why Wisconsin insists on using so many heads for everything. I appreciate good supplementary heads, but this is getting ridiculous.
Also, although in a completely different place, I found a Mississippi setup that uses double doghouses... in the middle of the day, with both left turn directions going at the same time, at an intersection with US 90, completely unlike the example you just sent. Duaity of man I guess.
https://www.google.com/maps/@30.4161172,-88.8277286,3a,24.9y,173.78h,94.98t/data=!3m6!1e1!3m4!1sN1IQDLKTGHznubnJzg7iwA!2e0!7i16384!8i8192
Actually, the new standard for Wisconsin is all overhead with one nearside signal for each maneuver, which is not really that impressive. Even most Illinois districts require both one nearside signal and one far left corner signal. Eau Claire, on the other hand, goes a bit above and beyond, looking more like California or Nevada with their new installations compared to the rest of Wisconsin.
Very nice! That's a great example of a positive-offset left turn for the opposing single lane left turn. This is preferred as it massively improves visibility for left turning traffic.
I don't know what New Mexico's rules are for double left turns, but it seems they have no rule specifically prohibiting permissive lefts with more than one lane.
I am said local! These dual FYAs along with the ones at Clairemont/Stein, begin their p/p phasing around 7:30-8pm during the weekday, and Clairemont/University around 7pm. On the weekend University is p/p 24hrs. The dual protected FYAs at Hastings & Brackett run recently switched to running protected only during the day, it switches to p/p around 7pm.
There are actually plans to swap the final WisDOT intersections that have 3 section LT heads in our area over to 4 section FYA heads in the next year or two, aside from the SPUI. STH 178/Seymour Cray Sr in Chippewa Falls now has a NB to WB dual left with p/p FYAs, running the same phasing as the clairemont ones do. River Prairie Dr & US53NB ramp in Altoona, STH 124 & CTH OO in Lake Hallie, and both of the STH 178 & STH 29 Ramp intersections in Chippewa Falls are set to be eventually converted to this head style. Not entirely sure if any of those will drop one of the left turn lanes to compensate. For a while Eau Claire had the highest concentration of protected only left turn signals in the entire state and now we have eliminated most of them 15 years later.
If you ever want to know more about anything Eau Claire feel free to shoot me a PM, I could go on for hours and hours, and can probably get you videos of just about anything too!
Well found.
I wish they would have modified the oncoming left turn to positive-offset alignment (against oncoming traffic instead of against through traffic), as that would have improved visibility for left-turning traffic. But maybe it works okay. I know Tucson swears by some kind of clearance zone between the through lanes and the left turn lanes.
Also interesting that they don't have white FYA signs next to the signal heads.
Technically, a sign is not required (despite so many jurisdictions using one). Since MUTCD didn't require or even recommend a sign, that probably explains why there's so many different FYA sign designs out there...
It's just that it seems like I've always seen one in Texas wherever there's an FYA.
Update on the Vermont double permissive lefts. Managed to visit all three locations on 11 June on a day trip to Burlington. Here is what I found:
US Route 2 at University Heights (https://www.google.com/maps/@44.4744303,-73.1954092,3a,35.6y,54.89h,84.69t/data=!3m6!1e1!3m4!1sqU4mNlgDIpby3ZwN85XmVg!2e0!7i16384!8i819) in Burlington in UVM is still running a double permissive left on the Univ. Heights approach. Seems to run a lagging left setup (yellow trap risk) since the first side street phases were green balls in both direction, but since side street volumes were low, the arrow never came on.
Beaumont Ave and Carrigan Drive (https://www.google.com/maps/@44.475821,-73.19265,3a,24.8y,186.4h,85.56t/data=!3m6!1e1!3m4!1sDMQ344T5QDAEkA_uedCzKQ!2e0!7i13312!8i6656), also in Burlington in UVM does NOT run a double permissive left setup, it ran split (with a green left arrow on one of the heads) when I drove thru there.
US Route 7 at Vermont Route 207 (https://www.google.com/maps/@44.8408532,-73.0836153,3a,29.3y,154.02h,87.84t/data=!3m6!1e1!3m4!1s7lcTy_AjEBNLYeDs24lLmg!2e0!7i13312!8i6656) in Saint Albans VT did NOT have the permissive phase active when I went there, even under what I assume was under free operations (although it seemed like it was running pretimed and not free... broken detector?)
Not to completely steal your thunder, but I did post this same intersection a couple years ago:
https://www.aaroads.com/forum/index.php?topic=17051.msg2496801#msg2496801
Very cool! Perhaps the only one upstate for that matter...there are a bunch in NYC-proper, but I'm not aware of others in the state.
Interesting. I'll have to check that out sometime. The new(-ish) installs on NY 15A at I-390 less than a mile away are protected-only. Wouldn't be surprised if it's because there's only a single oncoming lane.
This intersection also qualifies for my lanes that disappear mid-intersection (https://www.aaroads.com/forum/index.php?topic=30385.0) thread, so I'll post this there too. :)
There are a few in NYC itself unless I'm missing a bunch. I think the one at Flatbush/Tillary may be gone now that the intersection was reconfigured to have a shared through/turn lane. Queens Boulevard is still there. The one in Rochester, yeah, that's the only one Upstate. I wonder if that operates as FYA 24/7 or only part-time.
It's great that they are trying something new. The lack of permissive double lefts around NY (other than NYC) indicates that the DOTs are nervous about the concept, so to try out something that works well in other places and is legal and helpful to traffic is great. See if it works and then expand to other locations.
There are so many split-phased signals out there, because of a double left in one direction, that could probably be re-arranged to be permissive left given the realitiies of traffic flow. I know of several in my area that are similar to this, where oppsing traffic is very little so permissive lefts should be totally fine. But, alas, they are still stuck with the split-phase that delays the entire intersection.
Looks like Flatbush and Tillary is still permissive (https://goo.gl/maps/qhAr24U2Mtpnz1jq8). Based on the number of cars still in the intersection in my GSV link, hopefully there's a long all-red phase.
Edit: better link that actually shows what I was talking about.
https://www.google.com/maps/@40.6102145,-73.9221447,3a,75y,179.81h,87.94t/data=!3m6!1e1!3m4!1svwNM06bFiNkVZZlenHfFJA!2e0!7i16384!8i8192
EDIT TO UPDATE: Just looked at the Google street view today. It's protected only now. Also, Ave U was renamed to Kings Plaza at least in that block.
That is the old route of SR 89A, which itself is the old route of US 89A. I don’t think it was ever US 89. SR 89A still exists but now hops on a concurrency with I-17 at exit 337.
It's not a flashing yellow arrow, from what I can tell. Red arrow > Yellow Arrow > Green Arrow > ??.
https://goo.gl/maps/4GALxs593eNpSPv8A
Looks like a yellow arrow on the bottom, but can't find any evidence of it being used. Maybe it flashes at night? Hmm.
I think it might be split phased. Unless you saw for sure otherwise.
That would certainly make more sense, given that the other side only has one lane for all three movements. I don’t remember for sure - I was more focused on the tremendous thunderstorm that was coming through when I passed through here
I'd honestly be curious to see how well this works if they tried it in the states. Probably not well, but it would definitely be interesting. It seems to me like Japan actually sets up their intersections to have permissive turns with the dashed lines at intersections, rather than America where they just kind of half-ass them in last minute and rely on people's knowledge of the rules of the road to get them through.
What's also worth mentioning is that the waiting zones for some of those turns are curved. In the states, it's generally considered bad practice to keep your wheels turned to the left when making a permissive turn so you don't get forced into oncoming traffic if you're rear ended.
Also completely unrelated, but I like how Google is so detailed that it shows a horizontal traffic signal on Japanese Google Maps.
Japan 100% designs for permissive turns. The waiting boxes, the colored pavement, the green arrows at the end to catch anyone that doesn't make it...they've totally thought it through and, seeing it in person, I can confirm it's a great setup, even with two or more turn lanes.
The curved waiting zones make sense here as they don't generally design their turns with any positive offset (rare counter example here (https://goo.gl/maps/DwM7wR6sY72rL3ZV9)). Meaning, the medians are always to the right, no matter how wide. The curved waiting zones ensure that you pull out to an area where you can see traffic more easily. The double right turn boxes always have offset waiting lines too, so that one car doesn't block the view of another. It's all decently well designed. The whole issue with being rear-ended seems really odd to me. At least here, traffic that pulls into the right turn lanes is already slowing down, the chance of someone getting into the right turn lane and then ploughing full-speed into someone waiting seems really low. Especially at a speed high enough to cause traffic to go launching forward more than a meter at most.
Google Maps actually shows an incredible amount of detail in Japan. The horizontal traffic lights are great too, but they had all the extra detail (like exact roadway geometry) way before Google started launching that stuff in North America. It is really incredible, and one of the few reasons that I use Google Maps for navigation over here more than Waze...not just because it has more info, like street names, but it just shows more detail.
I think this was shared before, but not in this thread. I had been looking for this location, as someone had shared it a while back. But I hadn't been able to figure out where it was. Thank you for posting it.
I'd love to see it tried somewhere, but doubt any engineer has the courage to give it a shot.
The issue in Japan with turning traffic doesn't have anything to do with how many lanes there are, but actually oncoming traffic not stopping even after their light is red. Drivers here really push yellow lights, with many entering on red, even two or three seconds after it has come up. This isn't too big of a deal, as the green arrow comes on at the end, giving you plenty of time to wait a moment before finishing your turn. Still, some drivers really push the lights here far worse than anything I've seen anywhere in the US.
edit: fixed sentence missing words.
Great find. That is indeed a very unique setup, with the double supplemental left turn 5-section towers. I think I've seen that once or twice, but that's considering the entirety of the US. Particularly unusual for Missouri and Kansas where left-side supplemental signals aren't particularly common anyways. And the mix of signal displays is very odd! I can only think of one intersection with a mix like that, here in Des Moines, WA (https://goo.gl/maps/iEMkix313d1ZtKgr5).
Lost of potential, though! They could have added a flashing yellow arrow to the doghouse, and it could have ended up like this FYA/doghouse combo in MN:
https://goo.gl/maps/y1EVTe4XtsRTUmsX9
https://youtu.be/onyZQcgkMOw
Jake's example for the combo FYA & 5-section makes sense, given the characteristics of the depicted approach and the opposing approach being relatively minor (commercial center parking access) with likely modest volumes.
I am somewhat intrigued by the situation Hobart posted though. The depicted approach is left-shared left/thru-thru-thru, so that 5-section display over the shared lane is non-compliant. But it looks like the cross street has a wide median–the overall operation along FM 1535 appears to be split phased, and this particular signal appears to be running an overlap, so that gives it a little more leeway. It looks like this situation will disappear soon though, as the most recent Street View appears to be converting this overall intersection into something a bit more akin to a SPUI.
Really cool find. I actually had a pin saved on my Google Maps of one of the other double-left FYA signals in Lafayette. They definitely aren't afraid of dual permissive turns.
Couple other oddities in Lafayette: (1) they also are keen on double right turns with yield signs (here (https://goo.gl/maps/U4XqFVFJ9jNQ6G1w5) and here (https://goo.gl/maps/xREAdecUYQ6h94pA7) being examples), and (2) this double left turn (https://goo.gl/maps/Vqxk2nAe9xG5aQcq9) has an almost absurd amount of offset, even I'm not sure I would have used a yield there, visibility must be awful for the left-left turn lane.
Edit: forgot to mention, but I really like the supplemental signage used in Lafayette. Really helpful and to-the-point.
I noticed that too, even their very new left turn signals continue to use red orbs. It's definitely not MUTCD-compliant (unless there is split-phasing), and hasn't been since the 2009 MUTCD was released (plus a couple years for LADOT adoption, Lafayette adoption, and eventual incorporation into projects, all of which should have happened 10+ years ago).
I'm with you there, it is a very interesting combination of things. All except for the red-orb left turn signals I am a fan of, for sure. Why they've kept using those, I do not understand at all, especially with how long they've been non-compliant.
I also really like their road markings. These days it seems like some places are very inconsistent, like the road markings aren't done with much care or consistency. Lafayette seems to be very consistent in their design, everything seems to be kept up in good shape, they always paint the left turn lane with some offset to improve visibility and create a very nice island between the through and left turn lanes (example here (https://goo.gl/maps/Fw3SrC3uWx3PB3Mj8))....it's just all really well done.
I think this is how option lanes should be designed if possible. Split-phasing where there is no oncoming left seems kind of odd to me, even though it's the only option when most DOT's ban permissive turns with more than one lane.
Ironically given the Texas-style U-turn, this style of phasing with option lanes is probably most common in Texas.
The extremely rare examples of split-phasing here in Japan are like this, with no green arrows whatsoever. Obviously drivers are going to figure out what is going on within a few seconds, and drivers who regularly use the intersection already know the operations, but it seems like it might invite undue hesitation from drivers unfamiliar with the operation.
Great find! Clean and very new example. Very unusual for Ontario to install this, though I'm pretty sure at least one other exists somewhere else.
This is exactly the kind of scenario where I think double permissive turns should be acceptable: no oncoming left (excellent visibility), and relatively quiet approach.
I've been led to believe they are incredibly rare in Ontario and Quebec. However, out west, they are much more common. British Columbia has a half dozen examples I can think of. Alberta has a ton though almost all are in Edmonton (though they've fallen out of favor; it was the norm just ten years ago). Though sparsely populated, I believe Saskatchewan and Manitoba have quite a few examples too.
Works for me! Still yielding to pedestrians and vehicles.
Odd the "wait for green" sign was left up. Kind of sends the wrong message with a flashing yellow arrow.
Agreed, but I think it was there because the cross street had one side turn red before the other, so drivers saw most traffic stop and tried to jump their own red light.
Poking around GSV, this left turn in Montréal (https://www.google.com/maps/@45.5084184,-73.5618962,3a,41.7y,31.65h,83.66t/data=!3m7!1e1!3m5!1s7p0OHo37tF8q2OzNelX_IQ!2e0!5s20140401T000000!7i13312!8i6656?hl=en) used to be double permissive (L-LT) up till around the summer of 2014. It is now protected only with only 1 turning lane since then and when I was there on a Friday and Saturday, there were long queues and some split failures at this left turn.
Nice find! Never seen one in Quebec before, to be honest. I was assuming they were rare as none have been brought up here before.
I find it odd they'd remove the outside turn lane (except for buses) and change it to protected-only. Seems like it could still operate permissively as it stands.
Great find! Too bad it wasn't on better terms :-D. Though perhaps the driver going straight needs to use more caution. One driver screwing up can be offset by someone driving more defensively.
The setup is actually identical to the very first double permissive left that I ever encountered in Canada, turning left from Main St onto the Dunsmuir Viaduct in Vancouver (https://goo.gl/maps/AmirnCfvQrguUckx9).
Found another one in Montreal:
https://goo.gl/maps/GPgAUCjCtYXBgiJz5
It has an option lane like the other examples from Quebec.
I guess if it were up to this black Honda Accord (https://goo.gl/maps/xC4VYzPUsBZtduAYA), there wouldn't be any question that it qualifies!
I am actually willing to count this. It's really intriguing, I'm sure most places would have some kind of exclusive phasing for this approach instead of having it run concurrent with vehicular traffic.
It's almost like a purposeful version of a lane-split turn for a motorcyclist. Here in Japan, where like California it is also legal to ride between lanes of traffic, it's not unusual to be waiting to turn across traffic when a motorcyclist (usually scooter) will come up between traffic and wait next to you while you're also waiting to turn. It'll be a single lane turn (right turn in Japan), but it becomes a sort of double permissive turn with the motorcyclist also hanging out there in the middle waiting with you. As far as I can tell, that's basically what might happen in the SF example, although there is at least a designated cycle lane.
The turn lane queues on the triple lefts don't even appear they line up well with the receiving lane on the other side.
Indeed, the right turn lanes don't line up well at all. It's almost like you turn into the queue area, then go straight, and then make another slight right onto the receiving road.
It goes without saying that this would never work in the US, drivers would constantly end up in the wrong lane. And even for Japan, where drivers are substantially more aware of their surroundings than American or Canadian drivers, this is apparently a very intimidating intersection. Not least because it operated permissively, but also because of the huge neutral area (the area where turning traffic and through traffic cross over) that made it really hard to gauge when it was appropriate to, you know, 'go for it'. Which was certainly exacerbated by the very odd alignment of the turn lanes.
Dammit. Yeah, triple rights.
A bit of a weird one. I'd say that the bike left turn doesn't have to turn against car traffic, only against peds and oncoming bikes. If one were to ignore the oncoming bikes, this is like a left from one way to one way as the bikes make their left into the lane most adjacent to the curb on Fell. So really only the cars have to make a permissive left against traffic (opposing vehicles making the right from Scott to Fell).
A very unique example!
Thank you for posting! This is one of the more interesting ones I've seen lately.
Some of the GSV imagery seems to suggest that some drivers were already turning left from the through lane (https://maps.app.goo.gl/uWQbYwcdcGNg927J8). Or possibly this was a permitted movement, and I just can't find any signage to prove it.
The new far-left signal is great. While I'm a proponent of making this standard for all approaches, it's nice they added it here as before, there was no visible signal while waiting.
While this is cool to see, especially with the markings in the intersection showing where drivers to wait when turning, the fact that NB Freeport is still allowed turn left onto Morrissey Blvd is quite odd. I would think detouring those cars via Mill or Everdean would create less of that unusual left turn overlap situation occurring in the video.
As an aside, I assume this is the only double permissive FYA setup in Massachusetts.
Question: Do you think dual permissive turns should be allowed?
Option 1: Yes
votes: 59
Option 2: No
votes: 35
Option 3: Cat
votes: 22
Title: Double left turns with permissive phasing
Post by: jakeroot on December 14, 2015, 02:01:17 AM
Post by: jakeroot on December 14, 2015, 02:01:17 AM
I have brought this topic up so many times in the past, I must appear to be obsessed with these things now. I certainly don't want it to look like that, but dual permissive left turns have to be one of the rarest forms of traffic control in the business, far, far less common than even the modern roundabout. I'm fairly certain that they're limited to North America and maybe China.
I remember seeing my first double permissive left in Colorado Springs when I was maybe 11 or 12. The exit from my grandparent's neighborhood leads to a signal at Chestnut St and Garden of the Gods Road, which is a permissive double left. I always thought this was strange, simply because I had never seen this before in Washington or BC, and also because so many single lane turns in my area are protected-only, it boggled my mind how there could be two lanes that could yield. Anyways, years later, on a trip through Edmonton, Alberta, I encountered a slew of these double permissive turns. Once again, I was mesmerized by them. The capacity of the turn seems to explode when there's two lanes yielding. Very rarely sat and waited to turn up there. I have been impressed (read: obsessed) ever since.
So, the purpose of this thread? I'd like to know your thoughts on these things. Do you think they're a bad idea? Do you wish they were used more? You're welcome to list where these things are located if you know of any (I've asked on other threads already, but for continuity, it might be better to "relist" them here). No need to point out Tucson, AZ or Richardson/McKinney, TX, as they're already quite well known for theirs.
Quite a few state DOT's do not permit their use (WSDOT's MUTCD states, very plainly, that permissive lefts are not allowed "on intersection approaches that have dual left-turn lanes"). But, on roads not maintained by the state, these things are fair game. Locally, Seattle has a couple that I know of, Kennewick (WA) has at least two or three, and Silverdale (WA) used to have one before it was removed. Federal Way (WA) intends to install one in the future, but nothing official has come around (short of a short snippet (http://goo.gl/jQObb5) (see p. 25) from the chief engineer a few months ago)
I've run over the inherent ups and downs over the years:
+ increased capacity
+ more green time for through traffic
+ speeds up travel times? (I suppose these three are all connected in some way)
+ higher level of functionality (protected only some times, permissive only others) with FYAs
- potentially increased danger because there's simply a higher chance of something going wrong
- driver's may not understand the flashing yellow arrow?
- potentially reduced visibility for inside lane's car, depending on where the outside lane's car is waiting
Here's an image of a typical FYA setup (James St at 6th Ave, Seattle):
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F9TJxDfS.png&hash=ef332dc58fd153983f86f1f0c7f2d4c2b6c8e9a1)
I remember seeing my first double permissive left in Colorado Springs when I was maybe 11 or 12. The exit from my grandparent's neighborhood leads to a signal at Chestnut St and Garden of the Gods Road, which is a permissive double left. I always thought this was strange, simply because I had never seen this before in Washington or BC, and also because so many single lane turns in my area are protected-only, it boggled my mind how there could be two lanes that could yield. Anyways, years later, on a trip through Edmonton, Alberta, I encountered a slew of these double permissive turns. Once again, I was mesmerized by them. The capacity of the turn seems to explode when there's two lanes yielding. Very rarely sat and waited to turn up there. I have been impressed (read: obsessed) ever since.
So, the purpose of this thread? I'd like to know your thoughts on these things. Do you think they're a bad idea? Do you wish they were used more? You're welcome to list where these things are located if you know of any (I've asked on other threads already, but for continuity, it might be better to "relist" them here). No need to point out Tucson, AZ or Richardson/McKinney, TX, as they're already quite well known for theirs.
Quite a few state DOT's do not permit their use (WSDOT's MUTCD states, very plainly, that permissive lefts are not allowed "on intersection approaches that have dual left-turn lanes"). But, on roads not maintained by the state, these things are fair game. Locally, Seattle has a couple that I know of, Kennewick (WA) has at least two or three, and Silverdale (WA) used to have one before it was removed. Federal Way (WA) intends to install one in the future, but nothing official has come around (short of a short snippet (http://goo.gl/jQObb5) (see p. 25) from the chief engineer a few months ago)
I've run over the inherent ups and downs over the years:
+ increased capacity
+ more green time for through traffic
+ speeds up travel times? (I suppose these three are all connected in some way)
+ higher level of functionality (protected only some times, permissive only others) with FYAs
- potentially increased danger because there's simply a higher chance of something going wrong
- driver's may not understand the flashing yellow arrow?
- potentially reduced visibility for inside lane's car, depending on where the outside lane's car is waiting
Here's an image of a typical FYA setup (James St at 6th Ave, Seattle):
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F9TJxDfS.png&hash=ef332dc58fd153983f86f1f0c7f2d4c2b6c8e9a1)
Title: Re: Dual Left Permissive Turns (FYA or Doghouse)
Post by: Ace10 on December 14, 2015, 02:50:35 AM
Post by: Ace10 on December 14, 2015, 02:50:35 AM
I grew up learning how to drive on the Gulf Coast in Mississippi, where there are apparently still at least three intersections with dual permissive lefts (which are at (1) Popps Ferry Rd and Cedar Lake Blvd in Biloxi (https://www.google.com/maps/@30.4427198,-88.9340841,3a,25.2y,100.48h,94.83t/data=!3m7!1e1!3m5!1s_m5f6Xth4tFpZ7ip5RL-iQ!2e0!6s%2F%2Fgeo2.ggpht.com%2Fcbk%3Fpanoid%3D_m5f6Xth4tFpZ7ip5RL-iQ%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D349.53455%26pitch%3D0!7i13312!8i6656), (2) MS 605 (Cowan Rd) and Pass Rd in Gulfport (https://www.google.com/maps/@30.3988569,-89.0264069,3a,75y,237.5h,73t/data=!3m6!1e1!3m4!1shOAIdXHebJXgkPDDAWWhtQ!2e0!7i13312!8i6656), and (3) WB Rodriguez St to SB I-110 in D'Iberville (https://www.google.com/maps/@30.4299739,-88.8952032,3a,51.4y,328.8h,78.59t/data=!3m6!1e1!3m4!1sePRTO65c04J-24bpTz_XWA!2e0!7i13312!8i6656) (see lane markings)). Popps Ferry/Cedar Lake's dual permissive lefts are only for eastbound Popps Ferry traffic turning left onto northbound Cedar Lake, but MS 605/Pass Rd's dual permissive lefts are for E/W Pass Rd traffic turning left onto N/S MS 605.
#3 (Rodriguez & SB I-110) is unique in that there are dual permissive lefts, but the outside (rightmost) left turn lane is also a through lane. The rightmost lane is the only dedicated through lane. #1 (Cedar Lake & Popps Ferry) used to have this setup when I first began driving but it's been changed so that both left turn lanes are dedicated and the right lane is optional through/right turn.
For the second intersection (MS 605 & Pass Rd), I don't know why all four directions don't have dual permissive lefts. It's very flat and straight at that intersection. If one road can have it, why not both? Especially the one with less through traffic? Also interestingly there is only one doghouse per direction on Pass Rd, but two left turn lanes. I have a feeling this intersection was widened a while back and maybe the old signals were kept.
Since then, I think the only other place I've seen them is Duluth, Minnesota, but since Minnesota is the place I think I've seen the most FYAs outside of Oregon and Washington, there are probably more lurking about.
I like them, particularly if there is a high volume of left-turning traffic and perhaps not as much through traffic. There are a few intersections west of Portland - one namely is Baseline Rd and Cornelius Pass Rd, where traffic turning left from E/W Baseline onto N/S Cornelius Pass face a double protected-only arrow. I've been at that intersection enough times where through traffic on Baseline is clear and other traffic could easily turn left, but they're stuck at the red arrow.
The only con I can say I've experienced was the reduced visibility if you're in the inside (left-most) left turn lane. If I'm behind a long line of cars that have just begun turning on the permissive movement, unless I have clear shot of (lack of) opposing traffic, I'll lag a little behind until I'm sure the way is clear before I turn. If there's another lane to the right of me making the same turn, I'd either have to potentially wait longer for visual clearance or trust the person to the right of me to also yield, else an accident would ensue.
#3 (Rodriguez & SB I-110) is unique in that there are dual permissive lefts, but the outside (rightmost) left turn lane is also a through lane. The rightmost lane is the only dedicated through lane. #1 (Cedar Lake & Popps Ferry) used to have this setup when I first began driving but it's been changed so that both left turn lanes are dedicated and the right lane is optional through/right turn.
For the second intersection (MS 605 & Pass Rd), I don't know why all four directions don't have dual permissive lefts. It's very flat and straight at that intersection. If one road can have it, why not both? Especially the one with less through traffic? Also interestingly there is only one doghouse per direction on Pass Rd, but two left turn lanes. I have a feeling this intersection was widened a while back and maybe the old signals were kept.
Since then, I think the only other place I've seen them is Duluth, Minnesota, but since Minnesota is the place I think I've seen the most FYAs outside of Oregon and Washington, there are probably more lurking about.
I like them, particularly if there is a high volume of left-turning traffic and perhaps not as much through traffic. There are a few intersections west of Portland - one namely is Baseline Rd and Cornelius Pass Rd, where traffic turning left from E/W Baseline onto N/S Cornelius Pass face a double protected-only arrow. I've been at that intersection enough times where through traffic on Baseline is clear and other traffic could easily turn left, but they're stuck at the red arrow.
The only con I can say I've experienced was the reduced visibility if you're in the inside (left-most) left turn lane. If I'm behind a long line of cars that have just begun turning on the permissive movement, unless I have clear shot of (lack of) opposing traffic, I'll lag a little behind until I'm sure the way is clear before I turn. If there's another lane to the right of me making the same turn, I'd either have to potentially wait longer for visual clearance or trust the person to the right of me to also yield, else an accident would ensue.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: roadman65 on December 14, 2015, 03:25:32 AM
Post by: roadman65 on December 14, 2015, 03:25:32 AM
Florida did have it in Kissimmee, FL on John Young Parkway and Carroll Street. It lasted for a few months before Kissimmee (in Florida the state does not at all maintain or operate signals) realized that it was two lanes turning left with one doghouse for both lanes. So in essence they added two left turn signals and made the turn on green arrow only.
This all happened when JYP was made to connect Kissimmee with Hunters Creek back in the early 90's.
This all happened when JYP was made to connect Kissimmee with Hunters Creek back in the early 90's.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: cl94 on December 14, 2015, 11:11:27 AM
Post by: cl94 on December 14, 2015, 11:11:27 AM
I'm not a big fan of them. With permissive movements especially, cars don't always follow a nice, curved path while turning due to other factors. Have 2 cars trying to make the turn and I see the risk for sideswiping.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: froggie on December 14, 2015, 11:43:54 AM
Post by: froggie on December 14, 2015, 11:43:54 AM
Ace10 beat me to the Mississippi Coast examples.
MnDOT policy on dual left turn lanes is that they must be protected-only.
MnDOT policy on dual left turn lanes is that they must be protected-only.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: freebrickproductions on December 14, 2015, 12:52:42 PM
Post by: freebrickproductions on December 14, 2015, 12:52:42 PM
Several around here in Huntsville, AL. I'll post them in a little bit.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: JCinSummerfield on December 14, 2015, 01:08:19 PM
Post by: JCinSummerfield on December 14, 2015, 01:08:19 PM
I think if you're going to have them, you should at least have FYA for permissive left turns.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: briantroutman on December 14, 2015, 01:38:51 PM
Post by: briantroutman on December 14, 2015, 01:38:51 PM
As much as I hate to cater to the lowest common denominator of uneducated driver, I think dual permissive left turns (particularly with a flashing left arrow) may be a bridge too far.
There are just too many minuses:
- too many drivers already lack lane discipline even in protected multi-lane turns
- difficulty in making a judgement due to alternating vehicular and pedestrian traffic–or worse, reckless disregard for pedestrians, oncoming vehicles, or both
- general unfamiliarity with flashing yellow arrow
etc.
Any one of these issues already exist in other situations, but I think having all of these (and more) combined in one situation tilts the scales toward the arrangement being not recommendable, in my opinion.
There are just too many minuses:
- too many drivers already lack lane discipline even in protected multi-lane turns
- difficulty in making a judgement due to alternating vehicular and pedestrian traffic–or worse, reckless disregard for pedestrians, oncoming vehicles, or both
- general unfamiliarity with flashing yellow arrow
etc.
Any one of these issues already exist in other situations, but I think having all of these (and more) combined in one situation tilts the scales toward the arrangement being not recommendable, in my opinion.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: cl94 on December 14, 2015, 01:55:53 PM
Post by: cl94 on December 14, 2015, 01:55:53 PM
Quote from: briantroutman on December 14, 2015, 01:38:51 PM
- too many drivers already lack lane discipline even in protected multi-lane turns
Yeah. I get cut off at least once a week at a double protected left/right because people either turn into the other lane or cross the dividing line while making the turn. People don't understand how to be safe in protected left turns. Why add more dangerous elements?
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on December 14, 2015, 02:14:31 PM
Post by: jakeroot on December 14, 2015, 02:14:31 PM
Quote from: cl94 on December 14, 2015, 01:55:53 PMQuote from: briantroutman on December 14, 2015, 01:38:51 PM
- too many drivers already lack lane discipline even in protected multi-lane turns
Yeah. I get cut off at least once a week at a double protected left/right because people either turn into the other lane or cross the dividing line while making the turn. People don't understand how to be safe in protected left turns. Why add more dangerous elements?
That might be a regional thing. Like basically any traffic control device, there are parts of the country where it works better than others. There are more than a few double left turns near me, and I really can't recall being cut off before. As long as the lane lines are delineated well throughout the intersection, I don't think it's as big of a problem as it may appear to be.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: busman_49 on December 14, 2015, 02:56:36 PM
Post by: busman_49 on December 14, 2015, 02:56:36 PM
The only one I can think off that I've seen is in Stow, Ohio. The first time I saw it, it was a WTF moment for me, only because I didn't realize that sort of thing existed.
https://www.google.com/maps/@41.1666559,-81.4406866,3a,75y,94.34h,72.57t/data=!3m6!1e1!3m4!1sJNPccP0xB1x38IEhpUKcPw!2e0!7i13312!8i6656!6m1!1e1
https://www.google.com/maps/@41.1666559,-81.4406866,3a,75y,94.34h,72.57t/data=!3m6!1e1!3m4!1sJNPccP0xB1x38IEhpUKcPw!2e0!7i13312!8i6656!6m1!1e1
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: riiga on December 14, 2015, 03:22:49 PM
Post by: riiga on December 14, 2015, 03:22:49 PM
It's certainly a very intriguing concept, but they both violate the Vienna Convention and most probably lead to more accidents than a regular protected turn signal for a very negligable capacity improvement. As such I imagine none will ever be built here or in the rest of Europe.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: UCFKnights on December 14, 2015, 05:52:09 PM
Post by: UCFKnights on December 14, 2015, 05:52:09 PM
I've only seen 1 or 2 in my life but I really liked them, especially now with FYAs. It seems lilke an easy way to add quite a bit of traffic flow improvements. I see everyone here is claiming way too dangerous... I'd like to see some data on this. anyone have that available?
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: cl94 on December 14, 2015, 06:04:21 PM
Post by: cl94 on December 14, 2015, 06:04:21 PM
Quote from: UCFKnights on December 14, 2015, 05:52:09 PM
I've only seen 1 or 2 in my life but I really liked them, especially now with FYAs. It seems lilke an easy way to add quite a bit of traffic flow improvements. I see everyone here is claiming way too dangerous... I'd like to see some data on this. anyone have that available?
I'm going by how people drive on dual left turns in the midwest. I've seen too many accidents happen due to people leaving their lane while turning.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: tradephoric on December 14, 2015, 06:48:40 PM
Post by: tradephoric on December 14, 2015, 06:48:40 PM
Studies have found that a significant percentage of drivers don't look to see if there are pedestrians in the crosswalk when making a permissive left (drivers are focused on gaps in opposing traffic). At a single permissive left-turn, drivers have the opportunity to swerve around a pedestrian they didn't initially see. At a dual permissive left-turn, drivers may not be able to swerve since a vehicle would very likely be next to them (or they do swerve to avoid the pedestrian and sideswipe the vehicle next to them... potentially causing that vehicle to lose control and run into the sidewalk). It just sounds like a bad scenario.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: 1995hoo on December 14, 2015, 07:29:49 PM
Post by: 1995hoo on December 14, 2015, 07:29:49 PM
I can't say I ever recall seeing dual permissive left turns (doesn't mean I haven't seen one, just that I do not ever remember it). Given that VDOT is religious about prohibiting right turns on red from any lane other than the curb lane, I highly doubt they'd ever allow dual permissive lefts.
The thing this thread makes me think of is the thread a few months ago about whether it's OK, or a good idea, to pull out into the intersection while waiting to make a permissive left turn. In places where that practice is routine, I could see permissive dual lefts being a problem because of visibility issues. It can be hard enough to see to go left when there's one large truck or SUV pulled out waiting to turn opposite you. If there were two such vehicles, it would likely be considerably more difficult for the driver in the right-hand lane of the two left-turn lanes to see oncoming traffic, unless you had some sort of median or other way of staggering the turn lanes away from the thru lanes (which is uncommon in Virginia, at least).
The thing this thread makes me think of is the thread a few months ago about whether it's OK, or a good idea, to pull out into the intersection while waiting to make a permissive left turn. In places where that practice is routine, I could see permissive dual lefts being a problem because of visibility issues. It can be hard enough to see to go left when there's one large truck or SUV pulled out waiting to turn opposite you. If there were two such vehicles, it would likely be considerably more difficult for the driver in the right-hand lane of the two left-turn lanes to see oncoming traffic, unless you had some sort of median or other way of staggering the turn lanes away from the thru lanes (which is uncommon in Virginia, at least).
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: UCFKnights on December 14, 2015, 08:09:20 PM
Post by: UCFKnights on December 14, 2015, 08:09:20 PM
Quote from: 1995hoo on December 14, 2015, 07:29:49 PMI'm curious if there exists a permissive turn left lane only? That would solve a lot of the complaints mentioned here, and I know around here, there are a number of right turn on red right lane only and they seem to operate without issue. Well, we have a few right turn on red from 2 right turn lanes and they also operate seemingly fine and help deal with traffic congestion.
I can't say I ever recall seeing dual permissive left turns (doesn't mean I haven't seen one, just that I do not ever remember it). Given that VDOT is religious about prohibiting right turns on red from any lane other than the curb lane, I highly doubt they'd ever allow dual permissive lefts.
The thing this thread makes me think of is the thread a few months ago about whether it's OK, or a good idea, to pull out into the intersection while waiting to make a permissive left turn. In places where that practice is routine, I could see permissive dual lefts being a problem because of visibility issues. It can be hard enough to see to go left when there's one large truck or SUV pulled out waiting to turn opposite you. If there were two such vehicles, it would likely be considerably more difficult for the driver in the right-hand lane of the two left-turn lanes to see oncoming traffic, unless you had some sort of median or other way of staggering the turn lanes away from the thru lanes (which is uncommon in Virginia, at least).
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on December 14, 2015, 09:51:20 PM
Post by: jakeroot on December 14, 2015, 09:51:20 PM
Quote from: UCFKnights on December 14, 2015, 08:09:20 PMQuote from: 1995hoo on December 14, 2015, 07:29:49 PM
I can't say I ever recall seeing dual permissive left turns (doesn't mean I haven't seen one, just that I do not ever remember it). Given that VDOT is religious about prohibiting right turns on red from any lane other than the curb lane, I highly doubt they'd ever allow dual permissive lefts.
The thing this thread makes me think of is the thread a few months ago about whether it's OK, or a good idea, to pull out into the intersection while waiting to make a permissive left turn. In places where that practice is routine, I could see permissive dual lefts being a problem because of visibility issues. It can be hard enough to see to go left when there's one large truck or SUV pulled out waiting to turn opposite you. If there were two such vehicles, it would likely be considerably more difficult for the driver in the right-hand lane of the two left-turn lanes to see oncoming traffic, unless you had some sort of median or other way of staggering the turn lanes away from the thru lanes (which is uncommon in Virginia, at least).
I'm curious if there exists a permissive turn left lane only?
But wouldn't everyone just stay in the lane that permits turns? You'd have a pretty uneven lane balance I'd think.
Quote from: tradephoric on December 14, 2015, 06:48:40 PM
Studies have found that a significant percentage of drivers don't look to see if there are pedestrians in the crosswalk when making a permissive left (drivers are focused on gaps in opposing traffic). At a single permissive left-turn, drivers have the opportunity to swerve around a pedestrian they didn't initially see. At a dual permissive left-turn, drivers may not be able to swerve since a vehicle would very likely be next to them (or they do swerve to avoid the pedestrian and sideswipe the vehicle next to them... potentially causing that vehicle to lose control and run into the sidewalk). It just sounds like a bad scenario.
A pretty common scenario with permissive turns, number of lanes irrelevant, is having the FYA go red when the pedestrian walk signal is green (Bellevue, WA does this at many of their FYAs). This might solve that problem.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: 1995hoo on December 14, 2015, 10:42:43 PM
Post by: 1995hoo on December 14, 2015, 10:42:43 PM
Quote from: jakeroot on December 14, 2015, 09:51:20 PMQuote from: UCFKnights on December 14, 2015, 08:09:20 PMQuote from: 1995hoo on December 14, 2015, 07:29:49 PM
I can't say I ever recall seeing dual permissive left turns (doesn't mean I haven't seen one, just that I do not ever remember it). Given that VDOT is religious about prohibiting right turns on red from any lane other than the curb lane, I highly doubt they'd ever allow dual permissive lefts.
The thing this thread makes me think of is the thread a few months ago about whether it's OK, or a good idea, to pull out into the intersection while waiting to make a permissive left turn. In places where that practice is routine, I could see permissive dual lefts being a problem because of visibility issues. It can be hard enough to see to go left when there's one large truck or SUV pulled out waiting to turn opposite you. If there were two such vehicles, it would likely be considerably more difficult for the driver in the right-hand lane of the two left-turn lanes to see oncoming traffic, unless you had some sort of median or other way of staggering the turn lanes away from the thru lanes (which is uncommon in Virginia, at least).
I'm curious if there exists a permissive turn left lane only?
But wouldn't everyone just stay in the lane that permits turns? You'd have a pretty uneven lane balance I'd think.
....
That's what happens here with dual right turns. Everyone who lives around here knows that more than 99% of the time there'll be a sign prohibiting right on red from anywhere but the far right lane, so almost everyone will use only the far right lane unless the light is already green.
(I say "more than 99% of the time" because I can readily think of one light that doesn't have this restriction posted–the dual right turn from westbound Huntington Avenue to northbound Telegraph Road just south of the Beltway. Also, oddly, where there are dual left-turn lanes and a left-on-red situation, I've never seen a sign restricting lefts on red to the far left lane, although I have seen a "No Turn on Red" sign at a left-on-red spot.)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: UCFKnights on December 14, 2015, 11:20:11 PM
Post by: UCFKnights on December 14, 2015, 11:20:11 PM
Quote from: jakeroot on December 14, 2015, 09:51:20 PMWhile I'm sure the lane balance would no longer be even, in the dual right turn lanes around here, people will still use the left of them when the right one is congested and its clear they will not get to go before the light changes anyways. You do want the lanes to not be exactly balanced as the capacity isn't quite equal o the lanes. In this case, it'd likely end up more balanced then the right lane scenario as after the light turns red, people will try to balance out the other lane during the entire red phase.Quote from: UCFKnights on December 14, 2015, 08:09:20 PMQuote from: 1995hoo on December 14, 2015, 07:29:49 PM
I can't say I ever recall seeing dual permissive left turns (doesn't mean I haven't seen one, just that I do not ever remember it). Given that VDOT is religious about prohibiting right turns on red from any lane other than the curb lane, I highly doubt they'd ever allow dual permissive lefts.
The thing this thread makes me think of is the thread a few months ago about whether it's OK, or a good idea, to pull out into the intersection while waiting to make a permissive left turn. In places where that practice is routine, I could see permissive dual lefts being a problem because of visibility issues. It can be hard enough to see to go left when there's one large truck or SUV pulled out waiting to turn opposite you. If there were two such vehicles, it would likely be considerably more difficult for the driver in the right-hand lane of the two left-turn lanes to see oncoming traffic, unless you had some sort of median or other way of staggering the turn lanes away from the thru lanes (which is uncommon in Virginia, at least).
I'm curious if there exists a permissive turn left lane only?
But wouldn't everyone just stay in the lane that permits turns? You'd have a pretty uneven lane balance I'd think.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: tradephoric on December 14, 2015, 11:49:09 PM
Post by: tradephoric on December 14, 2015, 11:49:09 PM
Quote from: jakeroot on December 14, 2015, 09:51:20 PM
A pretty common scenario with permissive turns, number of lanes irrelevant, is having the FYA go red when the pedestrian walk signal is green (Bellevue, WA does this at many of their FYAs). This might solve that problem.
The low compliance rate among pedestrians can make this type of setup more harmful then helpful. It's conditioning drivers not to look for pedestrians during the permissive phase even though pedestrians may very well be present (since a pedestrian may simply chose not to push the pushbutton). There is a 2001 study from Windsor, Ontario where the pushbutton was actuated in only 32% of the cycles where a pedestrian crossed the street.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: roadfro on December 15, 2015, 01:01:40 AM
Post by: roadfro on December 15, 2015, 01:01:40 AM
Quote from: jakeroot on December 14, 2015, 09:51:20 PM
A pretty common scenario with permissive turns, number of lanes irrelevant, is having the FYA go red when the pedestrian walk signal is green (Bellevue, WA does this at many of their FYAs). This might solve that problem.
I don't think I've ever seen this... It also seems that the capacity of the PPLT would be reduced considerably in such a case where this is done.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on December 15, 2015, 02:06:06 AM
Post by: jakeroot on December 15, 2015, 02:06:06 AM
Quote from: roadfro on December 15, 2015, 01:01:40 AMQuote from: jakeroot on December 14, 2015, 09:51:20 PM
A pretty common scenario with permissive turns, number of lanes irrelevant, is having the FYA go red when the pedestrian walk signal is green (Bellevue, WA does this at many of their FYAs). This might solve that problem.
I don't think I've ever seen this... It also seems that the capacity of the PPLT would be reduced considerably in such a case where this is done.
Sorry, should have been more specific. I have witnessed this in Bellevue, WA.
One of Bellevue's engineers, Mark Poch, gave a presentation a few years ago, and there's a snippet from that powerpoint, which I have seen many times implemented in Bellevue, which suggests eliminating the permissive phase during walk signals:
Quote
How? SCATS "Ped Minus Left" Feature
- Omit permissive portion of pro/per when the crosswalk has a walk or flashing don't walk indication
Here's the whole presentation: http://goo.gl/sqg5qV. Page 19 has that quote on it, followed by a bunch of examples.
Quote from: UCFKnights on December 14, 2015, 05:52:09 PM
I've only seen 1 or 2 in my life but I really liked them, especially now with FYAs. It seems lilke an easy way to add quite a bit of traffic flow improvements. I see everyone here is claiming way too dangerous... I'd like to see some data on this. anyone have that available?
Exact data? Not really much. But the Virginia DOT (I cited this earlier) collected statements (http://goo.gl/jQObb5) from different agencies about their experiences with flashing yellow arrows, and some of them noted their uses with double permissive lefts:
Kennewick, Washington:
QuoteIt is not necessarily true that two lanes require Protected Only phasing. We run two locations like that. Our first location was turned on December 20th, 2004. It now serves a Home Depot, Walgreen's, Starbuck's, Pet Smart, and a few other small shops while the other side is single turn lane and serves Wal‐Mart, Burger King, Best Western, McDonalds and a gas station. This setup works fine because the two lanes both have clear vision of oncoming traffic, the opposing traffic is random arrival, and has adequate gaps. The two‐lanes were needed for storage due to [its] close proximity to a US Highway. Both turn lanes get used regularly and simultaneous traffic turning from the two lanes is not uncommon. I checked statistics and the actual left turn on the dual lane side gets triggered 20% of cycles or less. The Wal‐mart side gets triggered about 50% of the time through the peak hours.
Boulder, Colorado:
QuoteActually we've had good success with using Protected/Permissive phasing (by time of day) on dual left‐turn lane approaches. We are certainly not the only community in Colorado to do this either. I've yet to see any data that supports the premise that multiple left‐turn lanes requires protected only phasing. I've always considered that to be "Folklore".
Richardson, Texas (by way of Las Vegas):
QuoteAllow me to add credence to it being "Folklore" that dual lefts require protected only. When I was starting my municipal traffic engineering career in Richardson (TX) in the early 1980's, dual left‐turn lanes were the BIG NEW THING. We went ahead and built signals at all of our major‐crossing‐major intersections having dual left turns with 5‐section left‐turn heads, and they almost all ran PPLT 24x7x365. The drivers became accustomed to it, and didn't crash (at a too‐high rate). You can Google Street View just about any major arterial intersection in Richardson today, and you'll see this practice survives 30 years on.
The quotes start on page 64 according to the PDF, though the page number on the bottom is 25.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Tom958 on December 15, 2015, 06:59:04 AM
Post by: Tom958 on December 15, 2015, 06:59:04 AM
Quote from: roadman65 on December 14, 2015, 03:25:32 AM
Florida did have it in Kissimmee, FL on John Young Parkway and Carroll Street. It lasted for a few months before Kissimmee (in Florida the state does not at all maintain or operate signals) realized that it was two lanes turning left with one doghouse for both lanes. So in essence they added two left turn signals and made the turn on green arrow only.
There's one near my house in Gwinnett County, GA (https://www.google.com/maps/@33.9553145,-84.0567781,3a,75y,42.57h,78.28t/data=!3m6!1e1!3m4!1sp2dOn2RfYlSyvAAlqPFRSg!2e0!7i13312!8i6656). It's an anomaly, AFAIK, but it's been like this for decades, even as FYA's have started to appear nearby. I hope it remains as is-- I've never had a problem with it. I guess that's mainly because straight-through traffic between Cruse Road and Marathon Blvd is very light.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: UCFKnights on December 15, 2015, 09:43:31 AM
Post by: UCFKnights on December 15, 2015, 09:43:31 AM
Quote from: jakeroot on December 15, 2015, 02:06:06 AMInteresting.... another one I thought was pretty interesting and would like to see play out:Quote from: roadfro on December 15, 2015, 01:01:40 AMQuote from: jakeroot on December 14, 2015, 09:51:20 PM
A pretty common scenario with permissive turns, number of lanes irrelevant, is having the FYA go red when the pedestrian walk signal is green (Bellevue, WA does this at many of their FYAs). This might solve that problem.
I don't think I've ever seen this... It also seems that the capacity of the PPLT would be reduced considerably in such a case where this is done.
Sorry, should have been more specific. I have witnessed this in Bellevue, WA.
One of Bellevue's engineers, Mark Poch, gave a presentation a few years ago, and there's a snippet from that powerpoint, which I have seen many times implemented in Bellevue, which suggests eliminating the permissive phase during walk signals:Quote
How? SCATS "Ped Minus Left" Feature
- Omit permissive portion of pro/per when the crosswalk has a walk or flashing don't walk indication
Here's the whole presentation: http://goo.gl/sqg5qV. Page 19 has that quote on it, followed by a bunch of examples.Quote from: UCFKnights on December 14, 2015, 05:52:09 PM
I've only seen 1 or 2 in my life but I really liked them, especially now with FYAs. It seems lilke an easy way to add quite a bit of traffic flow improvements. I see everyone here is claiming way too dangerous... I'd like to see some data on this. anyone have that available?
Exact data? Not really much. But the Virginia DOT (I cited this earlier) collected statements (http://goo.gl/jQObb5) from different agencies about their experiences with flashing yellow arrows, and some of them noted their uses with double permissive lefts:
Kennewick, Washington:QuoteIt is not necessarily true that two lanes require Protected Only phasing. We run two locations like that. Our first location was turned on December 20th, 2004. It now serves a Home Depot, Walgreen's, Starbuck's, Pet Smart, and a few other small shops while the other side is single turn lane and serves Wal‐Mart, Burger King, Best Western, McDonalds and a gas station. This setup works fine because the two lanes both have clear vision of oncoming traffic, the opposing traffic is random arrival, and has adequate gaps. The two‐lanes were needed for storage due to [its] close proximity to a US Highway. Both turn lanes get used regularly and simultaneous traffic turning from the two lanes is not uncommon. I checked statistics and the actual left turn on the dual lane side gets triggered 20% of cycles or less. The Wal‐mart side gets triggered about 50% of the time through the peak hours.
Boulder, Colorado:QuoteActually we've had good success with using Protected/Permissive phasing (by time of day) on dual left‐turn lane approaches. We are certainly not the only community in Colorado to do this either. I've yet to see any data that supports the premise that multiple left‐turn lanes requires protected only phasing. I've always considered that to be "Folklore".
Richardson, Texas (by way of Las Vegas):QuoteAllow me to add credence to it being "Folklore" that dual lefts require protected only. When I was starting my municipal traffic engineering career in Richardson (TX) in the early 1980's, dual left‐turn lanes were the BIG NEW THING. We went ahead and built signals at all of our major‐crossing‐major intersections having dual left turns with 5‐section left‐turn heads, and they almost all ran PPLT 24x7x365. The drivers became accustomed to it, and didn't crash (at a too‐high rate). You can Google Street View just about any major arterial intersection in Richardson today, and you'll see this practice survives 30 years on.
The quotes start on page 64 according to the PDF, though the page number on the bottom is 25.
Quote
For single left‐turn lanes, I rarely find that the signal needs protection 24/7/365. Herein lies one of the
wonderful applications of the FYA. It affords the ability to run the needed indication according to the
conditions. For duals, we have seen permitted operation and have just discovered the NCDOT is
experimenting with them. We have one location out of 212 that we think may lend itself to this
operation. Like the previous point, rarely do we need duals in the overnight hours. I think the
technology will evolve that we can vary the duals by TOD. Therefore the outside turn lane would run
with a standard three section head and the inside with a 4 section FYA. During times when the duals
are needed, the FYA would be extinguished and full protection afforded. Later, when appropriate the
FYA activated and the outside lane closed with a blankout sign. The three sectionwould stay red
and the blankout sign would flash if the detector for that lane became active.
Point here, as technology changes we should seriously examine the past paradigms to see whether
application of this technology can provide better service to our customers without sacrificing safety. By
displaying the correct design for the conditions, we are also most likely to gain the best compliance from
our roadway users and generate respect for the work we do. Let's also remember that most signals
are designed to handle the peak hour load which by logic of the K factor represents only 20% of our
users. What about the other 80%?
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on December 16, 2015, 08:13:39 PM
Post by: jakeroot on December 16, 2015, 08:13:39 PM
I added a poll. A bit late, but it doesn't hurt.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Super Mateo on December 16, 2015, 08:41:25 PM
Post by: Super Mateo on December 16, 2015, 08:41:25 PM
Quote from: cl94 on December 14, 2015, 06:04:21 PMQuote from: UCFKnights on December 14, 2015, 05:52:09 PM
I've only seen 1 or 2 in my life but I really liked them, especially now with FYAs. It seems lilke an easy way to add quite a bit of traffic flow improvements. I see everyone here is claiming way too dangerous... I'd like to see some data on this. anyone have that available?
I'm going by how people drive on dual left turns in the midwest. I've seen too many accidents happen due to people leaving their lane while turning.
In the south suburbs of Chicago, the dotted line indicating where to turn is usually ignored. The drivers in the outer lane frequently tend to cross it, varying from just half a tire width to the entire car being inside the curve. They often don't allow the inner lane enough room and it often leads to the inner cars either hitting the median or causing the end of the turn to be extra sharp. I will not use the left/inner lane of a double left anymore because it has become that bad.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: MASTERNC on December 16, 2015, 09:56:18 PM
Post by: MASTERNC on December 16, 2015, 09:56:18 PM
I remember seeing one in Michigan (at least I think it was) about 12 years ago. It wasn't until April that I saw another one, this one in Castle Rock, CO.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: cl94 on December 17, 2015, 10:04:22 AM
Post by: cl94 on December 17, 2015, 10:04:22 AM
Quote from: Super Mateo on December 16, 2015, 08:41:25 PMQuote from: cl94 on December 14, 2015, 06:04:21 PMQuote from: UCFKnights on December 14, 2015, 05:52:09 PM
I've only seen 1 or 2 in my life but I really liked them, especially now with FYAs. It seems lilke an easy way to add quite a bit of traffic flow improvements. I see everyone here is claiming way too dangerous... I'd like to see some data on this. anyone have that available?
I'm going by how people drive on dual left turns in the midwest. I've seen too many accidents happen due to people leaving their lane while turning.
In the south suburbs of Chicago, the dotted line indicating where to turn is usually ignored. The drivers in the outer lane frequently tend to cross it, varying from just half a tire width to the entire car being inside the curve. They often don't allow the inner lane enough room and it often leads to the inner cars either hitting the median or causing the end of the turn to be extra sharp. I will not use the left/inner lane of a double left anymore because it has become that bad.
It extends east to at least Buffalo (which may as well be considered the Midwest). I see that every day. That or people on the inside take it too wide. Quite often, you'll have people on the inside making their turn so they end on the outside.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: 1995hoo on December 17, 2015, 02:29:18 PM
Post by: 1995hoo on December 17, 2015, 02:29:18 PM
Around here it's the people in the inside lane taking a wide turn. It's a huge problem when there's an optional right-turn lane because people in the far right lane don't even look as they cut left.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on December 17, 2015, 02:54:02 PM
Post by: jakeroot on December 17, 2015, 02:54:02 PM
I feel inclined to point out that not all of these double permissive turns always return to permissive mode. Sometimes, they are protected-only during the day, and permissive-only at night, when the traffic is so light (one or two cars at most per cycle), it's a waste to make the turn lanes protected-only. (In other words, the two lanes are only helpful during rush hour -- other times of the day, they're overkill, so the lights go permissive instead).
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: riiga on December 17, 2015, 07:25:45 PM
Post by: riiga on December 17, 2015, 07:25:45 PM
Quote from: jakeroot on December 17, 2015, 02:54:02 PMCouldn't you just keep them protected then? You get the safety benefit of proteced signals, and outside of rush hour lights here at least operate on demand with induction loops, I can count on my fingers the number of times I've had to wait at a red light because no one was coming.
I feel inclined to point out that not all of these double permissive turns always return to permissive mode. Sometimes, they are protected-only during the day, and permissive-only at night, when the traffic is so light (one or two cars at most per cycle), it's a waste to make the turn lanes protected-only. (In other words, the two lanes are only helpful during rush hour -- other times of the day, they're overkill, so the lights go permissive instead).
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: UCFKnights on December 17, 2015, 09:08:44 PM
Post by: UCFKnights on December 17, 2015, 09:08:44 PM
Quote from: riiga on December 17, 2015, 07:25:45 PMHaving to stop is still disruptive, bad for the environment, and increases wear on vehicles. In areas without permissive signals (whether because of dual left turn lanes or otherwise), I'm constantly stopped at night as one person pulls into the left turn lane while I'm travelling down at 55mph straight. And of course, when I do eventually want to turn, I have to stop even though there is very clearly no oncoming traffic. If its safe, why make people stop at all?Quote from: jakeroot on December 17, 2015, 02:54:02 PMCouldn't you just keep them protected then? You get the safety benefit of proteced signals, and outside of rush hour lights here at least operate on demand with induction loops, I can count on my fingers the number of times I've had to wait at a red light because no one was coming.
I feel inclined to point out that not all of these double permissive turns always return to permissive mode. Sometimes, they are protected-only during the day, and permissive-only at night, when the traffic is so light (one or two cars at most per cycle), it's a waste to make the turn lanes protected-only. (In other words, the two lanes are only helpful during rush hour -- other times of the day, they're overkill, so the lights go permissive instead).
I know living in Orlando, the most dangerous intersections are the ones with the protected lefts. Everyday, I see people running the red lights because they don't want to have to wait another 4 minutes to make their turn. The permissive signals eliminate that anxiety and fear as there is a chance they can make the turn sooner. I know thats my reaction... if its turning red, rush through the light, if its going permissive, I can wait as I can go in a gap in traffic and won't have to wait for every other phase of the cycle.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: mrsman on December 30, 2015, 06:57:25 AM
Post by: mrsman on December 30, 2015, 06:57:25 AM
How about a dual permissive left turn with no traffic light at all.
From Los Angeles:
https://www.google.com/maps/@34.0417063,-118.2398621,3a,75y,336.11h,75.71t/data=!3m6!1e1!3m4!1s8L44gMXtW1wcReBFp6CpHQ!2e0!7i13312!8i6656!6m1!1e1
Here on the outskirts of Downtown LA, traffic from Whittier Blvd crosses the LA River (well, not now as the bridge is being replaced) and continues onto 6th Street. At Central, 6th is one-way eastbound, so westbound traffic must turn right onto Central and then left onto 5th. 5th/Central is a T-intersection, with 5th being a one-way going away from the T. The main stream of traffic is northbound Central turning left onto 5th. Southbound Central has a stop sign, and they must yield to all the turning traffic.
I don't like this setup and would prefer a light at this intersection. The left turn could be the dominant phase, but it would be much safer if southbound Central had their own light.
From Los Angeles:
https://www.google.com/maps/@34.0417063,-118.2398621,3a,75y,336.11h,75.71t/data=!3m6!1e1!3m4!1s8L44gMXtW1wcReBFp6CpHQ!2e0!7i13312!8i6656!6m1!1e1
Here on the outskirts of Downtown LA, traffic from Whittier Blvd crosses the LA River (well, not now as the bridge is being replaced) and continues onto 6th Street. At Central, 6th is one-way eastbound, so westbound traffic must turn right onto Central and then left onto 5th. 5th/Central is a T-intersection, with 5th being a one-way going away from the T. The main stream of traffic is northbound Central turning left onto 5th. Southbound Central has a stop sign, and they must yield to all the turning traffic.
I don't like this setup and would prefer a light at this intersection. The left turn could be the dominant phase, but it would be much safer if southbound Central had their own light.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: roadfro on December 30, 2015, 07:53:44 AM
Post by: roadfro on December 30, 2015, 07:53:44 AM
^ That's more of a "free left" situation, since the left turn direction is not controlled and the opposing direction has a stop sign.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Brandon on December 30, 2015, 10:55:52 AM
Post by: Brandon on December 30, 2015, 10:55:52 AM
Not an uncommon situation where there are Michigan Lefts: https://goo.gl/maps/DmrwcjyWDXs
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on December 30, 2015, 03:30:40 PM
Post by: jakeroot on December 30, 2015, 03:30:40 PM
Quote from: Brandon on December 30, 2015, 10:55:52 AM
Not an uncommon situation where there are Michigan Lefts: https://goo.gl/maps/DmrwcjyWDXs
I don't think that's necessarily the same thing (although they are related).
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: cl94 on December 30, 2015, 04:02:56 PM
Post by: cl94 on December 30, 2015, 04:02:56 PM
Quote from: Brandon on December 30, 2015, 10:55:52 AM
Not an uncommon situation where there are Michigan Lefts: https://goo.gl/maps/DmrwcjyWDXs
Those are protected by default because there is no oncoming traffic and no pedestrians. Isn't the same.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: 74/171FAN on December 30, 2015, 04:46:33 PM
Post by: 74/171FAN on December 30, 2015, 04:46:33 PM
Here is one I found on NC 42 (https://www.google.com/maps/@35.6032691,-78.5708597,3a,75y,234.91h,72.61t/data=!3m6!1e1!3m4!1sPkg2jfI4Xj_Siem9vKlKCw!2e0!7i13312!8i6656) in Garner a few years back. This is at Cleveland Rd just west of I-40 (Exit 312).
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi622.photobucket.com%2Falbums%2Ftt304%2F24DIDNOTWIN%2FNC%252042%2520WB%2520at%2520SR%25201010Cleveland%2520Rd-Posted_zps2vivuwzy.png&hash=61939e48f93d5d3a0ecf37a38ff4ba7bf2ba568f)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi622.photobucket.com%2Falbums%2Ftt304%2F24DIDNOTWIN%2FNC%252042%2520WB%2520at%2520SR%25201010Cleveland%2520Rd-Posted_zps2vivuwzy.png&hash=61939e48f93d5d3a0ecf37a38ff4ba7bf2ba568f)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Jovet on December 30, 2015, 06:04:01 PM
Post by: Jovet on December 30, 2015, 06:04:01 PM
I have not seen one of these, but I echo the sentiments of others: protected left turns are complicated enough for many drivers... permissive tandem turn lanes are not a safe move. I'd motion for their banishment, if I were in charge of rulemaking.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Tom958 on December 31, 2015, 10:32:38 PM
Post by: Tom958 on December 31, 2015, 10:32:38 PM
Quote from: Tom958 on December 15, 2015, 06:59:04 AMThere's one near my house in Gwinnett County, GA (https://www.google.com/maps/@33.9553145,-84.0567781,3a,75y,42.57h,78.28t/data=!3m6!1e1!3m4!1sp2dOn2RfYlSyvAAlqPFRSg!2e0!7i13312!8i6656). It's an anomaly, AFAIK, but it's been like this for decades, even as FYA's have started to appear nearby. I hope it remains as is-- I've never had a problem with it. I guess that's mainly because straight-through traffic between Cruse Road and Marathon Blvd is very light.
They're replacing it with a protected phase. Oh, well, it was nice while it lasted. :no:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FEru4V6b.jpg%3F1&hash=c41d268ce0477a0cf5b2634a21fdb09b76fc1a7b)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Brandon on January 01, 2016, 08:52:32 AM
Post by: Brandon on January 01, 2016, 08:52:32 AM
Here's another one: https://goo.gl/maps/nwaCg11bp5H2
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: roadfro on January 01, 2016, 03:49:05 PM
Post by: roadfro on January 01, 2016, 03:49:05 PM
Quote from: Brandon on January 01, 2016, 08:52:32 AM
Here's another one: https://goo.gl/maps/nwaCg11bp5H2
Is that a permitted left though? Looks like it could be a split phase setup just using 5-aspect heads, due to the shared lane... In street view, it only shows as either red or green arrow+ball (with red for opposing traffic) in all time views, so this seems like a split phase.
If it is a permitted setup, that's rarely a good idea to have a protected/permitted left with a shared lane...that can hinder throughput.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: cl94 on January 01, 2016, 04:16:13 PM
Post by: cl94 on January 01, 2016, 04:16:13 PM
Quote from: roadfro on January 01, 2016, 03:49:05 PMQuote from: Brandon on January 01, 2016, 08:52:32 AM
Here's another one: https://goo.gl/maps/nwaCg11bp5H2
Is that a permitted left though? Looks like it could be a split phase setup just using 5-aspect heads, due to the shared lane... In street view, it only shows as either red or green arrow+ball (with red for opposing traffic) in all time views, so this seems like a split phase.
If it is a permitted setup, that's rarely a good idea to have a protected/permitted left with a shared lane...that can hinder throughput.
MUTCD actually prohibits using a shared left turn lane for a dual left if it isn't split phasing. Of course, you get places like the Adirondacks (https://www.google.com/maps/@43.3296972,-73.6849764,3a,22.4y,264.79h,84.06t/data=!3m6!1e1!3m4!1sMPd-l5CgBsMpr4iYbgaBNg!2e0!7i13312!8i6656) which violate this, but the installation posted in this thread may date to before the restriction was put in place.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Big John on January 01, 2016, 04:27:36 PM
Post by: Big John on January 01, 2016, 04:27:36 PM
^^ Another one in Green Bay: https://www.google.com/maps/@44.5249833,-88.0892947,3a,75y,7.03h,76.94t/data=!3m6!1e1!3m4!1sCbe9JUZaXVcWYd9jakNIrw!2e0!7i13312!8i6656 Worse is that if you want to go straight (though not many do), your only option is the middle shared lane where you may be stuck behind someone trying to make a left turn. There is a sign there saying left turn yield on green.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Brandon on January 01, 2016, 04:33:52 PM
Post by: Brandon on January 01, 2016, 04:33:52 PM
Quote from: roadfro on January 01, 2016, 03:49:05 PMQuote from: Brandon on January 01, 2016, 08:52:32 AM
Here's another one: https://goo.gl/maps/nwaCg11bp5H2
Is that a permitted left though? Looks like it could be a split phase setup just using 5-aspect heads, due to the shared lane... In street view, it only shows as either red or green arrow+ball (with red for opposing traffic) in all time views, so this seems like a split phase.
If it is a permitted setup, that's rarely a good idea to have a protected/permitted left with a shared lane...that can hinder throughput.
It's very much a permitted setup with a green for the other direction. I've been through it many, many times, but it's never all that busy.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: roadfro on January 01, 2016, 04:53:29 PM
Post by: roadfro on January 01, 2016, 04:53:29 PM
Quote from: Brandon on January 01, 2016, 04:33:52 PMQuote from: roadfro on January 01, 2016, 03:49:05 PMQuote from: Brandon on January 01, 2016, 08:52:32 AM
Here's another one: https://goo.gl/maps/nwaCg11bp5H2
Is that a permitted left though? Looks like it could be a split phase setup just using 5-aspect heads, due to the shared lane... In street view, it only shows as either red or green arrow+ball (with red for opposing traffic) in all time views, so this seems like a split phase.
If it is a permitted setup, that's rarely a good idea to have a protected/permitted left with a shared lane...that can hinder throughput.
It's very much a permitted setup with a green for the other direction. I've been through it many, many times, but it's never all that busy.
Does the signal ever display the green ball alone without the arrow? I didn't see evidence of this in Street View.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Brandon on January 01, 2016, 08:04:17 PM
Post by: Brandon on January 01, 2016, 08:04:17 PM
Quote from: roadfro on January 01, 2016, 04:53:29 PMQuote from: Brandon on January 01, 2016, 04:33:52 PMQuote from: roadfro on January 01, 2016, 03:49:05 PMQuote from: Brandon on January 01, 2016, 08:52:32 AM
Here's another one: https://goo.gl/maps/nwaCg11bp5H2
Is that a permitted left though? Looks like it could be a split phase setup just using 5-aspect heads, due to the shared lane... In street view, it only shows as either red or green arrow+ball (with red for opposing traffic) in all time views, so this seems like a split phase.
If it is a permitted setup, that's rarely a good idea to have a protected/permitted left with a shared lane...that can hinder throughput.
It's very much a permitted setup with a green for the other direction. I've been through it many, many times, but it's never all that busy.
Does the signal ever display the green ball alone without the arrow? I didn't see evidence of this in Street View.
Yes, it does. There's not usually a lot of traffic coming from the other direction, but it does have the green without the arrow.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: UCFKnights on January 02, 2016, 11:21:54 AM
Post by: UCFKnights on January 02, 2016, 11:21:54 AM
Quote from: cl94 on January 01, 2016, 04:16:13 PMHow is that meant to be interpreted (or enforced)? Is the center lane permissive left while the left is protected?Quote from: roadfro on January 01, 2016, 03:49:05 PMQuote from: Brandon on January 01, 2016, 08:52:32 AM
Here's another one: https://goo.gl/maps/nwaCg11bp5H2
Is that a permitted left though? Looks like it could be a split phase setup just using 5-aspect heads, due to the shared lane... In street view, it only shows as either red or green arrow+ball (with red for opposing traffic) in all time views, so this seems like a split phase.
If it is a permitted setup, that's rarely a good idea to have a protected/permitted left with a shared lane...that can hinder throughput.
MUTCD actually prohibits using a shared left turn lane for a dual left if it isn't split phasing. Of course, you get places like the Adirondacks (https://www.google.com/maps/@43.3296972,-73.6849764,3a,22.4y,264.79h,84.06t/data=!3m6!1e1!3m4!1sMPd-l5CgBsMpr4iYbgaBNg!2e0!7i13312!8i6656) which violate this, but the installation posted in this thread may date to before the restriction was put in place.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Brandon on January 02, 2016, 05:07:47 PM
Post by: Brandon on January 02, 2016, 05:07:47 PM
Quote from: UCFKnights on January 02, 2016, 11:21:54 AMQuote from: cl94 on January 01, 2016, 04:16:13 PMHow is that meant to be interpreted (or enforced)? Is the center lane permissive left while the left is protected?Quote from: roadfro on January 01, 2016, 03:49:05 PMQuote from: Brandon on January 01, 2016, 08:52:32 AM
Here's another one: https://goo.gl/maps/nwaCg11bp5H2
Is that a permitted left though? Looks like it could be a split phase setup just using 5-aspect heads, due to the shared lane... In street view, it only shows as either red or green arrow+ball (with red for opposing traffic) in all time views, so this seems like a split phase.
If it is a permitted setup, that's rarely a good idea to have a protected/permitted left with a shared lane...that can hinder throughput.
MUTCD actually prohibits using a shared left turn lane for a dual left if it isn't split phasing. Of course, you get places like the Adirondacks (https://www.google.com/maps/@43.3296972,-73.6849764,3a,22.4y,264.79h,84.06t/data=!3m6!1e1!3m4!1sMPd-l5CgBsMpr4iYbgaBNg!2e0!7i13312!8i6656) which violate this, but the installation posted in this thread may date to before the restriction was put in place.
Both of those lanes are permissive, and the signal dates to at least the 1970s like that.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jjakucyk on January 02, 2016, 09:37:14 PM
Post by: jjakucyk on January 02, 2016, 09:37:14 PM
How about something like this. Dual left turn lanes with no protected phase at all, just standard green balls, timer-actuated too, no detectors. https://goo.gl/maps/qbdNs3WEjQv This would date to the late 1960s when I-71 was built in downtown Cincinnati, and this overpass is way over-engineered at 6 lanes (probably for pre-interstate traffic that was all diverted). Plus Elsinore coming down the hill from the top right is pretty lightly trafficked so there's usually only one or two cars at a time coming from that direction anyway.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: JMAN_WiS&S on January 13, 2016, 10:40:47 PM
Post by: JMAN_WiS&S on January 13, 2016, 10:40:47 PM
https://www.google.com/maps/place/St+Croix+Trail,+Oak+Park+Heights,+MN+55082/@45.0355219,-92.7925001,3a,75y,142h,90t/data=!3m4!1e1!3m2!1swY5Tktp77WnFBZTL-Z5yjA!2e0!4m2!3m1!1s0x52b2ca0483785575:0xd9f7d99b33d1f516 (https://www.google.com/maps/place/St+Croix+Trail,+Oak+Park+Heights,+MN+55082/@45.0355219,-92.7925001,3a,75y,142h,90t/data=!3m4!1e1!3m2!1swY5Tktp77WnFBZTL-Z5yjA!2e0!4m2!3m1!1s0x52b2ca0483785575:0xd9f7d99b33d1f516)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on January 13, 2016, 11:03:33 PM
Post by: jakeroot on January 13, 2016, 11:03:33 PM
Quote from: JMAN12343610 on January 13, 2016, 10:40:47 PM
https://www.google.com/maps/place/St+Croix+Trail,+Oak+Park+Heights,+MN+55082/@45.0355219,-92.7925001,3a,75y,142h,90t/data=!3m4!1e1!3m2!1swY5Tktp77WnFBZTL-Z5yjA!2e0!4m2!3m1!1s0x52b2ca0483785575:0xd9f7d99b33d1f516 (https://www.google.com/maps/place/St+Croix+Trail,+Oak+Park+Heights,+MN+55082/@45.0355219,-92.7925001,3a,75y,142h,90t/data=!3m4!1e1!3m2!1swY5Tktp77WnFBZTL-Z5yjA!2e0!4m2!3m1!1s0x52b2ca0483785575:0xd9f7d99b33d1f516)
I think the dual permissive lefts work better with flashing yellow arrows. Not sure why. Glad Minnesota's DOT doesn't outright ban their use (engineering judgement permits any sort of signal combination -- :thumbsup:).
Quote from: jjakucyk on January 02, 2016, 09:37:14 PM
How about something like this. Dual left turn lanes with no protected phase at all, just standard green balls, timer-actuated too, no detectors. https://goo.gl/maps/qbdNs3WEjQv This would date to the late 1960s when I-71 was built in downtown Cincinnati, and this overpass is way over-engineered at 6 lanes (probably for pre-interstate traffic that was all diverted). Plus Elsinore coming down the hill from the top right is pretty lightly trafficked so there's usually only one or two cars at a time coming from that direction anyway.
Interesting that the road wasn't scaled back after the 71 freeway was finished. Pretty cool nonetheless. I think this might be unique in being the only dual permissive left that has no protected phase.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: tradephoric on January 14, 2016, 10:17:11 AM
Post by: tradephoric on January 14, 2016, 10:17:11 AM
Quote from: jakeroot on January 13, 2016, 11:03:33 PMQuote from: JMAN12343610 on January 13, 2016, 10:40:47 PM
https://www.google.com/maps/place/St+Croix+Trail,+Oak+Park+Heights,+MN+55082/@45.0355219,-92.7925001,3a,75y,142h,90t/data=!3m4!1e1!3m2!1swY5Tktp77WnFBZTL-Z5yjA!2e0!4m2!3m1!1s0x52b2ca0483785575:0xd9f7d99b33d1f516 (https://www.google.com/maps/place/St+Croix+Trail,+Oak+Park+Heights,+MN+55082/@45.0355219,-92.7925001,3a,75y,142h,90t/data=!3m4!1e1!3m2!1swY5Tktp77WnFBZTL-Z5yjA!2e0!4m2!3m1!1s0x52b2ca0483785575:0xd9f7d99b33d1f516)
I think the dual permissive lefts work better with flashing yellow arrows. Not sure why. Glad Minnesota's DOT doesn't outright ban their use (engineering judgement permits any sort of signal combination -- :thumbsup:).
Those left-turn signal heads should be bagged during construction.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jeffandnicole on January 14, 2016, 10:48:44 AM
Post by: jeffandnicole on January 14, 2016, 10:48:44 AM
Quote from: tradephoric on January 14, 2016, 10:17:11 AMQuote from: jakeroot on January 13, 2016, 11:03:33 PMQuote from: JMAN12343610 on January 13, 2016, 10:40:47 PM
https://www.google.com/maps/place/St+Croix+Trail,+Oak+Park+Heights,+MN+55082/@45.0355219,-92.7925001,3a,75y,142h,90t/data=!3m4!1e1!3m2!1swY5Tktp77WnFBZTL-Z5yjA!2e0!4m2!3m1!1s0x52b2ca0483785575:0xd9f7d99b33d1f516 (https://www.google.com/maps/place/St+Croix+Trail,+Oak+Park+Heights,+MN+55082/@45.0355219,-92.7925001,3a,75y,142h,90t/data=!3m4!1e1!3m2!1swY5Tktp77WnFBZTL-Z5yjA!2e0!4m2!3m1!1s0x52b2ca0483785575:0xd9f7d99b33d1f516)
I think the dual permissive lefts work better with flashing yellow arrows. Not sure why. Glad Minnesota's DOT doesn't outright ban their use (engineering judgement permits any sort of signal combination -- :thumbsup:).
Those left-turn signal heads should be bagged during construction.
If you look carefully, the individual lights have been gift-wrapped.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: tradephoric on January 14, 2016, 11:59:53 AM
Post by: tradephoric on January 14, 2016, 11:59:53 AM
^Good catch, i didn't notice that the individual lights were wrapped. I'm just use to seeing the entire signal head bagged. IMO, having the entire signal head bagged makes it more obvious to drivers that the signal head is not in use.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Mohkfry on January 14, 2016, 12:11:18 PM
Post by: Mohkfry on January 14, 2016, 12:11:18 PM
Quote from: jakeroot on January 13, 2016, 11:03:33 PMQuote from: JMAN12343610 on January 13, 2016, 10:40:47 PM
https://www.google.com/maps/place/St+Croix+Trail,+Oak+Park+Heights,+MN+55082/@45.0355219,-92.7925001,3a,75y,142h,90t/data=!3m4!1e1!3m2!1swY5Tktp77WnFBZTL-Z5yjA!2e0!4m2!3m1!1s0x52b2ca0483785575:0xd9f7d99b33d1f516 (https://www.google.com/maps/place/St+Croix+Trail,+Oak+Park+Heights,+MN+55082/@45.0355219,-92.7925001,3a,75y,142h,90t/data=!3m4!1e1!3m2!1swY5Tktp77WnFBZTL-Z5yjA!2e0!4m2!3m1!1s0x52b2ca0483785575:0xd9f7d99b33d1f516)
I think the dual permissive lefts work better with flashing yellow arrows. Not sure why. Glad Minnesota's DOT doesn't outright ban their use (engineering judgement permits any sort of signal combination -- :thumbsup:).Quote from: jjakucyk on January 02, 2016, 09:37:14 PM
How about something like this. Dual left turn lanes with no protected phase at all, just standard green balls, timer-actuated too, no detectors. https://goo.gl/maps/qbdNs3WEjQv This would date to the late 1960s when I-71 was built in downtown Cincinnati, and this overpass is way over-engineered at 6 lanes (probably for pre-interstate traffic that was all diverted). Plus Elsinore coming down the hill from the top right is pretty lightly trafficked so there's usually only one or two cars at a time coming from that direction anyway.
Interesting that the road wasn't scaled back after the 71 freeway was finished. Pretty cool nonetheless. I think this might be unique in being the only dual permissive left that has no protected phase.
Nope, here's another one not far from where I live.
https://www.google.com/maps/@41.5036083,-87.4714439,3a,75y,96.18h,75.06t/data=!3m6!1e1!3m4!1sBgz-MViN_o5JHW7SF88lsw!2e0!7i13312!8i6656!6m1!1e1
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jeffandnicole on January 14, 2016, 12:15:40 PM
Post by: jeffandnicole on January 14, 2016, 12:15:40 PM
Quote from: tradephoric on January 14, 2016, 11:59:53 AM
^Good catch, i didn't notice that the individual lights were wrapped. I'm just use to seeing the entire signal head bagged. IMO, having the entire signal head bagged makes it more obvious to drivers that the signal head is not in use.
Yeah, I had to zoom in pretty close to determine what happened. If you look real carefully, you can see the red light is lit underneath the bag.
Here's somewhat of a similar situation: https://goo.gl/maps/2UHbNjsBQND2 . Train lights look like they're in use. But when you look real close, you see bags are covering the lights. https://goo.gl/maps/cAgUzNKoMLM2 Oh...there's no tracks either! https://goo.gl/maps/qDEzsgMLnsF2
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: thenetwork on January 14, 2016, 03:29:27 PM
Post by: thenetwork on January 14, 2016, 03:29:27 PM
My first encounter with Dual Lefts was in Toledo, OH back in the 80s. They were all over the city (and still are), and most had protected left arrows.
Since Toledo has always been good in synch-ing their traffic signals -- even adjusting the cycles in morning and afternoon rush hours -- there would be no need for them to go to a FYA or Doghouse. IMHO.
Since Toledo has always been good in synch-ing their traffic signals -- even adjusting the cycles in morning and afternoon rush hours -- there would be no need for them to go to a FYA or Doghouse. IMHO.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on April 04, 2016, 06:53:59 PM
Post by: jakeroot on April 04, 2016, 06:53:59 PM
Slightly thread revival warning:
Tucson is known for their dual permissive turns, as noted previously. They've even gone so far as to install 5-section heads for one of their "SPUIs", though there's a catch: it's not completely finished. The flyover has not been installed, nor has the road been completed beyond the "service road".
Anyone know of any other permissive SPUIs, regardless of the number of turn lanes?
The road with the dual turn is Broadway Blvd, and the road with the future flyover is AZ-210. Here's a couple of images:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FkzaFux6.png&hash=875c150b172da330a28f59a5a94f8b6bb9e36425)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fcmpnv74.png&hash=dbd7450abdb334ea1063d18f320b77e0819ca390)
Tucson is known for their dual permissive turns, as noted previously. They've even gone so far as to install 5-section heads for one of their "SPUIs", though there's a catch: it's not completely finished. The flyover has not been installed, nor has the road been completed beyond the "service road".
Anyone know of any other permissive SPUIs, regardless of the number of turn lanes?
The road with the dual turn is Broadway Blvd, and the road with the future flyover is AZ-210. Here's a couple of images:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FkzaFux6.png&hash=875c150b172da330a28f59a5a94f8b6bb9e36425)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fcmpnv74.png&hash=dbd7450abdb334ea1063d18f320b77e0819ca390)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: cl94 on April 04, 2016, 07:12:28 PM
Post by: cl94 on April 04, 2016, 07:12:28 PM
Quote from: jakeroot on April 04, 2016, 06:53:59 PM
Anyone know of any other permissive SPUIs, regardless of the number of turn lanes?
Nope. The baby half-SPUI at the VT 9/279 intersection is protected, as is every SPUI in New York and every one I know of in Ohio.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: lordsutch on April 04, 2016, 07:48:43 PM
Post by: lordsutch on April 04, 2016, 07:48:43 PM
Quote from: jakeroot on April 04, 2016, 06:53:59 PM
Anyone know of any other permissive SPUIs, regardless of the number of turn lanes?
Southbound Kirby Rd to TN 385 eastbound in Memphis used to have a permissive doghouse signal for a while (a year or two) after it went on a diet from two left turn lanes to one, but it's now back to a protected-only signal. As far as I know, that's the only permissive signal ever installed at one of 385's SPUIs.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Revive 755 on April 04, 2016, 08:18:22 PM
Post by: Revive 755 on April 04, 2016, 08:18:22 PM
Quote from: Brandon on January 01, 2016, 08:52:32 AM
Here's another one: https://goo.gl/maps/nwaCg11bp5H2
There's slightly more of the permissive dual lefts in Chicagoland than triple lefts. There's also:
* Thorndale Avenue at Park Avenue in Itasca (until IL 390 is finished), with permissive dual lefts for both eastbound and southbound: Streetview (https://www.google.com/maps/@41.983587,-88.012649,3a,75y,48.72h,83.24t/data=!3m6!1e1!3m4!1se3kb1mlubxpoqlPnZfA2pg!2e0!7i13312!8i6656?hl=en) (DuPage County's jurisdiction)
* Sunset Ridge Road at Skokie Boulevard in Northbrook (IIRC under Cook County's jurisdiction) Streetview (https://www.google.com/maps/@42.1345179,-87.7897059,3a,75y,68.43h,76.69t/data=!3m6!1e1!3m4!1sL2Jx2eiEIiEJ-JQWs37JLQ!2e0!7i13312!8i6656?hl=en)
I think there is one more in Chicagoland that I can't place as of this typing.
As for single point interchanges with permissive left turns:
* Grand Avenue at the Amstutz Expressway/IL 137 in Waukegan (probably doesn't count since the ramps are controlled by stop signs) Streetview (https://www.google.com/maps/@42.3638835,-87.8285108,3a,75y,230.63h,82.68t/data=!3m7!1e1!3m5!1sTT3_EDjHZD-nLaCDQEkCWA!2e0!6s%2F%2Fgeo3.ggpht.com%2Fcbk%3Fpanoid%3DTT3_EDjHZD-nLaCDQEkCWA%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D41.986012%26pitch%3D0!7i13312!8i6656?hl=en)
* Nebraska Highway 2 at US 77 in Lincoln (Streetview (https://www.google.com/maps/@40.7876137,-96.7298594,3a,81.4y,252.68h,87.86t/data=!3m7!1e1!3m5!1sBUn-HM1JOzV-sZd6r5xBcA!2e0!6s%2F%2Fgeo3.ggpht.com%2Fcbk%3Fpanoid%3DBUn-HM1JOzV-sZd6r5xBcA%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D237.67863%26pitch%3D0!7i3328!8i1664?hl=en))
As for the poll in this thread: Yes, I think permissive dual lefts should be allowable, especially when they are across an opposing through movement with a low volume. Missouri has it in their manual that with engineering judgement, a dual left across a single opposing through can be used (see about halfway down the page here). (http://epg.modot.org/index.php?title=902.5_Traffic_Control_Signal_Features_%28MUTCD_Chapter_4D%29)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on April 04, 2016, 10:06:37 PM
Post by: jakeroot on April 04, 2016, 10:06:37 PM
Quote from: Revive 755 on April 04, 2016, 08:18:22 PM
As for single point interchanges with permissive left turns:
* Grand Avenue at the Amstutz Expressway/IL 137 in Waukegan (probably doesn't count since the ramps are controlled by stop signs) Streetview (https://www.google.com/maps/@42.3638835,-87.8285108,3a,75y,230.63h,82.68t/data=!3m7!1e1!3m5!1sTT3_EDjHZD-nLaCDQEkCWA!2e0!6s%2F%2Fgeo3.ggpht.com%2Fcbk%3Fpanoid%3DTT3_EDjHZD-nLaCDQEkCWA%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D41.986012%26pitch%3D0!7i13312!8i6656?hl=en)
* Nebraska Highway 2 at US 77 in Lincoln (Streetview (https://www.google.com/maps/@40.7876137,-96.7298594,3a,81.4y,252.68h,87.86t/data=!3m7!1e1!3m5!1sBUn-HM1JOzV-sZd6r5xBcA!2e0!6s%2F%2Fgeo3.ggpht.com%2Fcbk%3Fpanoid%3DBUn-HM1JOzV-sZd6r5xBcA%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D237.67863%26pitch%3D0!7i3328!8i1664?hl=en))
I almost wrote a sentence about excluding the Amstutz stop signs, but I figured I'd wait to see if anyone would bring them up. Didn't think it would be reply #2!
There's another permissive SPUI in Billings, Montana. Mullowney Lane at I-90 (streetview (https://goo.gl/CFlA7J)):
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FyHQ0zIX.png&hash=9cf76e951b2b837ec366b3b33668942fd4eb0cc6)
Slightly related: can anyone think of any reason why nearly all single-lane SPUIs are protected? Sometimes permissive turns are disallowed because of overlap, but SPUIs are designed to run with opposing left turns. If anything, they're built for permissive signals! I get why the majority are protected-only (most are dual turns, which are almost always protected), but the single-lane SPUIs would be great candidates for permissive signals.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Jet380 on April 08, 2016, 12:33:46 AM
Post by: Jet380 on April 08, 2016, 12:33:46 AM
Quote from: Revive 755 on April 04, 2016, 08:18:22 PM
Slightly related: can anyone think of any reason why nearly all single-lane SPUIs are protected? Sometimes permissive turns are disallowed because of overlap, but SPUIs are designed to run with opposing left turns. If anything, they're built for permissive signals! I get why the majority are protected-only (most are dual turns, which are almost always protected), but the single-lane SPUIs would be great candidates for permissive signals.
My guess would be the intersection geometry, SPUIs tend to be on the larger side and have very wide sweeping left turns. This would make it take longer for turning vehicles to clear the opposing lanes and reduce the acceptable gap to the point where it could be too difficult to judge. I'd also imagine that SPUIs are normally built at busy locations with high enough turning movements to justify fully-protected phasing.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on April 09, 2016, 02:53:45 AM
Post by: jakeroot on April 09, 2016, 02:53:45 AM
I did manage to find some dual permissive right turns outside of North America. Here's one a couple from South Africa:
Bryanston Drive @ William Nicole Drive (https://goo.gl/9gaNOH), Sandton, Gauteng:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fd5zGxGY.png&hash=ef4939c1683f4324276703967681379eee1fd654)
There are actually several in a row:
Sloane St @ William Nicole Drive (https://goo.gl/xv7UIM), Sandton, Gauteng:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F3Zf7YOj.png&hash=6dc551e88c4fb1038610812583693cb1862b0d7b)
EDIT 2: Looks like South Africa actually has quite a few dual permissive turns. In fact, for quieter intersections, it appears to be the normal phasing style.
EDIT 3: No bullshit, triple permissive turn. Damn South Africa...
Sandton Drive @ the M81 (https://goo.gl/T8h1GS), Sandton, Gauteng:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FYNFuGdL.png&hash=16d3be83364c9a80d85621437383268991ce9d3b)
EDIT 4: As you might have expected at this rate ... quadruple permissive right turn...
Republic Rd @ the M81 (https://goo.gl/kyx9dP), Sandton, Gauteng:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F1hUNetF.png&hash=000e9ad56112f2fb62d1f0d491dad3cd1e3e63c5)
Many of these appear to be split-phased, but if you click around, you can almost always find the permissive phase.
Bryanston Drive @ William Nicole Drive (https://goo.gl/9gaNOH), Sandton, Gauteng:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fd5zGxGY.png&hash=ef4939c1683f4324276703967681379eee1fd654)
There are actually several in a row:
Sloane St @ William Nicole Drive (https://goo.gl/xv7UIM), Sandton, Gauteng:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F3Zf7YOj.png&hash=6dc551e88c4fb1038610812583693cb1862b0d7b)
EDIT 2: Looks like South Africa actually has quite a few dual permissive turns. In fact, for quieter intersections, it appears to be the normal phasing style.
EDIT 3: No bullshit, triple permissive turn. Damn South Africa...
Sandton Drive @ the M81 (https://goo.gl/T8h1GS), Sandton, Gauteng:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FYNFuGdL.png&hash=16d3be83364c9a80d85621437383268991ce9d3b)
EDIT 4: As you might have expected at this rate ... quadruple permissive right turn...
Republic Rd @ the M81 (https://goo.gl/kyx9dP), Sandton, Gauteng:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F1hUNetF.png&hash=000e9ad56112f2fb62d1f0d491dad3cd1e3e63c5)
Many of these appear to be split-phased, but if you click around, you can almost always find the permissive phase.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: swbrotha100 on April 12, 2016, 09:13:43 AM
Post by: swbrotha100 on April 12, 2016, 09:13:43 AM
I think dual permissive left turns should be rare, and not common like it is in places like Tucson. If they're going to be used, at least use FYA signals for them. At least one intersection in Chandler AZ has this setup with the FYAs (Alma School Rd and Ray Rd).
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: mrsman on April 12, 2016, 08:21:28 PM
Post by: mrsman on April 12, 2016, 08:21:28 PM
Quote from: jakeroot on April 09, 2016, 02:53:45 AM
Many of these appear to be split-phased, but if you click around, you can almost always find the permissive phase.
Split-phased should not count as permissive, because those are always protected. It just happens to be that the protected left turn phase is equal to the straight-through traffic phase.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on April 12, 2016, 10:49:11 PM
Post by: jakeroot on April 12, 2016, 10:49:11 PM
Quote from: mrsman on April 12, 2016, 08:21:28 PMQuote from: jakeroot on April 09, 2016, 02:53:45 AM
Many of these appear to be split-phased, but if you click around, you can almost always find the permissive phase.
Split-phased should not count as permissive, because those are always protected. It just happens to be that the protected left turn phase is equal to the straight-through traffic phase.
Well of course they aren't permissive. I was trying to say that the signals, in several of the street view images, appear to be split phased, but when you click around, you can see that they are not. Several of South Africa's multi-lane permissive right turns have the second or third right turn lane as an option lane, so you'd think they'd be split phased.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Jardine on April 13, 2016, 10:51:55 AM
Post by: Jardine on April 13, 2016, 10:51:55 AM
Even with an obvious artillery cannon blowing up cars to deter folks attempting lane changing while dual left turning, and/or the folks dual left turning onto streets with more than 2 lanes and randomly going down whatever lane they want regardless of whether or not anyone is beside them on either side and they are also attempting a similar and non-compatible random lane selection themselves (all the while mowing down pedestrians) I'd say this is an extremely poor idea for places like Sarpy County Nebraska and Rockford Illinois.
And note, as we inch closer to the society envisioned in the film Idiocracy, this is going to get worse.
And note, as we inch closer to the society envisioned in the film Idiocracy, this is going to get worse.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on April 13, 2016, 02:36:51 PM
Post by: jakeroot on April 13, 2016, 02:36:51 PM
Quote from: Jardine on April 13, 2016, 10:51:55 AM
Even with an obvious artillery cannon blowing up cars to deter folks attempting lane changing while dual left turning, and/or the folks dual left turning onto streets with more than 2 lanes and randomly going down whatever lane they want regardless of whether or not anyone is beside them on either side and they are also attempting a similar and non-compatible random lane selection themselves (all the while mowing down pedestrians) I'd say this is an extremely poor idea for places like Sarpy County Nebraska and Rockford Illinois.
This perceived danger (vehicles changing lanes during a turn) seems to be the biggest fear among those who oppose dual permissive turns. My thought is this: are vehicles changing lanes during the permissive phase more often than during the protected phase?
Visibility really should be the argument against dual permissive turns. From studying the various dual turn lanes around the world, I've come up with two solutions to this issue:
1) Offset the dual turn lanes whenever possible. This requires slightly more ROW, but the cities that use this style seem to report fewer issues. Tucson is the best example. Note the chevrons between the left turn lanes and the through lanes. The FHWA's "Signalized Intersections: Informational Guide (https://goo.gl/31JHVM)" has a couple pages dedicated to Tucson's offset dual turns lanes, and notes a "potential issue is sight distance for the left-turning vehicles", and that "[t]he City of Tucson addresses this concern by offsetting the far lane by 1.2 to 1.5 m (4 to 5 ft) so that it has the same sight distance as a single left-turn lane" (PDF pg 338).
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FCajNWg0.png&hash=d5c73070660017d39535b614371332857809aefa)
2) Use secondary stop lines. These are almost unheard of in the US. They seem to be used more often in Europe, but more important to this conversation, South Africa has several dual permissive turn lanes with these secondary stop lines. In cities with drivers who pull pretty far forward into the intersection (cool with a single turn lane, but a little annoying with two turn lanes), this helps prevent the inside lane from being totally blind. As well, cities with more hesitant drivers will be more apt to pull forward to wait to turn, which helps with throughput. Because this secondary stop line is more of a "yield line", I'd recommend using sharks teeth, instead of the broken white lines used in South Africa:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FxRWAhR3.png&hash=0d34127525497676ed9f0e1f7f4eb40f4537d635)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F0Ce1Pwk.png&hash=634670ce4aade738b0de9b4ebbc0688e141ebcca)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: swbrotha100 on April 13, 2016, 04:33:30 PM
Post by: swbrotha100 on April 13, 2016, 04:33:30 PM
I personally think the permissive dual left turns should be a rarity instead of the norm in places like Tucson. I think one thing people who have never been to Tucson should realize that most of the Tucson/Pima County area uses lagging left turns at their signalized intersections.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: tradephoric on April 13, 2016, 04:44:28 PM
Post by: tradephoric on April 13, 2016, 04:44:28 PM
Quote from: swbrotha100 on April 13, 2016, 04:33:30 PM
I personally think the permissive dual left turns should be a rarity instead of the norm in places like Tucson. I think one thing people who have never been to Tucson should realize that most of the Tucson/Pima County area uses lagging left turns at their signalized intersections.
That's a great point. With lagging left turns drivers have an opportunity to clear the intersection at the end of the thru phase. Permissive dual left turns are somewhat more acceptable if drivers are guaranteed a protected left at the end of the thru phase.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on April 13, 2016, 05:12:54 PM
Post by: jakeroot on April 13, 2016, 05:12:54 PM
Quote from: swbrotha100 on April 13, 2016, 04:33:30 PM
I personally think the permissive dual left turns should be a rarity instead of the norm in places like Tucson.
But why? Is there any evidence to suggest that Tucson needs to do away with their permissive dual left turns? Tucson's website (https://goo.gl/cNbCb3) is highly protective of the permissive phase:
Quote
Protected Left Turn Arrows
Protected left turn signals include a red arrow along with the normal green and amber arrow. They allow left turning drivers to proceed only on the green arrow. This turning method is very inefficient and generally not used in Tucson. Adding inefficiencies to signal timing reduces overall capacity and increases congestion. With increased congestion comes the potential for an increase in certain types of accidents.
Permitted/Protected Left Turn Arrows
This is the most common turning method used in Tucson at locations having left turn arrows. During the permitted "green ball" part of the cycle, vehicles are allowed to turn when there are adequate gaps in opposing traffic. This type of left turn phasing is designed to help minimize delay by eliminating the need for the red arrow and allowing vehicles to turn on the green ball after opposing traffic has cleared. By not having the red arrow, motorists do not have to sit and wait to turn left even when there is no opposing traffic, a situation that often occurs during periods of low traffic volumes. The signal still provides a green left turn arrow for those not able to turn during the permitted phase.
Quote from: swbrotha100 on April 13, 2016, 04:33:30 PM
I think one thing people who have never been to Tucson should realize that most of the Tucson/Pima County area uses lagging left turns at their signalized intersections.
On leading vs lagging signals, with the advent of flashing yellow arrows, protected/permissive left turns should begin with the permissive phase. If there's only one car, they'll get through either in the middle of the cycle, or at the end. And if several more cars show up to turn left, the lagging protected left turn will be able to get the rest of them through the intersection, rather than making them wait for the next leading left turn, which would be after the cross-traffic gets their phase.
My point being, Tucson is pretty ingenious, having adopted lagging pro/per signals. Though I'd like to see them transition over to FYAs, so there isn't a red phase in the middle of the left turns.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: cl94 on April 13, 2016, 06:04:09 PM
Post by: cl94 on April 13, 2016, 06:04:09 PM
I think PPLT situations should always have the permissive phase at the end. Cuts down on cycle time, as traffic conditions might not warrant a permissive phase for the vehicles waiting to turn. It is not very common in much of the northeast, but NYSDOT Region 1 uses lagging phases extensively, especially if only one direction gets a protected phase. I do not know if the region's FYA intersections are leading or lagging.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: swbrotha100 on April 13, 2016, 06:59:47 PM
Post by: swbrotha100 on April 13, 2016, 06:59:47 PM
I lived in Tucson for years. Still visit once in awhile. I have seen the PPLT in practice. Maybe it would be different if Tucson used the flashing yellow left signals more. AFAIK the only flashing yellow left arrows in use are on Grant Rd on either side of Oracle Rd as part of the indirect left turn setup there. I believe Tucson insists on permissive dual left signals because most of them are lagging left turn, and because of the lack of freeways/highways, most of the arterials have to pick up the slack in terms of moving traffic around the city.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: UCFKnights on April 13, 2016, 09:39:25 PM
Post by: UCFKnights on April 13, 2016, 09:39:25 PM
Quote from: jakeroot on April 13, 2016, 05:12:54 PMI find that often if both directions get lagging lefts, there frequently is one car on one side and a whole group on the other, and the side with one car is forced to wait with a green arrow while all the opposing left turns happen, wasting time. I prefer when they do the direction with more left turn traffic leading, and the direction with less traffic lagging.Quote from: swbrotha100 on April 13, 2016, 04:33:30 PM
I personally think the permissive dual left turns should be a rarity instead of the norm in places like Tucson.
But why? Is there any evidence to suggest that Tucson needs to do away with their permissive dual left turns? Tucson's website (https://goo.gl/cNbCb3) is highly protective of the permissive phase:Quote
Protected Left Turn Arrows
Protected left turn signals include a red arrow along with the normal green and amber arrow. They allow left turning drivers to proceed only on the green arrow. This turning method is very inefficient and generally not used in Tucson. Adding inefficiencies to signal timing reduces overall capacity and increases congestion. With increased congestion comes the potential for an increase in certain types of accidents.
Permitted/Protected Left Turn Arrows
This is the most common turning method used in Tucson at locations having left turn arrows. During the permitted "green ball" part of the cycle, vehicles are allowed to turn when there are adequate gaps in opposing traffic. This type of left turn phasing is designed to help minimize delay by eliminating the need for the red arrow and allowing vehicles to turn on the green ball after opposing traffic has cleared. By not having the red arrow, motorists do not have to sit and wait to turn left even when there is no opposing traffic, a situation that often occurs during periods of low traffic volumes. The signal still provides a green left turn arrow for those not able to turn during the permitted phase.Quote from: swbrotha100 on April 13, 2016, 04:33:30 PM
I think one thing people who have never been to Tucson should realize that most of the Tucson/Pima County area uses lagging left turns at their signalized intersections.
On leading vs lagging signals, with the advent of flashing yellow arrows, protected/permissive left turns should begin with the permissive phase. If there's only one car, they'll get through either in the middle of the cycle, or at the end. And if several more cars show up to turn left, the lagging protected left turn will be able to get the rest of them through the intersection, rather than making them wait for the next leading left turn, which would be after the cross-traffic gets their phase.
My point being, Tucson is pretty ingenious, having adopted lagging pro/per signals. Though I'd like to see them transition over to FYAs, so there isn't a red phase in the middle of the left turns.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: tradephoric on April 14, 2016, 03:20:34 PM
Post by: tradephoric on April 14, 2016, 03:20:34 PM
A lot of agencies don't like lagging lefts at permissive signals because they can lead to a perceived yellow trap. The only way to prevent the perceived yellow trap is to tie the left-turns together (so that the left turns come on and terminate together). While this may be safer, it is quite inefficient if you have uneven left-turn queues. Here's an example of a perceived yellow trap at 38 seconds in the video (when a left turning driver sees the thru signal they are facing turn yellow, they mistakenly believe the opposing thru is turning yellow too).
https://www.youtube.com/watch?v=iW4xx11CLD0
https://www.youtube.com/watch?v=iW4xx11CLD0
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: cl94 on April 14, 2016, 03:36:09 PM
Post by: cl94 on April 14, 2016, 03:36:09 PM
I agree completely. Of course, the yellow trap is less of an issue if FYAs are used. NYSDOT Region 1 often staggers protected turn phases, having one direction leading and the other lagging. This eliminates the issue with uneven queues, but it can cause confusion.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: tradephoric on April 14, 2016, 05:42:14 PM
Post by: tradephoric on April 14, 2016, 05:42:14 PM
The FYA has pretty much solved the "yellow trap" problem but it doesn't prevent the perceived yellow trap. The staggered signal phasing of NYSDOT Region 1 still leads to a perceived yellow trap (assuming the left turns are PPLTs and not protected only). It comes down to some agencies are fine with perceived yellow traps and some never want to see it.
Here's a snippet from a webinar by the Oregon Transportation Research and Education Consortium about whether or not the FYA solves the yellow trap:
Here's a snippet from a webinar by the Oregon Transportation Research and Education Consortium about whether or not the FYA solves the yellow trap:
QuoteQ: What degree does the FYA solve the "yellow trap" problem. And does Washington County lead the protected interval at FYA or lead/lag to benefit coordination?
A: The FYA completely solves the yellow trap problem, because now the left turn lane has its own display. There is still the potential of the "perceived yellow trap" which is when the driver in the left lane sees the adjacent through go solid yellow and thinks that the FYA is also ending. It is called perceived, because the driver should focus on their own lane's signal control. Washington County prefers to lead the protected interval at FYA so if the protected left isn't needed then it can be skipped. In a coordinated system we will lead or lag whichever benefits the coordination. (SS)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on April 14, 2016, 06:49:53 PM
Post by: jakeroot on April 14, 2016, 06:49:53 PM
I don't know if the perceived yellow trap is really so much of an issue that lead/lag phasing should be discouraged. But, using more than one left turn FYA may help in making sure drivers understand which signals are for which movement. Oregon, and Washington, are notorious for using the bare minimum number of signals, with supplementary signals used only when required by sight-distance issues. Both of these states could benefit from additional supplementary signals, both for the through movements, and the turn movements.
The gold standard, as far as I'm concerned, is British Columbia, which requires three left turn heads for protected left turn movements. This kind of setup, with plenty of additional signals to bounce of off, should keep drivers focused on their signals, and not the through signals. I get the feeling that this style of setup, used with flashing yellow arrows, would prove far more successful than the typical OR/WA setup (or any other state that uses too few signals).
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FlOFEhGZ.png&hash=f2e97787b49e563e7cb267ad2e4d605a392f7a36)
The gold standard, as far as I'm concerned, is British Columbia, which requires three left turn heads for protected left turn movements. This kind of setup, with plenty of additional signals to bounce of off, should keep drivers focused on their signals, and not the through signals. I get the feeling that this style of setup, used with flashing yellow arrows, would prove far more successful than the typical OR/WA setup (or any other state that uses too few signals).
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FlOFEhGZ.png&hash=f2e97787b49e563e7cb267ad2e4d605a392f7a36)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: cl94 on April 14, 2016, 07:42:11 PM
Post by: cl94 on April 14, 2016, 07:42:11 PM
Quote from: tradephoric on April 14, 2016, 05:42:14 PM
The FYA has pretty much solved the "yellow trap" problem but it doesn't prevent the perceived yellow trap. The staggered signal phasing of NYSDOT Region 1 still leads to a perceived yellow trap (assuming the left turns are PPLTs and not protected only). It comes down to some agencies are fine with perceived yellow traps and some never want to see it.
Here's a snippet from a webinar by the Oregon Transportation Research and Education Consortium about whether or not the FYA solves the yellow trap:QuoteQ: What degree does the FYA solve the "yellow trap" problem. And does Washington County lead the protected interval at FYA or lead/lag to benefit coordination?
A: The FYA completely solves the yellow trap problem, because now the left turn lane has its own display. There is still the potential of the "perceived yellow trap" which is when the driver in the left lane sees the adjacent through go solid yellow and thinks that the FYA is also ending. It is called perceived, because the driver should focus on their own lane's signal control. Washington County prefers to lead the protected interval at FYA so if the protected left isn't needed then it can be skipped. In a coordinated system we will lead or lag whichever benefits the coordination. (SS)
R1 only uses the staggered phasing if it's fully-protected. PPLT gets leading if both directions, either lagging or leading if one direction.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: paulthemapguy on April 14, 2016, 11:27:30 PM
Post by: paulthemapguy on April 14, 2016, 11:27:30 PM
There's also the assumption that protected-permitted left turns will see drivers poking their nose into the intersection before turning left, yes? If we're dealing with a signal that isn't a lagging left (which is almost always the case), those lingering left-turners are going to book it out of the intersection when the signal changes to a yellow ball and a red ball. I'm not terribly confident that, in situations with dual left turn lanes, those two drivers are going to jet out of the intersection in an orderly and safe fashion. Just my 2 cents.
Quote from: jakerootThe gold standard, as far as I'm concerned, is British Columbia, which requires three left turn heads for protected left turn movements...And yet the left turn signals still have red balls instead of red arrows :-D I might be the only one who gets bothered by that, though (you see it everywhere too)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on April 14, 2016, 11:38:27 PM
Post by: jakeroot on April 14, 2016, 11:38:27 PM
Quote from: paulthemapguy on April 14, 2016, 11:27:30 PMQuote from: jakeroot on April 14, 2016, 06:49:53 PM
The gold standard, as far as I'm concerned, is British Columbia, which requires three left turn heads for protected left turn movements...
And yet the left turn signals still have red balls instead of red arrows :-D I might be the only one who gets bothered by that, though (you see it everywhere too)
That's a Canada thing. I can't honestly say I've ever seen a red arrow in BC before. Can't speak for the rest of the provinces, though I don't recall seeing any in Alberta last I was there.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: mariethefoxy on April 15, 2016, 01:24:42 AM
Post by: mariethefoxy on April 15, 2016, 01:24:42 AM
there is one I know of, its in Syosset NY on S Oyster Bay Road and the I-495 (LIE) Westbound Service Road.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on July 15, 2016, 03:20:14 PM
Post by: jakeroot on July 15, 2016, 03:20:14 PM
Quote from: cl94 on April 13, 2016, 06:04:09 PM
I think PPLT situations should always have the permissive phase at the end. Cuts down on cycle time, as traffic conditions might not warrant a permissive phase for the vehicles waiting to turn. It is not very common in much of the northeast, but NYSDOT Region 1 uses lagging phases extensively, especially if only one direction gets a protected phase. I do not know if the region's FYA intersections are leading or lagging.
Sorry to bring up such an old quote, but I need some clarification. When you said "permissive" in the first two sentences, did you mean "protected"? It makes more sense with the word "protected", especially since you brought up Region 1's lagging phasing immediately after:
Quote
I think PPLT situations should always have the *protected* phase at the end. Cuts down on cycle time, as traffic conditions might not warrant a *protected* phase for the vehicles waiting to turn...
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Brandon on July 15, 2016, 04:15:41 PM
Post by: Brandon on July 15, 2016, 04:15:41 PM
Quote from: jakeroot on April 14, 2016, 06:49:53 PM
The gold standard, as far as I'm concerned, is British Columbia, which requires three left turn heads for protected left turn movements.
Not unlike Illinois which requires two (minimum) signals per turning direction and three (minimum) for through traffic.
An example with permitted lefts (IDOT District 3): https://goo.gl/maps/5qq6x6dJKjo
An example with protected only lefts (IDOT District 1): https://goo.gl/maps/kXSRrhtd5iL2
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on July 15, 2016, 05:48:55 PM
Post by: jakeroot on July 15, 2016, 05:48:55 PM
Quote from: Brandon on July 15, 2016, 04:15:41 PMQuote from: jakeroot on April 14, 2016, 06:49:53 PM
The gold standard, as far as I'm concerned, is British Columbia, which requires three left turn heads for protected left turn movements.
Not unlike Illinois which requires two (minimum) signals per turning direction and three (minimum) for through traffic.
I've noticed that Illinois uses a lot of overhead stop-line signals (when five-section signals are involved). Can't say I'm a huge fan of this practice (I prefer post-mounted stop line signals, which I think are more common in Illinois anyways), but at least there's more than one signal, unlike out here in Washington and Oregon, where you're lucky to have more than one signal for turning movements (hence my preference for the BC standard).
From my experience, these places have the best signals:
- British Columbia (+1 for three pole-mounted protected left turns)
- California (-1 for their propensity to use protected lefts, but +1 for near-side pole mounted signals for through movements)
- Tucson, AZ (+1 for dual permissive lefts and near-side pole-mounted signals)
- Illinois (-1 when near-side overhead signals are used)
- Wisconsin (+1 for near-side pole mounted signals at nearly every junction)
- Colorado (+1 for overhead signals using backplates but not side-mounted signals -- I think this looks better and makes the mast-arms less bulky).
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: roadfro on July 16, 2016, 12:35:02 PM
Post by: roadfro on July 16, 2016, 12:35:02 PM
OT reply...
Terms might be a bit jumbled here... The "mast arm" is the part of the traffic signal assembly that sticks out over the roadway (typically horizontally, but can also be curved as seen in California). The "mast" is the vertical pole to which the mast arm (and side-mounted signals, if present) are attached. So a side-mounted signal head missing a backplate wouldn't affect the look of a mast arm.
Quote from: jakeroot on July 15, 2016, 05:48:55 PM
- Colorado (+1 for overhead signals using backplates but not side-mounted signals -- I think this looks better and makes the mast-arms less bulky).
Terms might be a bit jumbled here... The "mast arm" is the part of the traffic signal assembly that sticks out over the roadway (typically horizontally, but can also be curved as seen in California). The "mast" is the vertical pole to which the mast arm (and side-mounted signals, if present) are attached. So a side-mounted signal head missing a backplate wouldn't affect the look of a mast arm.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: coatimundi on July 16, 2016, 01:18:27 PM
Post by: coatimundi on July 16, 2016, 01:18:27 PM
It seems to have changed based on my more recent visits, but it used to be that, within the City of Tucson, a dual lane left turn could be taken on the solid green, yielding to oncoming traffic while, outside the city limits in unincorporated Pima County, while a single lane left could be taken on a solid green, a double was only on the arrow. I never really noticed it, but the local daily has a roads column, and it once published a question about it, with a county traffic engineer indicating that it was actually a rule.
Always thought that was weird.
Always thought that was weird.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: 7/8 on July 16, 2016, 01:32:07 PM
Post by: 7/8 on July 16, 2016, 01:32:07 PM
I believe these aren't allowed in Ontario. The way we currently signal dual left turns doesn't allow for this to even exist, since we don't use the FYA. Once the protected turn is over, the dual left turn lanes always face a red light (see interchange below).
https://www.google.ca/maps/@43.4284371,-80.4322768,3a,30y,40.12h,95.56t/data=!3m6!1e1!3m4!1sbHdd-94cz3CK0fKRHOfXEg!2e0!7i13312!8i6656 (https://www.google.ca/maps/@43.4284371,-80.4322768,3a,30y,40.12h,95.56t/data=!3m6!1e1!3m4!1sbHdd-94cz3CK0fKRHOfXEg!2e0!7i13312!8i6656)
Dual left turn lanes are often found at busy intersections from what I've noticed, so I don't think allowing this in Ontario would be worth the increased risk of side-swipes and hitting pedestrians.
https://www.google.ca/maps/@43.4284371,-80.4322768,3a,30y,40.12h,95.56t/data=!3m6!1e1!3m4!1sbHdd-94cz3CK0fKRHOfXEg!2e0!7i13312!8i6656 (https://www.google.ca/maps/@43.4284371,-80.4322768,3a,30y,40.12h,95.56t/data=!3m6!1e1!3m4!1sbHdd-94cz3CK0fKRHOfXEg!2e0!7i13312!8i6656)
Dual left turn lanes are often found at busy intersections from what I've noticed, so I don't think allowing this in Ontario would be worth the increased risk of side-swipes and hitting pedestrians.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: JMAN_WiS&S on July 16, 2016, 03:12:47 PM
Post by: JMAN_WiS&S on July 16, 2016, 03:12:47 PM
Clairemont Ave (US 12) in Eau Claire Wisconsin has dual left turns across 3 lanes of 45mph traffic and two intersections like this are getting protected/permissive FYA. not sure how it will go..
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on July 16, 2016, 03:40:13 PM
Post by: jakeroot on July 16, 2016, 03:40:13 PM
Quote from: roadfro on July 16, 2016, 12:35:02 PM
OT reply...Quote from: jakeroot on July 15, 2016, 05:48:55 PM
- Colorado (+1 for overhead signals using backplates but not side-mounted signals -- I think this looks better and makes the mast-arms less bulky).
Terms might be a bit jumbled here... The "mast arm" is the part of the traffic signal assembly that sticks out over the roadway (typically horizontally, but can also be curved as seen in California). The "mast" is the vertical pole to which the mast arm (and side-mounted signals, if present) are attached. So a side-mounted signal head missing a backplate wouldn't affect the look of a mast arm.
Whoops. Yes I meant "mast". Thanks for filling me in.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on April 21, 2017, 03:06:07 AM
Post by: jakeroot on April 21, 2017, 03:06:07 AM
Just gonna dust off this thread. Looking for some input from those familiar with Maryland.
I found a left turn in Silver Spring (Route 650 onto Columbia Pike). It's a dual left turn with a flashing red arrow, with turns permitted after a full stop.
I've read before that flashing red arrows are pretty ubiquitous in Maryland (versus flashing yellow arrows). I can tell from Street View that many single lefts have FRAs, but not many dual lefts.
Anyone know how often Maryland installs dual left flashing red arrows?
Here is the Gmaps link to the intersection below: https://goo.gl/Lr4gDD -- according to Historic Aerials, the second left turn lane was added in 2005.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FTxzxpIc.png&hash=c07edcd32f8ee2ae7324f14f9e90a527663432de)
I found a left turn in Silver Spring (Route 650 onto Columbia Pike). It's a dual left turn with a flashing red arrow, with turns permitted after a full stop.
I've read before that flashing red arrows are pretty ubiquitous in Maryland (versus flashing yellow arrows). I can tell from Street View that many single lefts have FRAs, but not many dual lefts.
Anyone know how often Maryland installs dual left flashing red arrows?
Here is the Gmaps link to the intersection below: https://goo.gl/Lr4gDD -- according to Historic Aerials, the second left turn lane was added in 2005.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FTxzxpIc.png&hash=c07edcd32f8ee2ae7324f14f9e90a527663432de)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: mrsman on April 30, 2017, 04:22:16 PM
Post by: mrsman on April 30, 2017, 04:22:16 PM
Quote from: jakeroot on April 21, 2017, 03:06:07 AM
Just gonna dust off this thread. Looking for some input from those familiar with Maryland.
I found a left turn in Silver Spring (Route 650 onto Columbia Pike). It's a dual left turn with a flashing red arrow, with turns permitted after a full stop.
I've read before that flashing red arrows are pretty ubiquitous in Maryland (versus flashing yellow arrows). I can tell from Street View that many single lefts have FRAs, but not many dual lefts.
Anyone know how often Maryland installs dual left flashing red arrows?
Here is the Gmaps link to the intersection below: https://goo.gl/Lr4gDD -- according to Historic Aerials, the second left turn lane was added in 2005.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FTxzxpIc.png&hash=c07edcd32f8ee2ae7324f14f9e90a527663432de)
While not an expert on MD per se, I am very familiar with this intersection as I drive by frequently.
I can say that this an exception as I cannot think of other permissive double lefts in MD anywhere. One factor how this may be safer than others is that this is a
T intersection. There is no corresponding left turn in the opposite direction, and you don't have to worry about cross traffic or right turns or anything. So if there are other dual left turn FRAs, they would only be in similar circumstances (on-ramp to freeway) and not a standard intersection.
FWIW, the visibility here is excellent. It is very easy to see SB traffic when making the left turn from NB NH ave to US 29 (from either lane). I believe before 2005, there was no traffic signal at all and for most hours of the day, except rush hour a singal was not needed. It seemed that there was enough of a backup during rush hours that they felt that a second lane was necessary and still provided an option for a protected signal. I give DOT a lot of credit for making this protected/permissive.
The normal operation of the signal is SB green and NB FRA. When there are enough who want to make the left, the SB signal goes from yellow to red. After a brief period NB left becomes a green arrow, then a yellow arrow, and then a solid red arrow for a few seconds while SB traffic is released with a green. And then FRA again.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on April 30, 2017, 07:29:05 PM
Post by: jakeroot on April 30, 2017, 07:29:05 PM
Quote from: mrsman on April 30, 2017, 04:22:16 PMQuote from: jakeroot on April 21, 2017, 03:06:07 AM
Just gonna dust off this thread. Looking for some input from those familiar with Maryland.
I found a left turn in Silver Spring (Route 650 onto Columbia Pike). It's a dual left turn with a flashing red arrow, with turns permitted after a full stop.
I've read before that flashing red arrows are pretty ubiquitous in Maryland (versus flashing yellow arrows). I can tell from Street View that many single lefts have FRAs, but not many dual lefts.
Anyone know how often Maryland installs dual left flashing red arrows?
Here is the Gmaps link to the intersection below: https://goo.gl/Lr4gDD -- according to Historic Aerials, the second left turn lane was added in 2005.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FTxzxpIc.png&hash=c07edcd32f8ee2ae7324f14f9e90a527663432de)
While not an expert on MD per se, I am very familiar with this intersection as I drive by frequently.
I can say that this an exception as I cannot think of other permissive double lefts in MD anywhere. One factor how this may be safer than others is that this is a
T intersection. There is no corresponding left turn in the opposite direction, and you don't have to worry about cross traffic or right turns or anything. So if there are other dual left turn FRAs, they would only be in similar circumstances (on-ramp to freeway) and not a standard intersection.
FWIW, the visibility here is excellent. It is very easy to see SB traffic when making the left turn from NB NH ave to US 29 (from either lane). I believe before 2005, there was no traffic signal at all and for most hours of the day, except rush hour a singal was not needed. It seemed that there was enough of a backup during rush hours that they felt that a second lane was necessary and still provided an option for a protected signal. I give DOT a lot of credit for making this protected/permissive.
The normal operation of the signal is SB green and NB FRA. When there are enough who want to make the left, the SB signal goes from yellow to red. After a brief period NB left becomes a green arrow, then a yellow arrow, and then a solid red arrow for a few seconds while SB traffic is released with a green. And then FRA again.
I'm really, really glad to hear these work well. Anybody who knows me, knows I really like permissive double lefts (mostly because I don't like protected lefts, period). Maryland's approach seems like a really good middle ground between flashing yellow, and protected-only. Particularly at Parclo B4s (such as in the Silver Spring example), where the only signalised movement is a left turn, they seem like a great candidate for FRAs (though only if the left is a double left -- I still prefer FYAs at single left turns.
As for the phasing, I'd have thought that going from FRA to green arrow would be acceptable (FRA to solid yellow seems a bit odd). But if the phasing described above is what Maryland has more success with, more power to them.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: mrsman on May 01, 2017, 03:04:51 PM
Post by: mrsman on May 01, 2017, 03:04:51 PM
Quote from: jakeroot on April 30, 2017, 07:29:05 PMQuote from: mrsman on April 30, 2017, 04:22:16 PMQuote from: jakeroot on April 21, 2017, 03:06:07 AM
Just gonna dust off this thread. Looking for some input from those familiar with Maryland.
I found a left turn in Silver Spring (Route 650 onto Columbia Pike). It's a dual left turn with a flashing red arrow, with turns permitted after a full stop.
I've read before that flashing red arrows are pretty ubiquitous in Maryland (versus flashing yellow arrows). I can tell from Street View that many single lefts have FRAs, but not many dual lefts.
Anyone know how often Maryland installs dual left flashing red arrows?
Here is the Gmaps link to the intersection below: https://goo.gl/Lr4gDD -- according to Historic Aerials, the second left turn lane was added in 2005.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FTxzxpIc.png&hash=c07edcd32f8ee2ae7324f14f9e90a527663432de)
While not an expert on MD per se, I am very familiar with this intersection as I drive by frequently.
I can say that this an exception as I cannot think of other permissive double lefts in MD anywhere. One factor how this may be safer than others is that this is a
T intersection. There is no corresponding left turn in the opposite direction, and you don't have to worry about cross traffic or right turns or anything. So if there are other dual left turn FRAs, they would only be in similar circumstances (on-ramp to freeway) and not a standard intersection.
FWIW, the visibility here is excellent. It is very easy to see SB traffic when making the left turn from NB NH ave to US 29 (from either lane). I believe before 2005, there was no traffic signal at all and for most hours of the day, except rush hour a singal was not needed. It seemed that there was enough of a backup during rush hours that they felt that a second lane was necessary and still provided an option for a protected signal. I give DOT a lot of credit for making this protected/permissive.
The normal operation of the signal is SB green and NB FRA. When there are enough who want to make the left, the SB signal goes from yellow to red. After a brief period NB left becomes a green arrow, then a yellow arrow, and then a solid red arrow for a few seconds while SB traffic is released with a green. And then FRA again.
I'm really, really glad to hear these work well. Anybody who knows me, knows I really like permissive double lefts (mostly because I don't like protected lefts, period). Maryland's approach seems like a really good middle ground between flashing yellow, and protected-only. Particularly at Parclo B4s (such as in the Silver Spring example), where the only signalised movement is a left turn, they seem like a great candidate for FRAs (though only if the left is a double left -- I still prefer FYAs at single left turns.
As for the phasing, I'd have thought that going from FRA to green arrow would be acceptable (FRA to solid yellow seems a bit odd). But if the phasing described above is what Maryland has more success with, more power to them.
I may not have been clear in my last post about the signaling. Hopefully this is better:
NB: SB:
FRA Green
FRA Yellow
FRA Red (one second)
green arrow Red
yellow arrow red
solid red arrow red (one second)
solid red arrow green (15 seconds)
FRA green
There is a brief period, about 15 seconds, when SB traffic is first released on the green that NB traffic may not turn left (solid red arrow).
There is no interval from FRA to yellow arrow. There is no indication from the NB side that SB gets a yellow ball. You sit at the intersection waiting to make a left and you may notice that some of the cars that are approaching SB are slowing or stopping. By the time you realize that the opposing side has a red, the green arrow comes on and you can go.
Of course NB thru traffic faces no signal whatsoever and is functionally equivalent to a continuous green.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on May 01, 2017, 03:08:02 PM
Post by: jakeroot on May 01, 2017, 03:08:02 PM
Quote from: mrsman on May 01, 2017, 03:04:51 PM
There is no interval from FRA to yellow arrow. There is no indication from the NB side that SB gets a yellow ball. You sit at the intersection waiting to make a left and you may notice that some of the cars that are approaching SB are slowing or stopping. By the time you realize that the opposing side has a red, the green arrow comes on and you can go.
I did misunderstand what you wrote. That you for the clarification. I got the SB and NB phasings mixed up.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on May 14, 2017, 05:00:59 PM
Post by: jakeroot on May 14, 2017, 05:00:59 PM
Here's a dual permissive left in Brooklyn, NY (a state with very few dual permissive lefts). The left turn signal is a traditional 5-section tower (common in NYC? I'm not sure):
Flatbush @ Tillary, Brooklyn (https://goo.gl/KkBZQT)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FFB31HyA.png&hash=6ba9e8d6624104f8e61b0696f9923383c0fc49ab)
Flatbush @ Tillary, Brooklyn (https://goo.gl/KkBZQT)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FFB31HyA.png&hash=6ba9e8d6624104f8e61b0696f9923383c0fc49ab)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: cl94 on May 14, 2017, 05:40:18 PM
Post by: cl94 on May 14, 2017, 05:40:18 PM
Quote from: jakeroot on May 14, 2017, 05:00:59 PM
Here's a dual permissive left in Brooklyn, NY (a state with very few dual permissive lefts). The left turn signal is a traditional 5-section tower (common in NYC? I'm not sure):
Flatbush @ Tillary, Brooklyn (https://goo.gl/KkBZQT)
The 5-section is the standard permissive signal in New York City. Another type is a 2-section 12" arrow face alongside a 3-section 8" face. I don't think there's a single doghouse inside the City.
Having family nearby until relatively recently, this was the only dual-permissive left turn installation I knew of anywhere until I was almost 9. It's still one of the less than 5 I have seen in person. I'm convinced that this was only done because opposing turns are prohibited and sightlines are wide-open. I do NOT know of another dual permissive left in New York that has opposing left turns (excluding the east end of Queens Blvd (https://www.google.com/maps/@40.7043938,-73.8154668,3a,75y,150.56h,77.42t/data=!3m6!1e1!3m4!1s_py5QYyiWGRB1Q4-xP_OzQ!2e0!7i13312!8i6656), which has open sightlines due to the way the WB ROW shifts).
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: mrsman on May 29, 2017, 07:22:16 PM
Post by: mrsman on May 29, 2017, 07:22:16 PM
Quote from: cl94 on May 14, 2017, 05:40:18 PMQuote from: jakeroot on May 14, 2017, 05:00:59 PM
Here's a dual permissive left in Brooklyn, NY (a state with very few dual permissive lefts). The left turn signal is a traditional 5-section tower (common in NYC? I'm not sure):
Flatbush @ Tillary, Brooklyn (https://goo.gl/KkBZQT)
The 5-section is the standard permissive signal in New York City. Another type is a 2-section 12" arrow face alongside a 3-section 8" face. I don't think there's a single doghouse inside the City.
Having family nearby until relatively recently, this was the only dual-permissive left turn installation I knew of anywhere until I was almost 9. It's still one of the less than 5 I have seen in person. I'm convinced that this was only done because opposing turns are prohibited and sightlines are wide-open. I do NOT know of another dual permissive left in New York that has opposing left turns (excluding the east end of Queens Blvd (https://www.google.com/maps/@40.7043938,-73.8154668,3a,75y,150.56h,77.42t/data=!3m6!1e1!3m4!1s_py5QYyiWGRB1Q4-xP_OzQ!2e0!7i13312!8i6656), which has open sightlines due to the way the WB ROW shifts).
There's a permissive dual option lane in NYC at Centre and Chambers on the Manhattan side off the Brooklyn Bridge:
https://www.google.com/maps/@40.7129151,-74.0042291,3a,75y,50.72h,79.23t/data=!3m6!1e1!3m4!1s5-CrH0LbXNFXaQhzIN7_nA!2e0!7i13312!8i6656
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: RestrictOnTheHanger on May 29, 2017, 11:47:45 PM
Post by: RestrictOnTheHanger on May 29, 2017, 11:47:45 PM
Quote from: mrsman on May 29, 2017, 07:22:16 PMQuote from: cl94 on May 14, 2017, 05:40:18 PMQuote from: jakeroot on May 14, 2017, 05:00:59 PM
Here's a dual permissive left in Brooklyn, NY (a state with very few dual permissive lefts). The left turn signal is a traditional 5-section tower (common in NYC? I'm not sure):
Flatbush @ Tillary, Brooklyn (https://goo.gl/KkBZQT)
The 5-section is the standard permissive signal in New York City. Another type is a 2-section 12" arrow face alongside a 3-section 8" face. I don't think there's a single doghouse inside the City.
Having family nearby until relatively recently, this was the only dual-permissive left turn installation I knew of anywhere until I was almost 9. It's still one of the less than 5 I have seen in person. I'm convinced that this was only done because opposing turns are prohibited and sightlines are wide-open. I do NOT know of another dual permissive left in New York that has opposing left turns (excluding the east end of Queens Blvd (https://www.google.com/maps/@40.7043938,-73.8154668,3a,75y,150.56h,77.42t/data=!3m6!1e1!3m4!1s_py5QYyiWGRB1Q4-xP_OzQ!2e0!7i13312!8i6656), which has open sightlines due to the way the WB ROW shifts).
There's a permissive dual option lane in NYC at Centre and Chambers on the Manhattan side off the Brooklyn Bridge:
https://www.google.com/maps/@40.7129151,-74.0042291,3a,75y,50.72h,79.23t/data=!3m6!1e1!3m4!1s5-CrH0LbXNFXaQhzIN7_nA!2e0!7i13312!8i6656
This is the only doghouse proper in NYC (excluding the airports which have signals maintained by PANYNJ), which also happens to be one of the few spanwire signals in NYC
Arthur Kill Rd, Staten Island
https://goo.gl/maps/6UPjSZra8nv
This setup by Queens Center Mall (https://goo.gl/maps/23Dn3y7yMcN2) is technically a dual permissive left, but left is the only way to go here. The signal sequence is
Red ball Green arrow -> Red ball Yellow arrow -> red ball -> green ball (opposing traffic gets a green and pedestrians get walk signs) -> yellow ball in both directions -> red ball in both directions
Flashing yellow arrows would do better here IMO since drivers must yield on the green ball phase and there is high pedestrian and opposing traffic.
There are also quite a few permissive left turn / left turn+thru option lane setups in NYC. Two that i know of are 108 st/ LIE service road (https://goo.gl/maps/buNmkTCsNQL2)(lagging left in both directions, lanes are a bit hard to see in streetview), and Junction Blvd s/b at the LIE (https://goo.gl/maps/Weg7bzQJGk72) (lagging left)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: US 89 on May 30, 2017, 06:18:47 PM
Post by: US 89 on May 30, 2017, 06:18:47 PM
I have never seen a dual permissive left in Utah, I think the state MUTCD bans them (but I could be wrong). I think they are a bad idea, because it makes for even more things to keep track of, and usually these intersections are already dangerous.
As for which permissive signal is used, FYA is used on newer lights around here, doghouses on older ones. I can think of only a couple 5-section verticals, which are usually ground-mounted (400 W and 200 S in SLC comes to mind).
EDIT: Although it is for a right turn, there's a 5-section head at St George Blvd and Bluff St in St George, Utah, mounted on the mast arm.
As for which permissive signal is used, FYA is used on newer lights around here, doghouses on older ones. I can think of only a couple 5-section verticals, which are usually ground-mounted (400 W and 200 S in SLC comes to mind).
EDIT: Although it is for a right turn, there's a 5-section head at St George Blvd and Bluff St in St George, Utah, mounted on the mast arm.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on June 03, 2017, 03:10:59 AM
Post by: jakeroot on June 03, 2017, 03:10:59 AM
Riiga, this may interest you more than me. Here's a double permissive left turn in Denmark. Cruising around Denmark, they appear to have more than a few of these. There's none in Sweden, right?
The best part of this is that I'm predominantly Danish (my Great Great Grandmother emigrated from Denmark). Double permissive lefts run in my blood!
Street View: https://goo.gl/ZVmRpX (Røde Mellemvej @ Vejlands Allé, südlich von Kopenhagen)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FOxyf5ca.png&hash=7f0e495dbb7aaaedd92e3e2f0b51bb553d5d6784)
The best part of this is that I'm predominantly Danish (my Great Great Grandmother emigrated from Denmark). Double permissive lefts run in my blood!
Street View: https://goo.gl/ZVmRpX (Røde Mellemvej @ Vejlands Allé, südlich von Kopenhagen)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FOxyf5ca.png&hash=7f0e495dbb7aaaedd92e3e2f0b51bb553d5d6784)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: riiga on June 03, 2017, 07:30:51 AM
Post by: riiga on June 03, 2017, 07:30:51 AM
Quote from: jakeroot on June 03, 2017, 03:10:59 AM
Riiga, this may interest you more than me. Here's a double permissive left turn in Denmark. Cruising around Denmark, they appear to have more than a few of these. There's none in Sweden, right?
Very interesting, typically I associate Denmark with separated protected left turns, like this (https://www.google.com/maps/@55.6710258,12.4554156,3a,25.8y,81.7h,86.47t/data=!3m6!1e1!3m4!1sGuzv7g0XDZlpo5O9BCAqsg!2e0!7i13312!8i6656) or this (https://www.google.com/maps/@55.6706014,12.4565737,3a,41y,351.99h,85.14t/data=!3m6!1e1!3m4!1s2usvwLlqtHTcQyAG8GsH_Q!2e0!7i13312!8i6656) (semi-protected). I've dubbed them "Danish turn lane" due to their tendency to separate them by wide paint or a barrier, something I rarely see in Sweden.
As for as I know, there are no dual permissive left turns in Sweden. At speeds >50 km/h signal regulated permissive turns are not allowed, but must use a left turn arrow instead, and dual turn lanes are quite uncommon in cities, and when they exist I'm pretty sure they're all protected turns. I've come across some regulations related to left turns, but it seems the closest we have to permissive left turns are dual left turns using circular lights with no oncoming traffic. Translated below for reference.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FhoUE0uZ.png&hash=0477f5b5949540a500f2b300aedab972267a7b0b)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on June 03, 2017, 07:22:30 PM
Post by: jakeroot on June 03, 2017, 07:22:30 PM
Quote from: riiga on June 03, 2017, 07:30:51 AMQuote from: jakeroot on June 03, 2017, 03:10:59 AM
Riiga, this may interest you more than me. Here's a double permissive left turn in Denmark. Cruising around Denmark, they appear to have more than a few of these. There's none in Sweden, right?
Very interesting, typically I associate Denmark with separated protected left turns, like this (https://www.google.com/maps/@55.6710258,12.4554156,3a,25.8y,81.7h,86.47t/data=!3m6!1e1!3m4!1sGuzv7g0XDZlpo5O9BCAqsg!2e0!7i13312!8i6656) or this (https://www.google.com/maps/@55.6706014,12.4565737,3a,41y,351.99h,85.14t/data=!3m6!1e1!3m4!1s2usvwLlqtHTcQyAG8GsH_Q!2e0!7i13312!8i6656) (semi-protected). I've dubbed them "Danish turn lane" due to their tendency to separate them by wide paint or a barrier, something I rarely see in Sweden.
I also noticed this while browsing around. In particular, the primary roads have left turn lanes separated by either a barrier or paint, but the side roads have everything smushed together (with a barrier only between opposing directions), like in the image above. I wasn't able to find any double permissive turns from a primary road, but several from a side street (that would otherwise have a yield sign). Here's one with a option lane: https://goo.gl/gTNQ7n (no visible red arrow signals, so I assume it's a permissive left).
Quote from: riiga on June 03, 2017, 07:30:51 AM
As for as I know, there are no dual permissive left turns in Sweden. At speeds >50 km/h signal regulated permissive turns are not allowed, but must use a left turn arrow instead, and dual turn lanes are quite uncommon in cities, and when they exist I'm pretty sure they're all protected turns. I've come across some regulations related to left turns, but it seems the closest we have to permissive left turns are dual left turns using circular lights with no oncoming traffic. Translated below for reference.
http://i.imgur.com/hoUE0uZ.png
Dual turn lanes are also uncommon in the UK. Seems like older places just don't have the room for them.
So it looks like "split phasing" is used at these option-lane left turns?
Interesting that 50 km/h is the maximum for permissive lefts. Some states have limits on permissive lefts (usually speed limit ≤ 70 km/h), but I'm unaware of a state with a 50 km/h limit (though that's just for the state -- individual cities are free to do as they wish). 50 km/h seems kind of low to me.
Aviation Parkway in Tucson, Arizona is a 90 km/h road with permissive lefts: https://goo.gl/KxGp3E. Very few roads with this high of a limit have signals in the US, so this must be one of the highest posted roads with permissive lefts.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: cl94 on June 03, 2017, 08:25:08 PM
Post by: cl94 on June 03, 2017, 08:25:08 PM
Quote from: jakeroot on June 03, 2017, 07:22:30 PMQuote from: riiga on June 03, 2017, 07:30:51 AMQuote from: jakeroot on June 03, 2017, 03:10:59 AM
Riiga, this may interest you more than me. Here's a double permissive left turn in Denmark. Cruising around Denmark, they appear to have more than a few of these. There's none in Sweden, right?
Very interesting, typically I associate Denmark with separated protected left turns, like this (https://www.google.com/maps/@55.6710258,12.4554156,3a,25.8y,81.7h,86.47t/data=!3m6!1e1!3m4!1sGuzv7g0XDZlpo5O9BCAqsg!2e0!7i13312!8i6656) or this (https://www.google.com/maps/@55.6706014,12.4565737,3a,41y,351.99h,85.14t/data=!3m6!1e1!3m4!1s2usvwLlqtHTcQyAG8GsH_Q!2e0!7i13312!8i6656) (semi-protected). I've dubbed them "Danish turn lane" due to their tendency to separate them by wide paint or a barrier, something I rarely see in Sweden.
I also noticed this while browsing around. In particular, the primary roads have left turn lanes separated by either a barrier or paint, but the side roads have everything smushed together (with a barrier only between opposing directions), like in the image above. I wasn't able to find any double permissive turns from a primary road, but several from a side street (that would otherwise have a yield sign). Here's one with a option lane: https://goo.gl/gTNQ7n (no visible red arrow signals, so I assume it's a permissive left).Quote from: riiga on June 03, 2017, 07:30:51 AM
As for as I know, there are no dual permissive left turns in Sweden. At speeds >50 km/h signal regulated permissive turns are not allowed, but must use a left turn arrow instead, and dual turn lanes are quite uncommon in cities, and when they exist I'm pretty sure they're all protected turns. I've come across some regulations related to left turns, but it seems the closest we have to permissive left turns are dual left turns using circular lights with no oncoming traffic. Translated below for reference.
http://i.imgur.com/hoUE0uZ.png
Dual turn lanes are also uncommon in the UK. Seems like older places just don't have the room for them.
So it looks like "split phasing" is used at these option-lane left turns?
Interesting that 50 km/h is the maximum for permissive lefts. Some states have limits on permissive lefts (usually speed limit ≤ 70 km/h), but I'm unaware of a state with a 50 km/h limit (though that's just for the state -- individual cities are free to do as they wish). 50 km/h seems kind of low to me.
Aviation Parkway in Tucson, Arizona is a 90 km/h road with permissive lefts: https://goo.gl/KxGp3E. Very few roads with this high of a limit have signals in the US, so this must be one of the highest posted roads with permissive lefts.
I wouldn't say it's uncommon to see signals or permissive lefts on a road posted at 55 mph (90 km/h), definitely not in the northeast and midwest. Ohio allows signalized at-grades on roads posted up to 60 (mostly protected, but I have seen a couple permissive) and unsignalized at-grades up to 70. New Jersey divided highways are often 55, signals or "Jersey Freeway". Default for New York is 55 (co-posted as 90 km/h in a couple places) and it doesn't go down for signals. NY's 55 roads generally have permissive lefts.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on June 03, 2017, 09:59:24 PM
Post by: jakeroot on June 03, 2017, 09:59:24 PM
Quote from: cl94 on June 03, 2017, 08:25:08 PMQuote from: jakeroot on June 03, 2017, 07:22:30 PMQuote from: riiga on June 03, 2017, 07:30:51 AM
As for as I know, there are no dual permissive left turns in Sweden. At speeds >50 km/h signal regulated permissive turns are not allowed, but must use a left turn arrow instead, and dual turn lanes are quite uncommon in cities, and when they exist I'm pretty sure they're all protected turns. I've come across some regulations related to left turns, but it seems the closest we have to permissive left turns are dual left turns using circular lights with no oncoming traffic. Translated below for reference.
http://i.imgur.com/hoUE0uZ.png
Dual turn lanes are also uncommon in the UK. Seems like older places just don't have the room for them.
So it looks like "split phasing" is used at these option-lane left turns?
Interesting that 50 km/h is the maximum for permissive lefts. Some states have limits on permissive lefts (usually speed limit ≤ 70 km/h), but I'm unaware of a state with a 50 km/h limit (though that's just for the state -- individual cities are free to do as they wish). 50 km/h seems kind of low to me.
Aviation Parkway in Tucson, Arizona is a 90 km/h road with permissive lefts: https://goo.gl/KxGp3E. Very few roads with this high of a limit have signals in the US, so this must be one of the highest posted roads with permissive lefts.
I wouldn't say it's uncommon to see signals or permissive lefts on a road posted at 55 mph (90 km/h), definitely not in the northeast and midwest. Ohio allows signalized at-grades on roads posted up to 60 (mostly protected, but I have seen a couple permissive) and unsignalized at-grades up to 70. New Jersey divided highways are often 55, signals or "Jersey Freeway". Default for New York is 55 (co-posted as 90 km/h in a couple places) and it doesn't go down for signals. NY's 55 roads generally have permissive lefts.
After doing a bit of research, it appears that my comment was (a bit) unfounded. :pan: Even Washington has several high speed roads with permissive lefts. I guess I forgot about them.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: US 89 on June 03, 2017, 11:44:30 PM
Post by: US 89 on June 03, 2017, 11:44:30 PM
Quote from: jakeroot on June 03, 2017, 09:59:24 PMQuote from: cl94 on June 03, 2017, 08:25:08 PMQuote from: jakeroot on June 03, 2017, 07:22:30 PMQuote from: riiga on June 03, 2017, 07:30:51 AM
As for as I know, there are no dual permissive left turns in Sweden. At speeds >50 km/h signal regulated permissive turns are not allowed, but must use a left turn arrow instead, and dual turn lanes are quite uncommon in cities, and when they exist I'm pretty sure they're all protected turns. I've come across some regulations related to left turns, but it seems the closest we have to permissive left turns are dual left turns using circular lights with no oncoming traffic. Translated below for reference.
http://i.imgur.com/hoUE0uZ.png
Dual turn lanes are also uncommon in the UK. Seems like older places just don't have the room for them.
So it looks like "split phasing" is used at these option-lane left turns?
Interesting that 50 km/h is the maximum for permissive lefts. Some states have limits on permissive lefts (usually speed limit ≤ 70 km/h), but I'm unaware of a state with a 50 km/h limit (though that's just for the state -- individual cities are free to do as they wish). 50 km/h seems kind of low to me.
Aviation Parkway in Tucson, Arizona is a 90 km/h road with permissive lefts: https://goo.gl/KxGp3E. Very few roads with this high of a limit have signals in the US, so this must be one of the highest posted roads with permissive lefts.
I wouldn't say it's uncommon to see signals or permissive lefts on a road posted at 55 mph (90 km/h), definitely not in the northeast and midwest. Ohio allows signalized at-grades on roads posted up to 60 (mostly protected, but I have seen a couple permissive) and unsignalized at-grades up to 70. New Jersey divided highways are often 55, signals or "Jersey Freeway". Default for New York is 55 (co-posted as 90 km/h in a couple places) and it doesn't go down for signals. NY's 55 roads generally have permissive lefts.
After doing a bit of research, it appears that my comment was (a bit) unfounded. :pan: Even Washington has several high speed roads with permissive lefts. I guess I forgot about them.
In Utah, a protected left is required if the speed limit is 60 or higher, and protected lefts are required for dual left turn lanes. https://www.udot.utah.gov/main/uconowner.gf?n=22168023889671869 (https://www.udot.utah.gov/main/uconowner.gf?n=22168023889671869)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: riiga on June 09, 2017, 06:29:45 PM
Post by: riiga on June 09, 2017, 06:29:45 PM
Quote from: jakeroot on June 03, 2017, 07:22:30 PMIndeed, looks like a permissive left setup with a short protected phase (the lower left signal has an extra light for the green arrow).
Here's one with a option lane: https://goo.gl/gTNQ7n (no visible red arrow signals, so I assume it's a permissive left).
Quote from: jakeroot on June 03, 2017, 07:22:30 PMMost probably. Never seen one of them in real life though, only single permissive lefts.
So it looks like "split phasing" is used at these option-lane left turns?
Quote from: jakeroot on June 03, 2017, 07:22:30 PMWell, we don't allow signals at all above 70 km/h, so I think it makes sense to keep permissive turns to city traffic (where you would expect a 50 km/h limit). Permissive turns at >60 km/h also seems like a great way to cause accidents. ;-)
Interesting that 50 km/h is the maximum for permissive lefts. Some states have limits on permissive lefts (usually speed limit ≤ 70 km/h), but I'm unaware of a state with a 50 km/h limit (though that's just for the state -- individual cities are free to do as they wish). 50 km/h seems kind of low to me.
Outside of cities we tend to favor this type of offset junction (https://www.google.se/maps/@58.293344,15.8936128,3a,39.2y,149.27h,83.22t/data=!3m6!1e1!3m4!1s6mhgcW7vxiAkZTfxH9D8Eg!2e0!7i13312!8i6656). Traffic volumes are rarely a problem here, so signals outside of city limits are very rare. I know of one that sort of counts (https://www.google.se/maps/@58.9816552,14.6234923,3a,49y,59.24h,84.16t/data=!3m7!1e1!3m5!1szst2HcMSGG5MT1zygCOYxw!2e0!5s20100901T000000!7i13312!8i6656), now replaced by a roundabout.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on June 11, 2017, 08:08:28 PM
Post by: jakeroot on June 11, 2017, 08:08:28 PM
Quote from: riiga on June 09, 2017, 06:29:45 PM
[W]e don't allow signals at all above 70 km/h, so I think it makes sense to keep permissive turns to city traffic (where you would expect a 50 km/h limit). Permissive turns at >60 km/h also seems like a great way to cause accidents.
I've seen studies that show permissive signals to be safer than protected-only signals, because drivers are less impatient. A city near me (Federal Way, WA) recently switched all their protected lefts for protected/permissive lefts, and they saw a marked drop in collisions. People weren't "pushing the lights" like they were before.
Quote from: riiga on June 09, 2017, 06:29:45 PM
Outside of cities we tend to favor this type of offset junction (https://www.google.se/maps/@58.293344,15.8936128,3a,39.2y,149.27h,83.22t/data=!3m6!1e1!3m4!1s6mhgcW7vxiAkZTfxH9D8Eg!2e0!7i13312!8i6656). Traffic volumes are rarely a problem here, so signals outside of city limits are very rare. I know of one that sort of counts (https://www.google.se/maps/@58.9816552,14.6234923,3a,49y,59.24h,84.16t/data=!3m7!1e1!3m5!1szst2HcMSGG5MT1zygCOYxw!2e0!5s20100901T000000!7i13312!8i6656), now replaced by a roundabout.
Rural areas are certainly no place for signals (lest it's a very busy road and no money exists for grade-separation). Offset junctions are decidedly rare in the US (mostly due to rural roads being plotted in exactly straight lines), but they should be more common. It makes it way easier to cross a busy highway, and is almost certainly safer than having to look both ways and flooring it.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Brian556 on June 11, 2017, 08:46:21 PM
Post by: Brian556 on June 11, 2017, 08:46:21 PM
Here's a FYA dual left turn on Sandy Lake Rd at Denton Tap Rd in Coppell, TX:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi1209.photobucket.com%2Falbums%2Fcc395%2FBrian5561%2F6.11.2017%2520023_zpscmx2buv1.jpg&hash=b17162c831236aa7284192db2dfc54bcac915e4c) (http://s1209.photobucket.com/user/Brian5561/media/6.11.2017%20023_zpscmx2buv1.jpg.html)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi1209.photobucket.com%2Falbums%2Fcc395%2FBrian5561%2F6.11.2017%2520023_zpscmx2buv1.jpg&hash=b17162c831236aa7284192db2dfc54bcac915e4c) (http://s1209.photobucket.com/user/Brian5561/media/6.11.2017%20023_zpscmx2buv1.jpg.html)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on June 11, 2017, 11:21:21 PM
Post by: jakeroot on June 11, 2017, 11:21:21 PM
I'm glad to see them pop up, but I really wish the turns (^^ above) had a positive offset, a la Wisconsin or Tucson. The ones above have a negative offset, which creates rather poor visibility. You can still maintain a median between directions, just perhaps a smaller one.
I only suggest having positive offset because the double permissive leader, Tucson, suggests it, and their's seem to operate remarkably well, given the high volumes of traffic on their arterial roads.
I only suggest having positive offset because the double permissive leader, Tucson, suggests it, and their's seem to operate remarkably well, given the high volumes of traffic on their arterial roads.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Brian556 on June 12, 2017, 12:44:39 AM
Post by: Brian556 on June 12, 2017, 12:44:39 AM
Quote from jakeroot:
Heck, around here, most divided highway left turns have crappy visibility if the oncoming turn lane is occupied. Never mind a double turn.
This is in front of my neighborhood, and tis the worst one in our area:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi1209.photobucket.com%2Falbums%2Fcc395%2FBrian5561%2F6242014024_zps0f2f29f1.jpg&hash=d22f205db4a699a526d6c89c3695edd62d517c6a) (http://s1209.photobucket.com/user/Brian5561/media/6242014024_zps0f2f29f1.jpg.html)
Its awkward when the FYA's are installed because they also change the operation of the signals, allowing a permissive left while the oncoming traffic has a green ball and green arrow.
QuoteI'm glad to see them pop up, but I really wish the turns (^^ above) had a positive offset, a la Wisconsin or Tucson. The ones above have a negative offset, which creates rather poor visibility. You can still maintain a median between directions, just perhaps a smaller one.
I only suggest having positive offset because the double permissive leader, Tucson, suggests it, and their's seem to operate remarkably well, given the high volumes of traffic on their arterial roads.
Heck, around here, most divided highway left turns have crappy visibility if the oncoming turn lane is occupied. Never mind a double turn.
This is in front of my neighborhood, and tis the worst one in our area:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi1209.photobucket.com%2Falbums%2Fcc395%2FBrian5561%2F6242014024_zps0f2f29f1.jpg&hash=d22f205db4a699a526d6c89c3695edd62d517c6a) (http://s1209.photobucket.com/user/Brian5561/media/6242014024_zps0f2f29f1.jpg.html)
Its awkward when the FYA's are installed because they also change the operation of the signals, allowing a permissive left while the oncoming traffic has a green ball and green arrow.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: roadfro on June 12, 2017, 03:49:03 AM
Post by: roadfro on June 12, 2017, 03:49:03 AM
Quote from: Brian556 on June 12, 2017, 12:44:39 AM
Its awkward when the FYA's are installed because they also change the operation of the signals, allowing a permissive left while the oncoming traffic has a green ball and green arrow.
That's part of the point of FYA: FYA is tied to the opposing green (instead of the adjacent green), providing greater efficiency by allowing permissive turns in more situations than a standard doghouse.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on June 12, 2017, 11:02:50 PM
Post by: jakeroot on June 12, 2017, 11:02:50 PM
Quote from: Brian556 on June 12, 2017, 12:44:39 AM
Heck, around here, most divided highway left turns have crappy visibility if the oncoming turn lane is occupied. Never mind a double turn.
This is in front of my neighborhood, and tis the worst one in our area:
http://i1209.photobucket.com/albums/cc395/Brian5561/6242014024_zps0f2f29f1.jpg
Those types of left turns (negative offset, like in your image) are the ones that especially need waiting lines (dotted lines in the road that indicate where drivers should wait for oncoming traffic) (examples provided below). People typically pull straight out into the intersection when waiting to turn left. This is not good for visibility*. Optimal visibility (with negative offset left turns) is at the point when you are physically closest to oncoming traffic. Positioning your hood to be nearly on the left edge of the left lane of oncoming traffic sounds like a bad idea, but visibility is exceptionally good at this angle. If you watch any dash cam footage from places like the UK, Japan, or South Africa (both which have a lot of permissive turns), you'll see that this is where they wait.
Here are some examples of waiting lines (first from Japan, second from South Africa, third from Tucson). Note that all require waiting at an angle. The first two examples are standard road markings in those countries:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FadEp0Jr.png&hash=aea6bf8e5b7de7c1816b8538bb0036f9a3e589c5)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FY2MoGUG.png&hash=8175af12790d5a22d1d149dcedd13f67949aebc9)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FhXBZuOx.png&hash=e6941875f5d0f0141cf3ed9ac2eb2c0c923eaa50)
*This method of turning left originated from the idea that sitting at an angle puts you in a position to get pushed into oncoming traffic when waiting to turn left, in the event of a rear-end crash. While I have no data that shows this to be a false theory, I've also never seen any data that shows it to be true (it seems to be based on an idea of what could happen, rather than something that actually has).
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: US 89 on June 13, 2017, 12:44:17 AM
Post by: US 89 on June 13, 2017, 12:44:17 AM
Quote from: jakeroot on June 12, 2017, 11:02:50 PMQuote from: Brian556 on June 12, 2017, 12:44:39 AM
Heck, around here, most divided highway left turns have crappy visibility if the oncoming turn lane is occupied. Never mind a double turn.
This is in front of my neighborhood, and tis the worst one in our area:
http://i1209.photobucket.com/albums/cc395/Brian5561/6242014024_zps0f2f29f1.jpg
Those types of left turns (negative offset, like in your image) are the ones that especially need waiting lines (dotted lines in the road that indicate where drivers should wait for oncoming traffic) (examples provided below). People typically pull straight out into the intersection when waiting to turn left. This is not good for visibility*. Optimal visibility (with negative offset left turns) is at the point when you are physically closest to oncoming traffic. Positioning your hood to be nearly on the left edge of the left lane of oncoming traffic sounds like a bad idea, but visibility is exceptionally good at this angle. If you watch any dash cam footage from places like the UK, Japan, or South Africa (both which have a lot of permissive turns), you'll see that this is where they wait.
Here are some examples of waiting lines (first from Japan, second from South Africa, third from Tucson). Note that all require waiting at an angle. The first two examples are standard road markings in those countries:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FadEp0Jr.png&hash=aea6bf8e5b7de7c1816b8538bb0036f9a3e589c5)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FY2MoGUG.png&hash=8175af12790d5a22d1d149dcedd13f67949aebc9)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FhXBZuOx.png&hash=e6941875f5d0f0141cf3ed9ac2eb2c0c923eaa50)
*This method of turning left originated from the idea that sitting at an angle puts you in a position to get pushed into oncoming traffic when waiting to turn left, in the event of a rear-end crash. While I have no data that shows this to be a false theory, I've also never seen any data that shows it to be true (it seems to be based on an idea of what could happen, rather than something that actually has).
I have never heard of this, but it makes so much sense. I wish lines like those were standard practice in the US. There are several intersections around here where visibility is an issue.
However, there are a few problems I can see with this. One is that a lot of our roads don't have that wide median in the third photo, so there wouldn't necessarily be room to position yourself like that.
The other problem is that normally, if you slightly overshoot the stop line at a normal intersection, no big deal. If you misjudge or overshoot this line, you will almost certainly have a head on collision.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on June 13, 2017, 01:14:22 AM
Post by: jakeroot on June 13, 2017, 01:14:22 AM
Quote from: roadguy2 on June 13, 2017, 12:44:17 AMQuote from: jakeroot on June 12, 2017, 11:02:50 PMQuote from: Brian556 on June 12, 2017, 12:44:39 AM
Heck, around here, most divided highway left turns have crappy visibility if the oncoming turn lane is occupied. Never mind a double turn.
This is in front of my neighborhood, and tis the worst one in our area:
http://i1209.photobucket.com/albums/cc395/Brian5561/6242014024_zps0f2f29f1.jpg
Those types of left turns (negative offset, like in your image) are the ones that especially need waiting lines (dotted lines in the road that indicate where drivers should wait for oncoming traffic) (examples provided below). People typically pull straight out into the intersection when waiting to turn left. This is not good for visibility*. Optimal visibility (with negative offset left turns) is at the point when you are physically closest to oncoming traffic. Positioning your hood to be nearly on the left edge of the left lane of oncoming traffic sounds like a bad idea, but visibility is exceptionally good at this angle. If you watch any dash cam footage from places like the UK, Japan, or South Africa (both which have a lot of permissive turns), you'll see that this is where they wait.
I have never heard of this, but it makes so much sense. I wish lines like those were standard practice in the US. There are several intersections around here where visibility is an issue.
As far as I know, the example from Tucson (the last image) is the only use of this type of line anywhere in the US. I haven't bothered to check with the head of traffic control in Tucson, but I'd really like to know where he got the idea (though I have some ideas, as you might imagine).
Quote from: roadguy2 on June 13, 2017, 12:44:17 AM
However, there are a few problems I can see with this. One is that a lot of our roads don't have that wide median in the third photo, so there wouldn't necessarily be room to position yourself like that....The other problem is that normally, if you slightly overshoot the stop line at a normal intersection, no big deal. If you misjudge or overshoot this line, you will almost certainly have a head on collision.
They wouldn't really be necessary when the turn lanes are pointed straight at each other, or when there was positive offset. Though in any case, they come in handy, especially when there's a double left yield (rare, but a waiting line to prevent the outer lane from blocking the inner lane's sightlines would be helpful). This was discussed up-thread.
The idea of "overshooting" the waiting line is possible, but turning straight into oncoming traffic is possible today even without the line. If anything, the line is a helpful reminder of, not only how far you can go without getting in the way of anyone, but also that the turn is a yield situation (unless there's an overriding signal). I suspect failure-to-give way collisions would actually drop after implementation, but I have no way of knowing for sure.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on June 13, 2017, 04:21:09 PM
Post by: jakeroot on June 13, 2017, 04:21:09 PM
Just decided the check the poll.
Surprisingly close.
The real surprise? 15% of those polled, picked "cat".
wtf
Surprisingly close.
The real surprise? 15% of those polled, picked "cat".
wtf
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: US 89 on June 13, 2017, 05:29:35 PM
Post by: US 89 on June 13, 2017, 05:29:35 PM
Quote from: jakeroot on June 13, 2017, 04:21:09 PM
Just decided the check the poll.
Surprisingly close.
The real surprise? 15% of those polled, picked "cat".
wtf
Does that mean there are 2 left turn lanes, but really there's only one because there's a cat sitting in one of them? :)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on June 13, 2017, 05:48:44 PM
Post by: jakeroot on June 13, 2017, 05:48:44 PM
Quote from: roadguy2 on June 13, 2017, 05:29:35 PMQuote from: jakeroot on June 13, 2017, 04:21:09 PM
Just decided the check the poll.
Surprisingly close.
The real surprise? 15% of those polled, picked "cat".
wtf
Does that mean there are 2 left turn lanes, but really there's only one because there's a cat sitting in one of them? :)
:crazy:
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Revive 755 on September 29, 2017, 10:01:11 PM
Post by: Revive 755 on September 29, 2017, 10:01:11 PM
Found a protected-permissive dual left in Ankeny, Iowa for US 69/Ankeny Boulvard at 1st Street that uses two five-section towers: Streetview (https://www.google.com/maps/@41.7319437,-93.6002988,3a,53.1y,241.2h,87.79t/data=!3m6!1e1!3m4!1sW48hhj3RFDsCQQd91BG8OQ!2e0!7i13312!8i6656?hl=en)
The Des Moines newspaper though indicates this will be changed to a single left. http://www.desmoinesregister.com/story/news/local/ankeny/2017/09/29/ankeny-boulevard-and-1st-street-improvements-coming-2020/718133001/ (http://www.desmoinesregister.com/story/news/local/ankeny/2017/09/29/ankeny-boulevard-and-1st-street-improvements-coming-2020/718133001/)
The Des Moines newspaper though indicates this will be changed to a single left. http://www.desmoinesregister.com/story/news/local/ankeny/2017/09/29/ankeny-boulevard-and-1st-street-improvements-coming-2020/718133001/ (http://www.desmoinesregister.com/story/news/local/ankeny/2017/09/29/ankeny-boulevard-and-1st-street-improvements-coming-2020/718133001/)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: MNHighwayMan on September 29, 2017, 11:56:48 PM
Post by: MNHighwayMan on September 29, 2017, 11:56:48 PM
Having been through that intersection a few times, yeah, it can be a bit hairy. I never understood the reason for there being two left turn lanes onto SB US-69 (Ankeny Blvd).
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on September 30, 2017, 12:12:12 AM
Post by: jakeroot on September 30, 2017, 12:12:12 AM
Doesn't look like a well-designed double left (the outer left turn appears to conflict with the opposing left). Nevermind the poor visibility. Can't blame them for switching to a single left setup. At least they aren't changing it to protected-only.
Title: Re: Dual Left Permissive Turns (FYA or Doghouse)
Post by: jakeroot on October 19, 2017, 12:48:19 AM
Post by: jakeroot on October 19, 2017, 12:48:19 AM
Quote from: Ace10 on December 14, 2015, 02:50:35 AM
I grew up learning how to drive on the Gulf Coast in Mississippi, where there are apparently still at least three intersections with dual permissive lefts (which are at (1) Popps Ferry Rd and Cedar Lake Blvd in Biloxi (https://www.google.com/maps/@30.4427198,-88.9340841,3a,25.2y,100.48h,94.83t/data=!3m7!1e1!3m5!1s_m5f6Xth4tFpZ7ip5RL-iQ!2e0!6s%2F%2Fgeo2.ggpht.com%2Fcbk%3Fpanoid%3D_m5f6Xth4tFpZ7ip5RL-iQ%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D349.53455%26pitch%3D0!7i13312!8i6656), (2) MS 605 (Cowan Rd) and Pass Rd in Gulfport (https://www.google.com/maps/@30.3988569,-89.0264069,3a,75y,237.5h,73t/data=!3m6!1e1!3m4!1shOAIdXHebJXgkPDDAWWhtQ!2e0!7i13312!8i6656), and (3) WB Rodriguez St to SB I-110 in D'Iberville (https://www.google.com/maps/@30.4299739,-88.8952032,3a,51.4y,328.8h,78.59t/data=!3m6!1e1!3m4!1sePRTO65c04J-24bpTz_XWA!2e0!7i13312!8i6656) (see lane markings)).
Just an update. All three of the intersections you posted have been updated. Intersections one and two have been changed to protected only, whereas the third now has mast-arms with new signals (still doghouses for the double left, thank God).
In the first example, they widened Popps Ferry Road and changed the signal phasing. They could have easily aligned the WB left turn so that it was offset to the left (improving visibility for EB turning traffic). But, I guess they decided protected was good enough! Oh well.
Quote from: Ace10 on December 14, 2015, 02:50:35 AM
Since then, I think the only other place I've seen them is Duluth, Minnesota, but since Minnesota is the place I think I've seen the most FYAs outside of Oregon and Washington, there are probably more lurking about.
Do you remember where this was? I've was looking at a map of Duluth, when I remembered this post. But I cannot find any dual permissive lefts in Duluth. I have seen quite a few dual FYA displays elsewhere in Minnesota IRL, but they all ran protected-only. Not sure what MnDOT policy is nowadays.
Title: Re: Dual Left Permissive Turns (FYA or Doghouse)
Post by: JMAN_WiS&S on October 24, 2017, 06:09:33 PM
Post by: JMAN_WiS&S on October 24, 2017, 06:09:33 PM
Quote from: jakeroot on October 19, 2017, 12:48:19 AMQuote from: Ace10 on December 14, 2015, 02:50:35 AM
I grew up learning how to drive on the Gulf Coast in Mississippi, where there are apparently still at least three intersections with dual permissive lefts (which are at (1) Popps Ferry Rd and Cedar Lake Blvd in Biloxi (https://www.google.com/maps/@30.4427198,-88.9340841,3a,25.2y,100.48h,94.83t/data=!3m7!1e1!3m5!1s_m5f6Xth4tFpZ7ip5RL-iQ!2e0!6s%2F%2Fgeo2.ggpht.com%2Fcbk%3Fpanoid%3D_m5f6Xth4tFpZ7ip5RL-iQ%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D349.53455%26pitch%3D0!7i13312!8i6656), (2) MS 605 (Cowan Rd) and Pass Rd in Gulfport (https://www.google.com/maps/@30.3988569,-89.0264069,3a,75y,237.5h,73t/data=!3m6!1e1!3m4!1shOAIdXHebJXgkPDDAWWhtQ!2e0!7i13312!8i6656), and (3) WB Rodriguez St to SB I-110 in D'Iberville (https://www.google.com/maps/@30.4299739,-88.8952032,3a,51.4y,328.8h,78.59t/data=!3m6!1e1!3m4!1sePRTO65c04J-24bpTz_XWA!2e0!7i13312!8i6656) (see lane markings)).
Just an update. All three of the intersections you posted have been updated. Intersections one and two have been changed to protected only, whereas the third now has mast-arms with new signals (still doghouses for the double left, thank God).
In the first example, they widened Popps Ferry Road and changed the signal phasing. They could have easily aligned the WB left turn so that it was offset to the left (improving visibility for EB turning traffic). But, I guess they decided protected was good enough! Oh well.Quote from: Ace10 on December 14, 2015, 02:50:35 AM
Since then, I think the only other place I've seen them is Duluth, Minnesota, but since Minnesota is the place I think I've seen the most FYAs outside of Oregon and Washington, there are probably more lurking about.
Do you remember where this was? I've was looking at a map of Duluth, when I remembered this post. But I cannot find any dual permissive lefts in Duluth. I have seen quite a few dual FYA displays elsewhere in Minnesota IRL, but they all ran protected-only. Not sure what MnDOT policy is nowadays.
Isn't MnDOT's policy nowadays to instal 4 section FYA displays for ALL left turn signal movements, even if the signal is intended to only be operated in Protected mode?
Title: Re: Dual Left Permissive Turns (FYA or Doghouse)
Post by: jakeroot on October 24, 2017, 09:47:09 PM
Post by: jakeroot on October 24, 2017, 09:47:09 PM
Quote from: JMAN12343610 on October 24, 2017, 06:09:33 PMQuote from: jakeroot on October 19, 2017, 12:48:19 AM
I have seen quite a few dual FYA displays elsewhere in Minnesota IRL, but they all ran protected-only. Not sure what MnDOT policy is nowadays.
Isn't MnDOT's policy nowadays to instal 4 section FYA displays for ALL left turn signal movements, even if the signal is intended to only be operated in Protected mode?
That's what I was told in the past, but that seemed like such an odd move, I've remained sceptical.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: MCRoads on October 25, 2017, 10:07:06 AM
Post by: MCRoads on October 25, 2017, 10:07:06 AM
Quote from: jakeroot on June 13, 2017, 04:21:09 PM
Just decided the check the poll.
Surprisingly close.
The real surprise? 15% of those polled, picked "cat".
wtf
LOL, i did! Honestly, i did just for fun! :bigass:
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Bitmapped on October 25, 2017, 10:31:36 AM
Post by: Bitmapped on October 25, 2017, 10:31:36 AM
I haven't seen any examples of dual left PPLT in West Virginia, but but I like the concept and think it would work fine as long as the dual left is clearly signed and there are dashed lines through the intersection so it's super obvious what's going on.
i can think of several intersections near me where, most of the day, single lane PPLT works fine but at peak hours, dual lefts are really needed to handle the load. If you went protected-only for the dual lefts, it would increase delay for most of the day to benefit those couple hours when the dual lefts are really needed. PPLT dual left would seem to offer the best of both worlds with additional capacity and the the reduced delay that PPLT can permit.
i can think of several intersections near me where, most of the day, single lane PPLT works fine but at peak hours, dual lefts are really needed to handle the load. If you went protected-only for the dual lefts, it would increase delay for most of the day to benefit those couple hours when the dual lefts are really needed. PPLT dual left would seem to offer the best of both worlds with additional capacity and the the reduced delay that PPLT can permit.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on October 25, 2017, 11:55:28 AM
Post by: jakeroot on October 25, 2017, 11:55:28 AM
Quote from: Bitmapped on October 25, 2017, 10:31:36 AM
i can think of several intersections near me where, most of the day, single lane PPLT works fine but at peak hours, dual lefts are really needed to handle the load. If you went protected-only for the dual lefts, it would increase delay for most of the day to benefit those couple hours when the dual lefts are really needed. PPLT dual left would seem to offer the best of both worlds with additional capacity and the the reduced delay that PPLT can permit.
At least one city near me has started to face this dilemma. All single-lane left turns have been converted to FYA, and while that has dramatically improved traffic, some of them don't have enough storage space. So, several major intersections have double lefts, but they're all protected-only, as is standard practice. They want to use FYAs for at least some of these double lefts, but are currently holding back until they are absolutely certain that it's the right decision.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: doorknob60 on October 25, 2017, 05:57:02 PM
Post by: doorknob60 on October 25, 2017, 05:57:02 PM
Quote from: jakeroot on October 25, 2017, 11:55:28 AMQuote from: Bitmapped on October 25, 2017, 10:31:36 AM
i can think of several intersections near me where, most of the day, single lane PPLT works fine but at peak hours, dual lefts are really needed to handle the load. If you went protected-only for the dual lefts, it would increase delay for most of the day to benefit those couple hours when the dual lefts are really needed. PPLT dual left would seem to offer the best of both worlds with additional capacity and the the reduced delay that PPLT can permit.
At least one city near me has started to face this dilemma. All single-lane left turns have been converted to FYA, and while that has dramatically improved traffic, some of them don't have enough storage space. So, several major intersections have double lefts, but they're all protected-only, as is standard practice. They want to use FYAs for at least some of these double lefts, but are currently holding back until they are absolutely certain that it's the right decision.
Boise (well, I think in this case it was ITD, probably in collaboration with ACHD) recently converted a dual left turn setup to single left with FYA. It's at Broadway and Beacon. Well actually, one side of the intersection was dual left, and the other side was single left, protected only (because the opposing left turn lane blocked your view). And there are a lot of intersections in Boise and Meridian where there is room for two turn lanes, but only one of them is in use with a painted barrier where the second lane would be, with FYA. Unsure if any of those used to be protected only dual lefts.
Dual lefts are incredibly common here, and you see FYAs at almost every single left turn lane, so it will be interesting to see what happens with some of the intersections around here as traffic counts change. Dual permissive lefts could be very nice here if they ever allow them. Broadway/Beacon definitely didn't need the dual lefts, at least not now that the new Broadway Bridge opened (though this particular setup possibly pre-dates the west Parkcenter bridge which would make sense, though I'm not too familiar with Boise road history).
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on October 25, 2017, 06:26:39 PM
Post by: jakeroot on October 25, 2017, 06:26:39 PM
Quote from: doorknob60 on October 25, 2017, 05:57:02 PMQuote from: jakeroot on October 25, 2017, 11:55:28 AMQuote from: Bitmapped on October 25, 2017, 10:31:36 AM
i can think of several intersections near me where, most of the day, single lane PPLT works fine but at peak hours, dual lefts are really needed to handle the load. If you went protected-only for the dual lefts, it would increase delay for most of the day to benefit those couple hours when the dual lefts are really needed. PPLT dual left would seem to offer the best of both worlds with additional capacity and the the reduced delay that PPLT can permit.
At least one city near me has started to face this dilemma. All single-lane left turns have been converted to FYA, and while that has dramatically improved traffic, some of them don't have enough storage space. So, several major intersections have double lefts, but they're all protected-only, as is standard practice. They want to use FYAs for at least some of these double lefts, but are currently holding back until they are absolutely certain that it's the right decision.
Boise (well, I think in this case it was ITD, probably in collaboration with ACHD) recently converted a dual left turn setup to single left with FYA. It's at Broadway and Beacon. Well actually, one side of the intersection was dual left, and the other side was single left, protected only (because the opposing left turn lane blocked your view). And there are a lot of intersections in Boise and Meridian where there is room for two turn lanes, but only one of them is in use with a painted barrier where the second lane would be, with FYA. Unsure if any of those used to be protected only dual lefts.
I'm glad to hear they didn't unnecessarily stick with the dual protected left. It's often not necessary....
Quote from: doorknob60 on October 25, 2017, 05:57:02 PM
Broadway/Beacon definitely didn't need the dual lefts, at least not now that the new Broadway Bridge opened.
California has a tendency to do something like this. They build/upgrade a new road, and they automatically build dual left turn lanes at all the major intersections and, of course, set them to protected-only. There are more than a few situations where double left turn lanes are desirable, but a lot of the ones I see don't need two lanes at all. What they need is a single-lane setup with protected/permissive phasing. Depending on the time of day, they can push more cars through an intersection than a double left. The problem, of course, is what to do at peak hours, when you might need more storage capacity, or there's too many oncoming cars for the permissive phase to be of any use. You could keep it as a single left, and switch to protected-only phasing, but that's effectively capping the throughput of the lane (permissive phasing at all times allows a variable amount of cars through during each phase, since some phases have more gaps than others, and sometimes, you'll get three or four cars turning after the red light (something that should always be practiced IMO)). You could also build a dual left with permanently protected phasing, but it will only be helpful during peak hours (though backups can still occur), and during off-peak hours, it's just annoying because you have to wait for a green arrow. The dual-permissive FYA is the result of this conundrum.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: roadfro on October 26, 2017, 08:52:47 AM
Post by: roadfro on October 26, 2017, 08:52:47 AM
For those agencies that are hesitant about a dual permissive left, but need the capacity of dual lefts in the peak hour: I wonder if there's a way you could program a signal and adequately sign/stripe the intersection so that the second turn lane is used only in the peak hour during protected-only mode, but leave one lane for permitted lefts during non-peak hours...
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on October 26, 2017, 02:27:33 PM
Post by: jakeroot on October 26, 2017, 02:27:33 PM
Quote from: roadfro on October 26, 2017, 08:52:47 AM
For those agencies that are hesitant about a dual permissive left, but need the capacity of dual lefts in the peak hour: I wonder if there's a way you could program a signal and adequately sign/stripe the intersection so that the second turn lane is used only in the peak hour during protected-only mode, but leave one lane for permitted lefts during non-peak hours...
There was a document (https://goo.gl/YFi5e7) produced by VDOT several years ago (I've posted the document before -- read the ITE stories on the bottom if you haven't already), where agencies wrote in about their FYA experiences. One of the ITE (Institute of Transport Engineers) members from Wilmington, NC wrote in, suggesting something like that:
Quote
For duals, we have seen permitted operation and have just discovered the NCDOT is experimenting with them. We have one location out of 212 that we think may lend itself to this operation. Like the previous point, rarely do we need duals in the overnight hours. I think the technology will evolve that we can vary the duals by TOD. Therefore the outside turn lane would run with a standard three section head and the inside with a 4 section FYA. During times when the duals are needed, the FYA would be extinguished and full protection afforded. Later, when appropriate the FYA activated and the outside lane closed with a blankout sign. The three section(s) would stay red and the blankout sign would flash if the detector for that lane became active.
(I love the "one...out of 212" comment -- that's really it?!?)
Sounds rather complicated to me. As you might imagine, I'd rather just see FYA displays used for both lanes, with the roadway properly designed to accommodate both lanes yielding.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: mrsman on October 27, 2017, 11:36:04 AM
Post by: mrsman on October 27, 2017, 11:36:04 AM
Quote from: jakeroot on October 26, 2017, 02:27:33 PM
Sounds rather complicated to me. As you might imagine, I'd rather just see FYA displays used for both lanes, with the roadway properly designed to accommodate both lanes yielding.
You are right. But I think many states are too afraid to allow dual permissive turning. In many places, it is quite common to close lanes with a red X over the lane for maintenance and similar purposes. To save people time, it is well worth while.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on October 27, 2017, 02:12:14 PM
Post by: jakeroot on October 27, 2017, 02:12:14 PM
Quote from: mrsman on October 27, 2017, 11:36:04 AMQuote from: jakeroot on October 26, 2017, 02:27:33 PM
Sounds rather complicated to me. As you might imagine, I'd rather just see FYA displays used for both lanes, with the roadway properly designed to accommodate both lanes yielding.
You are right. But I think many states are too afraid to allow dual permissive turning. In many places, it is quite common to close lanes with a red X over the lane for maintenance and similar purposes. To save people time, it is well worth while.
The stickler in me would rather just see it done properly. Obviously, at least some of these places are considering dual permissive turns. Otherwise, they wouldn't be considering the whole "close a lane off during off-hours" solution (although that's a result of being concerned with the concept). If they just designed the left turn lanes correctly, they wouldn't need to bother with anything special.
A better idea, at least compared to the lane-closing concept, might be to just only have an FYA display over one of the lanes. Kind of like banning RTOR from the left lane of a dual right turn lane.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: roadfro on October 28, 2017, 10:17:34 AM
Post by: roadfro on October 28, 2017, 10:17:34 AM
Quote from: jakeroot on October 27, 2017, 02:12:14 PM
The stickler in me would rather just see it done properly. Obviously, at least some of these places are considering dual permissive turns. Otherwise, they wouldn't be considering the whole "close a lane off during off-hours" solution (although that's a result of being concerned with the concept). If they just designed the left turn lanes correctly, they wouldn't need to bother with anything special.
A better idea, at least compared to the lane-closing concept, might be to just only have an FYA display over one of the lanes. Kind of like banning RTOR from the left lane of a dual right turn lane.
If you just had an FYA over one lane and a standard arrow setup over the other, I think you'd get lane imbalance issues. Or you'd get compliance issues in the second lane. A blank out sign to indicate the #2 lane signal is not in use during off-peak times would help inform the driver and deal with driver expectancy.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Revive 755 on October 28, 2017, 10:54:16 AM
Post by: Revive 755 on October 28, 2017, 10:54:16 AM
Quote from: roadfro on October 28, 2017, 10:17:34 AMQuote from: jakeroot on October 27, 2017, 02:12:14 PM
The stickler in me would rather just see it done properly. Obviously, at least some of these places are considering dual permissive turns. Otherwise, they wouldn't be considering the whole "close a lane off during off-hours" solution (although that's a result of being concerned with the concept). If they just designed the left turn lanes correctly, they wouldn't need to bother with anything special.
A better idea, at least compared to the lane-closing concept, might be to just only have an FYA display over one of the lanes. Kind of like banning RTOR from the left lane of a dual right turn lane.
If you just had an FYA over one lane and a standard arrow setup over the other, I think you'd get lane imbalance issues. Or you'd get compliance issues in the second lane.
I see the imbalance/compliance issues in Chicagoland a lot with dual rights where the inner lane is NTOR. There's also the issue of someone using the turn lane that allows turns on red turning into the correct lane and then quickly switching to the lane the NTOR lane would have turned into, possibly cutting off the driver who used the NTOR lane and waited for the light to cycle.
Using a FYA head for the permissive-prot left turn lane and a protected only head for the other left turn lane would make it difficult to provide secondary/backup/redundant signal heads for the left turns. IMHO it would be better to use lane control signals to close one of the left turn lanes or go to a modified version of Wisconsin's slotted left turn lanes (example on WI 50 near Kenosha) (https://www.google.com/maps/@42.5667493,-87.9149731,95m/data=!3m1!1e3?hl=en) with a raised median between the two left turn lanes and gate off the closed turn lane during non-peak hours.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on October 28, 2017, 11:17:55 AM
Post by: jakeroot on October 28, 2017, 11:17:55 AM
Quote from: roadfro on October 28, 2017, 10:17:34 AMQuote from: jakeroot on October 27, 2017, 02:12:14 PM
The stickler in me would rather just see it done properly. Obviously, at least some of these places are considering dual permissive turns. Otherwise, they wouldn't be considering the whole "close a lane off during off-hours" solution (although that's a result of being concerned with the concept). If they just designed the left turn lanes correctly, they wouldn't need to bother with anything special.
A better idea, at least compared to the lane-closing concept, might be to just only have an FYA display over one of the lanes. Kind of like banning RTOR from the left lane of a dual right turn lane.
If you just had an FYA over one lane and a standard arrow setup over the other, I think you'd get lane imbalance issues. Or you'd get compliance issues in the second lane. A blank out sign to indicate the #2 lane signal is not in use during off-peak times would help inform the driver and deal with driver expectancy.
I think you'd have the same amount of obedience issues with blank-out signs and red arrows. Neither seems like a particularly good concept. Either way, it confuses drivers who expect both lanes to work the same (instead of having one lane closed sometimes, or having only one lane allowed to yield). I think you'd probably agree that having both lanes phased the same (pro or pro/per) would be far superior.
As far as lane balance, that's an issue IRL. Virginia never allows RTOR from the left lane of a double right turn. Everyone lines up in the lane that permits RTOR.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on December 16, 2017, 05:08:31 AM
Post by: jakeroot on December 16, 2017, 05:08:31 AM
You guys probably think I've run out of things to post in this thread...wrong! :-P
Kennewick, Washington recently activated two new double-left flashing yellow arrows. Both at the same intersection: Hildebrand Blvd @ Plaza Way, just northeast of the I-82/US-395 trumpet. One of the signals is for the SB to EB left turn (likely due to the short queue area), and the other is for the WB to SB left turn (implemented because Kennewick just likes this sort of thing; they've been using double permissive lefts since 2004).
https://goo.gl/GXbLQ4
(https://i.imgur.com/NVCHt1Y.png)
(https://i.imgur.com/8c0Xcj5.png)
Kennewick, Washington recently activated two new double-left flashing yellow arrows. Both at the same intersection: Hildebrand Blvd @ Plaza Way, just northeast of the I-82/US-395 trumpet. One of the signals is for the SB to EB left turn (likely due to the short queue area), and the other is for the WB to SB left turn (implemented because Kennewick just likes this sort of thing; they've been using double permissive lefts since 2004).
https://goo.gl/GXbLQ4
(https://i.imgur.com/NVCHt1Y.png)
(https://i.imgur.com/8c0Xcj5.png)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: MNHighwayMan on December 16, 2017, 07:54:56 AM
Post by: MNHighwayMan on December 16, 2017, 07:54:56 AM
Quote from: Revive 755 on September 29, 2017, 10:01:11 PM
Found a protected-permissive dual left in Ankeny, Iowa for US 69/Ankeny Boulvard at 1st Street that uses two five-section towers: Streetview (https://www.google.com/maps/@41.7319437,-93.6002988,3a,53.1y,241.2h,87.79t/data=!3m6!1e1!3m4!1sW48hhj3RFDsCQQd91BG8OQ!2e0!7i13312!8i6656?hl=en)
The Des Moines newspaper though indicates this will be changed to a single left. http://www.desmoinesregister.com/story/news/local/ankeny/2017/09/29/ankeny-boulevard-and-1st-street-improvements-coming-2020/718133001/ (http://www.desmoinesregister.com/story/news/local/ankeny/2017/09/29/ankeny-boulevard-and-1st-street-improvements-coming-2020/718133001/)
Since jakeroot resurrected this thread from its two-month hibernation, here's a picture (which this thread inspired me to go get) of that dual-left setup in Ankeny that I took on Oct. 11. I would've posted a picture in the permissive phase, but apparently I didn't think to take one.
(https://i.imgur.com/JjPUsjE.jpg)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: Roadwarriors79 on February 12, 2018, 03:03:24 AM
Post by: Roadwarriors79 on February 12, 2018, 03:03:24 AM
In Chandler AZ, there are a few intersections with dual left turns where FYA signals have been installed. In Peoria AZ, I know of ONE intersection with dual left turns that uses FYA signals. The other intersections look like they were restriped to have a single left turn lane and new FYA installs. The other dual left turns are protected left signals.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: doorknob60 on March 08, 2018, 03:01:52 PM
Post by: doorknob60 on March 08, 2018, 03:01:52 PM
ITD just posted this about the first dual permissive left just installed in Idaho: http://itd.idaho.gov/news/itd-tests-new-traffic-infrastructure-in-cda/
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fitd.idaho.gov%2Fwp-content%2Fuploads%2F2018%2F03%2FDFYA3-900x400.png&hash=75e5528d1e53039a17c2d44f6d4998239dd2b801)
Side note, I never knew there was one in Kennewick. Used to live near there, but that was over a decade ago now :O
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fitd.idaho.gov%2Fwp-content%2Fuploads%2F2018%2F03%2FDFYA3-900x400.png&hash=75e5528d1e53039a17c2d44f6d4998239dd2b801)
Quote
In an effort to improve mobility at a major intersection in Coeur d'Alene, ITD's North Idaho (District 1) traffic engineers activated a new signal function in December.
The signal at the Fourth Street on-ramp to Interstate 90 heading west now allows two lanes of traffic to turn left after yielding to oncoming vehicles and pedestrians. While local drivers may be familiar with how flashing yellow arrows function, this is the first site in the district–and the state–to use double flashing yellow arrows.
"This is one of the busiest intersections in the Coeur d'Alene metropolitan area, which is the fastest-growing area in the state," ITD District 1 Traffic Engineer Ben Ward said. "We're open to finding new ways to move more cars through."
The idea began with former traffic engineer Ryan Hawkins, who first saw a signal like this while passing through Kennewick, Washington, nearly three years ago.
"Technology like this can be leveraged to maintain mobility in congested corridors," Hawkins said. "We can't build our way out of this congestion, so we have to identify other options to optimize the infrastructure we currently have."
After his trip through Kennewick, Hawkins talked to signal manufacturers and brought the idea back to the department's working groups tasked with identifying innovative solutions. Access to westbound I-90 from Fourth Street became an informal test site for the rest of the state.
Ward said he was initially concerned the public would be confused when approaching this intersection, but since activating the new function three months ago, there have been no issues.
"We haven't received any concerned calls, and there haven't been any crashes out there because of the signal," Ward said. "The signal is moving traffic better."
Since there are not many signals like this in the region, Ward plans to monitor the site to determine if this technology should be implemented at other busy intersections, such as Prairie Avenue and ID-41 in an upcoming project.
"Right now, we are still watching the signal to make sure it is safe before we start installing more," Ward said. "So far, so good."
Side note, I never knew there was one in Kennewick. Used to live near there, but that was over a decade ago now :O
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: US 89 on March 08, 2018, 06:00:57 PM
Post by: US 89 on March 08, 2018, 06:00:57 PM
There are no dual permissive lefts, but there are many dual permissive right turns in Utah. If there's a right turn filter signal, it's almost always a doghouse.
Here's one in Lehi, UT with double doghouses (https://www.google.com/maps/@40.4316885,-111.8809601,3a,30.7y,187.69h,95.94t/data=!3m6!1e1!3m4!1sY_8gCCYzAmmLggF3QmwONQ!2e0!7i13312!8i6656), which I don't think I've seen anywhere else in UT.
Here's one in Lehi, UT with double doghouses (https://www.google.com/maps/@40.4316885,-111.8809601,3a,30.7y,187.69h,95.94t/data=!3m6!1e1!3m4!1sY_8gCCYzAmmLggF3QmwONQ!2e0!7i13312!8i6656), which I don't think I've seen anywhere else in UT.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on March 08, 2018, 07:08:06 PM
Post by: jakeroot on March 08, 2018, 07:08:06 PM
Quote from: doorknob60 on March 08, 2018, 03:01:52 PM
ITD just posted this about the first dual permissive left just installed in Idaho: http://itd.idaho.gov/news/itd-tests-new-traffic-infrastructure-in-cda/
Nice! Freeway on ramps are the perfect place for these.
Quote from: doorknob60 on March 08, 2018, 03:01:52 PM
Side note, I never knew there was one in Kennewick. Used to live near there, but that was over a decade ago now :O
Kennewick has had a few in place since at least 2008. At the top of this page, I actually posted an image of a recent install in Kennewick. It appears as though its now the standard for double left turns.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on March 18, 2018, 11:47:02 PM
Post by: jakeroot on March 18, 2018, 11:47:02 PM
Not sure how common these are in Chicago, but I found one near the north end of Lake Shore Drive involving an option lane:
https://goo.gl/vj8bsC
(https://i.imgur.com/8LFjV8N.png)
https://goo.gl/vj8bsC
(https://i.imgur.com/8LFjV8N.png)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: US 89 on March 18, 2018, 11:53:02 PM
Post by: US 89 on March 18, 2018, 11:53:02 PM
Quote from: jakeroot on March 18, 2018, 11:47:02 PM
Not sure how common these are in Chicago, but I found one near the north end of Lake Shore Drive involving an option lane:
https://goo.gl/vj8bsC
(https://i.imgur.com/8LFjV8N.png)
If that were in Utah, it would almost certainly be split phased.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on March 19, 2018, 12:00:54 AM
Post by: jakeroot on March 19, 2018, 12:00:54 AM
In South Africa, the "clearance" interval is typically two seconds. I think it may need to be a bit longer at this junction:
M17/M9 junction, Ottery, Cape Town (https://goo.gl/P7hjpc)
By my own estimations, the bottom-to-right storage box can accommodate about 12 cars at a time. Judging by street view (elsewhere, as this junction was just opened), South Africans lodge themselves as far forward as they possibly can (past the stop line) when waiting to turn right, so it's not unlikely that 12 would actually be out there waiting to turn. At this (https://goo.gl/dxaCsq) slightly more normal double permissive right, there's eight cars waiting past the stop line.
(https://i.imgur.com/WAwa49z.png)
M17/M9 junction, Ottery, Cape Town (https://goo.gl/P7hjpc)
By my own estimations, the bottom-to-right storage box can accommodate about 12 cars at a time. Judging by street view (elsewhere, as this junction was just opened), South Africans lodge themselves as far forward as they possibly can (past the stop line) when waiting to turn right, so it's not unlikely that 12 would actually be out there waiting to turn. At this (https://goo.gl/dxaCsq) slightly more normal double permissive right, there's eight cars waiting past the stop line.
(https://i.imgur.com/WAwa49z.png)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on March 19, 2018, 12:12:52 AM
Post by: jakeroot on March 19, 2018, 12:12:52 AM
Quote from: roadguy2 on March 18, 2018, 11:53:02 PMQuote from: jakeroot on March 18, 2018, 11:47:02 PM
Not sure how common these are in Chicago, but I found one near the north end of Lake Shore Drive involving an option lane:
https://goo.gl/vj8bsC
(https://i.imgur.com/8LFjV8N.png)
If that were in Utah, it would almost certainly be split phased.
As I think it normally would be in Illinois and most other areas (except a few cities such as Tucson or areas around Denver). Seattle has a double permissive left turn with an option lane just like this image (except with one more through lane), which I posted an image of on the first page (the OP, actually).
Title: Re: Double left turns with permissive phasing
Post by: MCRoads on April 06, 2018, 12:15:14 PM
Post by: MCRoads on April 06, 2018, 12:15:14 PM
Found one!!!
Academy and Carefree in Colorado Springs!!!
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FyeD1X4J.jpg&hash=d1b3a156d8ba61d5acbae0f4329eea862cce52ee)
Academy and Carefree in Colorado Springs!!!
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FyeD1X4J.jpg&hash=d1b3a156d8ba61d5acbae0f4329eea862cce52ee)
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 06, 2018, 09:04:54 PM
Post by: jakeroot on April 06, 2018, 09:04:54 PM
Quote from: MCRoads on April 06, 2018, 12:15:14 PM
Found one!!!
Academy and Carefree in Colorado Springs!!!
http://i.imgur.com/yeD1X4J.jpg
No surprise really. Colorado has used dual permissive phasing all across the state for quite a while now. Here's three more examples from Colorado Springs (that I knew of previously -- these are in addition to literally hundred+ other examples in the metro Denver area). Click the photos for Street View. The double-doghouse was the standard setup (usually with a tower on the left-most mast arm), but the state has basically switched over to flashing yellow arrows at this point.
(https://i.imgur.com/yMo2psi.png) (https://goo.gl/scSZai)
(https://i.imgur.com/itumvrQ.png) (https://goo.gl/3dpTuV)
(https://i.imgur.com/9a61Rkm.png) (https://goo.gl/Cs5sp9)
Title: Re: Double left turns with permissive phasing
Post by: Revive 755 on April 07, 2018, 11:06:43 AM
Post by: Revive 755 on April 07, 2018, 11:06:43 AM
Not sure WB 30th Street at South Expressway and the EB I-80/SB I-29 ramps in Council Bluffs, Iowa, has been mentioned yet. Streetview WB (https://goo.gl/maps/7Xu6Jx2PwNF2). Also the first time I believe I have seen both doghouses and a 5-section tower on the same mast arm (for EB).
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 07, 2018, 02:25:35 PM
Post by: jakeroot on April 07, 2018, 02:25:35 PM
Quote from: Revive 755 on April 07, 2018, 11:06:43 AM
Not sure WB 30th Street at South Expressway and the EB I-80/SB I-29 ramps in Council Bluffs, Iowa, has been mentioned yet. Streetview WB (https://goo.gl/maps/7Xu6Jx2PwNF2). Also the first time I believe I have seen both doghouses and a 5-section tower on the same mast arm (for EB).
Wait, which approach has the double permissive left? I see a double doghouse, but it looks like it's for when a train is approaching, and the off-ramp's center lane turns into a right turn lane (hence the double 5-section signals with right-facing arrows.
Doghouse and tower signals on the same mast arm are indeed quite rare. I've only seen it once before in Auburn, WA, and it's since been removed.
Title: Re: Double left turns with permissive phasing
Post by: MNHighwayMan on April 07, 2018, 06:52:24 PM
Post by: MNHighwayMan on April 07, 2018, 06:52:24 PM
Maybe/maybe not there, but there is definitely a pair of them in West Des Moines at the reconstructed Grand Avenue interchange with I-35. This is the one for EB Grand to turn onto NB I-35:
(https://i.imgur.com/Vji0x0v.jpg)
(https://i.imgur.com/nLiysXW.jpg)
(https://i.imgur.com/Vji0x0v.jpg)
(https://i.imgur.com/nLiysXW.jpg)
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 07, 2018, 08:55:09 PM
Post by: jakeroot on April 07, 2018, 08:55:09 PM
Quote from: MNHighwayMan on April 07, 2018, 06:52:24 PM
Maybe/maybe not there, but there is definitely a pair of them in West Des Moines at the reconstructed Grand Avenue interchange with I-35. This is the one for EB Grand to turn onto NB I-35:
Satellite imagery from October shows only one left turn lane from Grand Ave to both north and south 35W. I'm guessing things have been modified since then? There's clearly room for another turn lane.
Title: Re: Double left turns with permissive phasing
Post by: MNHighwayMan on April 07, 2018, 08:58:35 PM
Post by: MNHighwayMan on April 07, 2018, 08:58:35 PM
Yep. Those pictures are from January 30, 2018. I'm not sure, since I don't go over that way too often, but I think the work was done not long after that aerial imagery was taken.
Title: Re: Double left turns with permissive phasing
Post by: Revive 755 on April 08, 2018, 07:56:18 PM
Post by: Revive 755 on April 08, 2018, 07:56:18 PM
Quote from: jakeroot on April 07, 2018, 02:25:35 PMQuote from: Revive 755 on April 07, 2018, 11:06:43 AM
Not sure WB 30th Street at South Expressway and the EB I-80/SB I-29 ramps in Council Bluffs, Iowa, has been mentioned yet. Streetview WB (https://goo.gl/maps/7Xu6Jx2PwNF2). Also the first time I believe I have seen both doghouses and a 5-section tower on the same mast arm (for EB).
Wait, which approach has the double permissive left? I see a double doghouse, but it looks like it's for when a train is approaching, and the off-ramp's center lane turns into a right turn lane (hence the double 5-section signals with right-facing arrows.
I thought WB 30th Street (the east leg did), but it appears I misinterpreted the signing on the mast arm - the middle sign should be an R3-5 with only a straight ahead arrow. Guess I've been corrupted lately by seeing too many option lane signs with 'only' on them and also seeing many intersections having signal heads not match intended lane usage.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 09, 2018, 07:46:43 PM
Post by: jakeroot on April 09, 2018, 07:46:43 PM
Quote from: Revive 755 on April 08, 2018, 07:56:18 PMQuote from: jakeroot on April 07, 2018, 02:25:35 PMQuote from: Revive 755 on April 07, 2018, 11:06:43 AM
Not sure WB 30th Street at South Expressway and the EB I-80/SB I-29 ramps in Council Bluffs, Iowa, has been mentioned yet. Streetview WB (https://goo.gl/maps/7Xu6Jx2PwNF2). Also the first time I believe I have seen both doghouses and a 5-section tower on the same mast arm (for EB).
Wait, which approach has the double permissive left? I see a double doghouse, but it looks like it's for when a train is approaching, and the off-ramp's center lane turns into a right turn lane (hence the double 5-section signals with right-facing arrows.
I thought WB 30th Street (the east leg did), but it appears I misinterpreted the signing on the mast arm - the middle sign should be an R3-5 with only a straight ahead arrow. Guess I've been corrupted lately by seeing too many option lane signs with 'only' on them and also seeing many intersections having signal heads not match intended lane usage.
I noticed that signing irregularity when you first posted the intersection (and I spent several minutes scanning the ground to confirm that it was accurate, which I was not able to). Indeed quite misleading. Typically you don't see lane use signs and specific lane control signs on the same arm. Totally understandable misinterpretation.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 09, 2018, 01:55:54 AM
Post by: jakeroot on July 09, 2018, 01:55:54 AM
Edmonton, Alberta used to have a bunch of double permissive left turns, but many have disappeared. They have actually become quite hard to find. Far cry from the days of the city actually being known by engineers outside the city just for these. Now, there seems to only be a handful left.
One that I went through a couple of times when I was last there has been changed to protected-only. Odd that they didn't try to improve safety by implementing a short protected phase, but it's irrelevant now. What I did find funny was, that, after reviewing Street View footage, I noticed that the original left turn, circa 2009, was a single permissive-only left turn. In 2009, Stony Plain Road was widened significantly, and double left turns were included for the east and west approaches. Despite the additional left turn lane for each approach, permissive-only phasing was kept. The vast majority of double permissive turns, regardless of location (or country), seem to have some sort of protected phase (otherwise, a protected-permissive single lane approach would have probably worked well too). Seattle has a few of these, but for the most part, it's pretty damn unusual. Especially unusual in this case because the road was so new.
Typically, when a city widens a road or adds an additional left turn lane, it's due to either current or future volume. Either way, you typically see the phasing changed to either protected-permissive or protected only. But, I guess the traffic counts were still so low, they kept the permissive only phasing for these left turns.
2012 GSV, before protected-only phasing: https://goo.gl/2iMzti
2009...
(https://i.imgur.com/xVi7qGK.png)
2010/2011 (until ~2016)...
(https://i.imgur.com/hGQmUqR.png)
One that I went through a couple of times when I was last there has been changed to protected-only. Odd that they didn't try to improve safety by implementing a short protected phase, but it's irrelevant now. What I did find funny was, that, after reviewing Street View footage, I noticed that the original left turn, circa 2009, was a single permissive-only left turn. In 2009, Stony Plain Road was widened significantly, and double left turns were included for the east and west approaches. Despite the additional left turn lane for each approach, permissive-only phasing was kept. The vast majority of double permissive turns, regardless of location (or country), seem to have some sort of protected phase (otherwise, a protected-permissive single lane approach would have probably worked well too). Seattle has a few of these, but for the most part, it's pretty damn unusual. Especially unusual in this case because the road was so new.
Typically, when a city widens a road or adds an additional left turn lane, it's due to either current or future volume. Either way, you typically see the phasing changed to either protected-permissive or protected only. But, I guess the traffic counts were still so low, they kept the permissive only phasing for these left turns.
2012 GSV, before protected-only phasing: https://goo.gl/2iMzti
2009...
(https://i.imgur.com/xVi7qGK.png)
2010/2011 (until ~2016)...
(https://i.imgur.com/hGQmUqR.png)
Title: Re: Double left turns with permissive phasing
Post by: Roadwarriors79 on October 21, 2018, 12:20:37 PM
Post by: Roadwarriors79 on October 21, 2018, 12:20:37 PM
@Jakeroot, this link is for you. As of June 2018, Broadway Blvd and Aviation Hwy (AZ 210) in Tucson STILL has permissive dual left turns at this half-SPUI:
https://www.google.com/maps/@32.2210231,-110.9618543,3a,75y,244.05h,87.64t/data=!3m6!1e1!3m4!1sIQYZESMK6u1M-ZZVjMUiuA!2e0!7i13312!8i6656
https://www.google.com/maps/@32.2210231,-110.9618543,3a,75y,244.05h,87.64t/data=!3m6!1e1!3m4!1sIQYZESMK6u1M-ZZVjMUiuA!2e0!7i13312!8i6656
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on October 21, 2018, 01:12:17 PM
Post by: jakeroot on October 21, 2018, 01:12:17 PM
Quote from: Roadwarriors79 on October 21, 2018, 12:20:37 PM
@Jakeroot, this link is for you. As of June 2018, Broadway Blvd and Aviation Hwy (AZ 210) in Tucson STILL has permissive dual left turns at this half-SPUI:
https://www.google.com/maps/@32.2210231,-110.9618543,3a,75y,244.05h,87.64t/data=!3m6!1e1!3m4!1sIQYZESMK6u1M-ZZVjMUiuA!2e0!7i13312!8i6656
Great to see. It's a good place for a permissive turn, not having any oncoming traffic.
Title: Re: Double left turns with permissive phasing
Post by: Roadwarriors79 on October 21, 2018, 02:59:41 PM
Post by: Roadwarriors79 on October 21, 2018, 02:59:41 PM
Quote from: jakeroot on October 21, 2018, 01:12:17 PMQuote from: Roadwarriors79 on October 21, 2018, 12:20:37 PM
@Jakeroot, this link is for you. As of June 2018, Broadway Blvd and Aviation Hwy (AZ 210) in Tucson STILL has permissive dual left turns at this half-SPUI:
https://www.google.com/maps/@32.2210231,-110.9618543,3a,75y,244.05h,87.64t/data=!3m6!1e1!3m4!1sIQYZESMK6u1M-ZZVjMUiuA!2e0!7i13312!8i6656
Great to see. It's a good place for a permissive turn, not having any oncoming traffic.
What about the traffic going EB on Broadway? It's weird to me because every other SPUI or half-SPUI I have seen has had protected left signals in all directions. Even in Tucson.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on October 21, 2018, 03:17:10 PM
Post by: jakeroot on October 21, 2018, 03:17:10 PM
Quote from: Roadwarriors79 on October 21, 2018, 02:59:41 PMQuote from: jakeroot on October 21, 2018, 01:12:17 PMQuote from: Roadwarriors79 on October 21, 2018, 12:20:37 PM
@Jakeroot, this link is for you. As of June 2018, Broadway Blvd and Aviation Hwy (AZ 210) in Tucson STILL has permissive dual left turns at this half-SPUI:
https://www.google.com/maps/@32.2210231,-110.9618543,3a,75y,244.05h,87.64t/data=!3m6!1e1!3m4!1sIQYZESMK6u1M-ZZVjMUiuA!2e0!7i13312!8i6656
Great to see. It's a good place for a permissive turn, not having any oncoming traffic.
What about the traffic going EB on Broadway? It's weird to me because every other SPUI or half-SPUI I have seen has had protected left signals in all directions. Even in Tucson.
When I said oncoming traffic, I meant no oncoming *left turn. My bad. Visibility is good for turning traffic so I don't feel there is too much of an issue. Most SPUIs use protected phasing because the distance between the stop line and exit leg is so great, you'd need like a 7 second all red phase to clear traffic. But since lagging turns are used here, that's not a big worry.
Title: Re: Double left turns with permissive phasing
Post by: bcroadguy on November 15, 2018, 04:09:23 AM
Post by: bcroadguy on November 15, 2018, 04:09:23 AM
I found one in Richmond, BC:
https://www.google.com/maps/@49.170125,-123.1592228,3a,41y,84.91h,88.83t/data=!3m6!1e1!3m4!1szDZOotchBd0mtzZX2Ngj-w!2e0!7i16384!8i8192
https://www.google.com/maps/@49.170125,-123.1592228,3a,41y,84.91h,88.83t/data=!3m6!1e1!3m4!1szDZOotchBd0mtzZX2Ngj-w!2e0!7i16384!8i8192
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on November 15, 2018, 04:26:14 AM
Post by: jakeroot on November 15, 2018, 04:26:14 AM
Quote from: bcroadguy on November 15, 2018, 04:09:23 AM
I found one in Richmond, BC:
https://www.google.com/maps/@49.170125,-123.1592228,3a,41y,84.91h,88.83t/data=!3m6!1e1!3m4!1szDZOotchBd0mtzZX2Ngj-w!2e0!7i16384!8i8192
Oh shit, nice find! Cannot believe I didn't know about that one. Your drive through there often?
That now brings BC's total back to four. The other three are Cambie at Marine Drive, Denman at West Georgia, and Main at the Dunsmuir Viaduct. Pacific at Burrard once had it until removal a short time ago. The Richmond example, though, is the coolest so far as it doesn't involve option lanes.
Edit: you know you're in Richmond when a Lambo just casually strolls through: https://goo.gl/vPed2y
Title: Re: Double left turns with permissive phasing
Post by: bcroadguy on November 15, 2018, 04:34:03 AM
Post by: bcroadguy on November 15, 2018, 04:34:03 AM
Nah, I almost never go to Richmond. I just happened to find it on Streetview today. I knew about the Main Street one but I never noticed the double left turns at Denman & West Georgia and Cambie & Marine before. There is another one in Vancouver somewhere (with an option lane unfortunately), but I'm not sure exactly which intersection. I'll post when I find it.
Edit: Lol classic Richmond
Edit: Lol classic Richmond
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on November 15, 2018, 04:42:03 AM
Post by: jakeroot on November 15, 2018, 04:42:03 AM
Quote from: bcroadguy on November 15, 2018, 04:34:03 AM
There is another one in Vancouver somewhere (with an option lane unfortunately), but I'm not sure exactly which intersection. I'll post when I find it.
Now that you mention it, I do feel like I'm missing something from that list. Are you thinking somewhere downtown, or outside downtown but within city limits? Never would have guessed that anyone besides the City of Vancouver would have the balls to install a double permissive left, but Richmond clearly has proved me wrong. I usually focus my search for these things in urban areas, but there could be some in suburban areas too.
Title: Re: Double left turns with permissive phasing
Post by: bcroadguy on November 15, 2018, 04:51:28 AM
Post by: bcroadguy on November 15, 2018, 04:51:28 AM
Found it!
https://www.google.com/maps/@49.2578379,-123.1843362,3a,75y,84.23h,87.65t/data=!3m7!1e1!3m5!1sTZSRt0P3pMAvMerqOdhHZg!2e0!5s20170501T000000!7i13312!8i6656
https://www.google.com/maps/@49.2579849,-123.1840422,3a,23.3y,60.57h,88.97t/data=!3m7!1e1!3m5!1sm2Wy0W5ygSDGhSaDpL7YrA!2e0!5s20170501T000000!7i13312!8i6656 (Walk signal on)
Other than that Richmond example, the closest thing I've seen in the suburbs is this double left turn where you have to yield to pedestrians:https://www.google.com/maps/@49.2578379,-123.1843362,3a,75y,84.23h,87.65t/data=!3m7!1e1!3m5!1sTZSRt0P3pMAvMerqOdhHZg!2e0!5s20170501T000000!7i13312!8i6656
https://www.google.com/maps/@49.2835933,-122.8234701,3a,75y,111.39h,88.31t/data=!3m7!1e1!3m5!1sBq7KlviEkYO7cVUdphSzWA!2e0!5s20160601T000000!7i13312!8i6656
Edit: Juuuuust found this right near the example I posted. I think Richmond's probably your best bet for finding more of these:
https://www.google.com/maps/@49.1799028,-123.1538032,3a,49y,118.23h,85.93t/data=!3m7!1e1!3m5!1sbGEzFf5ezPkHiQewxF42mA!2e0!5s20160601T000000!7i13312!8i6656
https://www.google.com/maps/@49.2578379,-123.1843362,3a,75y,84.23h,87.65t/data=!3m7!1e1!3m5!1sTZSRt0P3pMAvMerqOdhHZg!2e0!5s20170501T000000!7i13312!8i6656
https://www.google.com/maps/@49.2579849,-123.1840422,3a,23.3y,60.57h,88.97t/data=!3m7!1e1!3m5!1sm2Wy0W5ygSDGhSaDpL7YrA!2e0!5s20170501T000000!7i13312!8i6656 (Walk signal on)
Other than that Richmond example, the closest thing I've seen in the suburbs is this double left turn where you have to yield to pedestrians:
https://www.google.com/maps/@49.2835933,-122.8234701,3a,75y,111.39h,88.31t/data=!3m7!1e1!3m5!1sBq7KlviEkYO7cVUdphSzWA!2e0!5s20160601T000000!7i13312!8i6656
Edit: Juuuuust found this right near the example I posted. I think Richmond's probably your best bet for finding more of these:
https://www.google.com/maps/@49.1799028,-123.1538032,3a,49y,118.23h,85.93t/data=!3m7!1e1!3m5!1sbGEzFf5ezPkHiQewxF42mA!2e0!5s20160601T000000!7i13312!8i6656
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on November 16, 2018, 01:08:00 AM
Post by: jakeroot on November 16, 2018, 01:08:00 AM
Quote from: bcroadguy on November 15, 2018, 04:51:28 AM
Found it!
https://www.google.com/maps/@49.2578379,-123.1843362,3a,75y,84.23h,87.65t/data=!3m7!1e1!3m5!1sTZSRt0P3pMAvMerqOdhHZg!2e0!5s20170501T000000!7i13312!8i6656
https://www.google.com/maps/@49.2579849,-123.1840422,3a,23.3y,60.57h,88.97t/data=!3m7!1e1!3m5!1sm2Wy0W5ygSDGhSaDpL7YrA!2e0!5s20170501T000000!7i13312!8i6656 (Walk signal on)
Oh nice! Did not know about that one, though I rarely venture out towards UBC.
Quote from: bcroadguy on November 15, 2018, 04:51:28 AM
Other than that Richmond example, the closest thing I've seen in the suburbs is this double left turn where you have to yield to pedestrians:
https://www.google.com/maps/@49.2835933,-122.8234701,3a,75y,111.39h,88.31t/data=!3m7!1e1!3m5!1sBq7KlviEkYO7cVUdphSzWA!2e0!5s20160601T000000!7i13312!8i6656
Still relatively unusual, especially for suburban cities.
Quote from: bcroadguy on November 15, 2018, 04:51:28 AM
Edit: Juuuuust found this right near the example I posted. I think Richmond's probably your best bet for finding more of these:
https://www.google.com/maps/@49.1799028,-123.1538032,3a,49y,118.23h,85.93t/data=!3m7!1e1!3m5!1sbGEzFf5ezPkHiQewxF42mA!2e0!5s20160601T000000!7i13312!8i6656
God, another one I should have known about. Apparently Richmond is pretty easy-going! Cool to see those guide lines out in the intersection to keep drivers from pulling too far forward when yielding. Normally that's not an issue but it could unintentionally block a left turner if a driver places their vehicle in the wrong place. The Denman intersection could use this (for both directions instead of just one).
I guess this is the only proper 24/7 option lane double left (with permissive phasing), as, though it permits it most of the time, the Denman/West Georgia intersection does not allow straight-ahead movements between 3 & 7pm.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on December 19, 2018, 01:40:01 AM
Post by: jakeroot on December 19, 2018, 01:40:01 AM
Christmas came early for me this year! I have been looking for a double permissive left turn in Oregon for god knows how long, and I've yet to find anything...until today. And boy, did I hit the jackpot.
In Springfield, the intersection of Martin Luther King Jr Parkway and Cardinal Way has dual permissive lefts for three of the four approaches (the fourth is a single-lane FYA):
Spin around for proof: http://bit.ly/2PLKKVu
Note the oncoming traffic sailing through the intersection, and the blank signals: http://bit.ly/2EsBh38
The lefts from Cardinal Way aren't particularly well designed, but hey, it must be the only one in Oregon, so it gets brownie points for uniqueness! I can't find a single thread of evidence online announcing this change (the phasing is new for 2018, judging by historic Street View), so it must be a test or something.
Oregon has several FYAs where a single lane approach has permissive phasing, opposite a double left with protected phasing, something I don't see too often in WA (only a couple installs that I know of), but I never would have guessed that any agency in Oregon would install dual FYAs. Sort of out-of-character, I guess.
(https://i.imgur.com/DQkt4w5.png)
In Springfield, the intersection of Martin Luther King Jr Parkway and Cardinal Way has dual permissive lefts for three of the four approaches (the fourth is a single-lane FYA):
Spin around for proof: http://bit.ly/2PLKKVu
Note the oncoming traffic sailing through the intersection, and the blank signals: http://bit.ly/2EsBh38
The lefts from Cardinal Way aren't particularly well designed, but hey, it must be the only one in Oregon, so it gets brownie points for uniqueness! I can't find a single thread of evidence online announcing this change (the phasing is new for 2018, judging by historic Street View), so it must be a test or something.
Oregon has several FYAs where a single lane approach has permissive phasing, opposite a double left with protected phasing, something I don't see too often in WA (only a couple installs that I know of), but I never would have guessed that any agency in Oregon would install dual FYAs. Sort of out-of-character, I guess.
(https://i.imgur.com/DQkt4w5.png)
Title: Re: Double left turns with permissive phasing
Post by: roadfro on December 20, 2018, 02:11:16 AM
Post by: roadfro on December 20, 2018, 02:11:16 AM
I am pretty sure I have previously asserted that Nevada does not do double permitted left turns. Today I have discovered one in the wild, and a FYA at that. It's southbound Old Virginia Road at Damonte Ranch Pkwy in south Reno. (Street view: https://goo.gl/maps/Ffnykm9Dhww) This is a part of town that I don't frequent, so am not overly familiar with the intersection dynamics–I went through tonight well after pm peak on a green arrow.
So my previous assertion was incorrect, but it's still mostly correct.
So my previous assertion was incorrect, but it's still mostly correct.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on December 23, 2018, 01:37:27 PM
Post by: Amtrakprod on December 23, 2018, 01:37:27 PM
Quote from: roadfro on December 20, 2018, 02:11:16 AMVery interesting, glad to see the FYA is set up correctly as well
I am pretty sure I have previously asserted that Nevada does not do double permitted left turns. Today I have discovered one in the wild, and a FYA at that. It's southbound Old Virginia Road at Damonte Ranch Pkwy in south Reno. (Street view: https://goo.gl/maps/Ffnykm9Dhww) This is a part of town that I don't frequent, so am not overly familiar with the intersection dynamics–I went through tonight well after pm peak on a green arrow.
So my previous assertion was incorrect, but it's still mostly correct.
iPhone
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on December 24, 2018, 02:55:07 PM
Post by: jakeroot on December 24, 2018, 02:55:07 PM
Quote from: roadfro on December 20, 2018, 02:11:16 AM
So my previous assertion was incorrect, but it's still mostly correct.
I think it's best we divide cities/states/countries into two categories: formal (2+ installs), or informal (only 1 install). Places that would qualify for the "formal" category include...
* Edmonton (AB)
* Tucson & Chandler (AZ) (latter by time-of-day only)
* Kennewick & Seattle (WA)
* Huntsville (AL)
* Vancouver (BC)
* New York City
* Colorado
* North Carolina
* Texas
* Mississippi
* Minnesota (by time-of-day?)
* South Africa
* Singapore
* Japan
* Denmark
* It should be mentioned that in Washington, Oregon, Michigan, and British Columbia, drivers may turn left onto a one-way street even when there is two or more left turn lanes, on a red light or red arrow (ID excluded since turns on red arrows are not permitted there, eliminating double lefts). In this sense, these four areas technically sanction dual permissive left turns for all on-ramps with two or more left turn lanes, though a stop is required first.
Some places with what I consider to be "informal" usage (only one install) include:
* Cupertino (http://bit.ly/2AegGww) (only briefly)
* Idaho (fairly new install in Coeur d'Alene)
* Reno
* Chicago
* Springfield (OR)
* Eau Claire (WI)
* Albuquerque
* Virginia
* Maryland
* Red Deer (AB)
* Regina (SK)
and probably a few more places that I've neglected to remember at this time. Some places like St Louis and other parts of Illinois previously had dual permissive left turns, but they've been removed. Chicago is now alone in the "informal" category, and Missouri no longer has any that I know of. Las Vegas had one, but it was removed, keeping Nevada off the formal list, and placing Reno alone in the informal list.
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on December 24, 2018, 03:13:47 PM
Post by: jakeroot on December 24, 2018, 03:13:47 PM
Quote from: Revive 755 on September 29, 2017, 10:01:11 PM
Found a protected-permissive dual left in Ankeny, Iowa for US 69/Ankeny Boulvard at 1st Street that uses two five-section towers: Streetview (https://www.google.com/maps/@41.7319437,-93.6002988,3a,53.1y,241.2h,87.79t/data=!3m6!1e1!3m4!1sW48hhj3RFDsCQQd91BG8OQ!2e0!7i13312!8i6656?hl=en)
The Des Moines newspaper though indicates this will be changed to a single left. http://www.desmoinesregister.com/story/news/local/ankeny/2017/09/29/ankeny-boulevard-and-1st-street-improvements-coming-2020/718133001/ (http://www.desmoinesregister.com/story/news/local/ankeny/2017/09/29/ankeny-boulevard-and-1st-street-improvements-coming-2020/718133001/)
Quote from: MNHighwayMan on September 29, 2017, 11:56:48 PM
Having been through that intersection a few times, yeah, it can be a bit hairy. I never understood the reason for there being two left turn lanes onto SB US-69 (Ankeny Blvd).
From this 2018/August Street View image, it appears the intersection is now operating with single left turns: http://bit.ly/2T7xoVp
(https://media.giphy.com/media/12OVdvkr6sBPDG/giphy.gif)
Title: Re: Double left turns with permissive phasing
Post by: MNHighwayMan on December 24, 2018, 04:20:45 PM
Post by: MNHighwayMan on December 24, 2018, 04:20:45 PM
That might just be temporary for minor road repair, because that linked article stated that it was going to be a couple years before they removed it. I'll have to go check it out when I'm not tipsy from Christmas. ;-)
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on December 24, 2018, 07:31:42 PM
Post by: Amtrakprod on December 24, 2018, 07:31:42 PM
Quote from: jakeroot on April 13, 2016, 02:36:51 PMI have called those "yield boxes" , I really think they are very smart and should be used in the USQuote from: Jardine on April 13, 2016, 10:51:55 AM
Even with an obvious artillery cannon blowing up cars to deter folks attempting lane changing while dual left turning, and/or the folks dual left turning onto streets with more than 2 lanes and randomly going down whatever lane they want regardless of whether or not anyone is beside them on either side and they are also attempting a similar and non-compatible random lane selection themselves (all the while mowing down pedestrians) I'd say this is an extremely poor idea for places like Sarpy County Nebraska and Rockford Illinois.
This perceived danger (vehicles changing lanes during a turn) seems to be the biggest fear among those who oppose dual permissive turns. My thought is this: are vehicles changing lanes during the permissive phase more often than during the protected phase?
Visibility really should be the argument against dual permissive turns. From studying the various dual turn lanes around the world, I've come up with two solutions to this issue:
1) Offset the dual turn lanes whenever possible. This requires slightly more ROW, but the cities that use this style seem to report fewer issues. Tucson is the best example. Note the chevrons between the left turn lanes and the through lanes. The FHWA's "Signalized Intersections: Informational Guide (https://goo.gl/31JHVM)" has a couple pages dedicated to Tucson's offset dual turns lanes, and notes a "potential issue is sight distance for the left-turning vehicles", and that "[t]he City of Tucson addresses this concern by offsetting the far lane by 1.2 to 1.5 m (4 to 5 ft) so that it has the same sight distance as a single left-turn lane" (PDF pg 338).
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FCajNWg0.png&hash=d5c73070660017d39535b614371332857809aefa)
2) Use secondary stop lines. These are almost unheard of in the US. They seem to be used more often in Europe, but more important to this conversation, South Africa has several dual permissive turn lanes with these secondary stop lines. In cities with drivers who pull pretty far forward into the intersection (cool with a single turn lane, but a little annoying with two turn lanes), this helps prevent the inside lane from being totally blind. As well, cities with more hesitant drivers will be more apt to pull forward to wait to turn, which helps with throughput. Because this secondary stop line is more of a "yield line", I'd recommend using sharks teeth, instead of the broken white lines used in South Africa:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FxRWAhR3.png&hash=0d34127525497676ed9f0e1f7f4eb40f4537d635)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F0Ce1Pwk.png&hash=634670ce4aade738b0de9b4ebbc0688e141ebcca)
iPhone
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: MNHighwayMan on December 26, 2018, 01:36:06 PM
Post by: MNHighwayMan on December 26, 2018, 01:36:06 PM
Quote from: jakeroot on December 24, 2018, 03:13:47 PM
From this 2018/August Street View image, it appears the intersection is now operating with single left turns: http://bit.ly/2T7xoVp
Quote from: MNHighwayMan on December 24, 2018, 04:20:45 PM
That might just be temporary for minor road repair, because that linked article stated that it was going to be a couple years before they removed it. I'll have to go check it out when I'm not tipsy from Christmas. ;-)
So it has been removed, I must report. All the old five-section left turn towers at the intersection were also replaced with FYAs.
(https://i.imgur.com/5ysXWTG.jpg)
Title: Re: Dual Permissive Left Turns (FYA or Doghouse)
Post by: jakeroot on December 26, 2018, 09:48:10 PM
Post by: jakeroot on December 26, 2018, 09:48:10 PM
Quote from: MNHighwayMan on December 26, 2018, 01:36:06 PMQuote from: jakeroot on December 24, 2018, 03:13:47 PM
From this 2018/August Street View image, it appears the intersection is now operating with single left turns: http://bit.ly/2T7xoVpQuote from: MNHighwayMan on December 24, 2018, 04:20:45 PM
That might just be temporary for minor road repair, because that linked article stated that it was going to be a couple years before they removed it. I'll have to go check it out when I'm not tipsy from Christmas. ;-)
So it has been removed, I must report. All the old five-section left turn towers at the intersection were also replaced with FYAs.[/img]
I feared as much. Thanks for the photos.
Is there a second flashing yellow arrow on the left side of the intersection? Just curious. I can't remember Iowa policy on auxiliary traffic lights.
Title: Re: Double left turns with permissive phasing
Post by: MNHighwayMan on December 27, 2018, 07:26:22 AM
Post by: MNHighwayMan on December 27, 2018, 07:26:22 AM
Quote from: jakeroot on December 26, 2018, 09:48:10 PM
Is there a second flashing yellow arrow on the left side of the intersection? Just curious. I can't remember Iowa policy on auxiliary traffic lights.
Nope.
(https://i.imgur.com/wZfD0JK.jpg)
Most of the time, in Iowa, there's just the overhead signal head. Rarely I'll see a left-hand arrow setup but I haven't seen any discernible reason for when and where they get applied.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on December 27, 2018, 07:49:53 AM
Post by: Amtrakprod on December 27, 2018, 07:49:53 AM
Found one in downtown Denver CO, https://www.google.com/maps/@39.7523209,-104.9966211,3a,75y,280.1h,85.65t/data=!3m6!1e1!3m4!1sOs2EZJJ9_AMXu5hzfmihJA!2e0!7i16384!8i8192
https://www.youtube.com/watch?v=Ag_cdwCVpns
https://www.youtube.com/watch?v=Ag_cdwCVpns
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on December 27, 2018, 10:46:00 PM
Post by: jakeroot on December 27, 2018, 10:46:00 PM
^^
CO probably has the most of any state. There are probably some jurisdictions that don't permit them and/or have not yet had a reason to use one, but they are all over the state in general.
CO probably has the most of any state. There are probably some jurisdictions that don't permit them and/or have not yet had a reason to use one, but they are all over the state in general.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 08, 2019, 04:46:00 AM
Post by: jakeroot on January 08, 2019, 04:46:00 AM
Quote from: bcroadguy on November 15, 2018, 04:09:23 AM
I found one in Richmond, BC:
Found yet another in Richmond. Southbound Aviation at Grant McConachie Way.
http://bit.ly/2GXQFHK -- << street view shot from 2015
I think the intersection was formerly a single-lane left, but was changed to a dual left, though tire marks suggest it's always been a dual left turn (with an option lane).
Any idea if this still operates with permissive phasing? I'd check myself but have a swamped schedule down here in Seattle. No free days for a while.
Title: Re: Double left turns with permissive phasing
Post by: roadfro on January 08, 2019, 09:47:49 AM
Post by: roadfro on January 08, 2019, 09:47:49 AM
Quote from: jakeroot on January 08, 2019, 04:46:00 AM
Found yet another in Richmond. Southbound Aviation at Grant McConachie Way.
http://bit.ly/2GXQFHK -- << street view shot from 2015
I think the intersection was formerly a single-lane left, but was changed to a dual left, though tire marks suggest it's always been a dual left turn (with an option lane).
Any idea if this still operates with permissive phasing? I'd check myself but have a swamped schedule down here in Seattle. No free days for a while.
This street view from August 2018 (https://goo.gl/maps/yGV8DoHSoF12) seems to suggest it's operating in split phase.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 08, 2019, 11:25:02 AM
Post by: jakeroot on January 08, 2019, 11:25:02 AM
Quote from: roadfro on January 08, 2019, 09:47:49 AMQuote from: jakeroot on January 08, 2019, 04:46:00 AM
Found yet another in Richmond. Southbound Aviation at Grant McConachie Way.
http://bit.ly/2GXQFHK -- << street view shot from 2015
I think the intersection was formerly a single-lane left, but was changed to a dual left, though tire marks suggest it's always been a dual left turn (with an option lane).
Any idea if this still operates with permissive phasing? I'd check myself but have a swamped schedule down here in Seattle. No free days for a while.
This street view from August 2018 (https://goo.gl/maps/yGV8DoHSoF12) seems to suggest it's operating in split phase.
It should be noted that Canada uses flashing green arrows during the protected phase at most lights. At least the ones in BC operate at 2 flashes per second, so they are not always picked up on camera. Since something like 90% of traffic lights in Vancouver operate with permissive phasing (very high understanding of yielding on green), something tells me that drivers in the street view images would not continue turning across traffic without a green arrow. I'm guessing we just can't see it.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on January 08, 2019, 03:09:45 PM
Post by: Amtrakprod on January 08, 2019, 03:09:45 PM
Quote from: jakeroot on January 08, 2019, 11:25:02 AMIf you go back a few paces, the green arrow is shown: https://www.google.com/maps/@49.1931255,-123.1668942,3a,23.2y,188.05h,93.98t/data=!3m6!1e1!3m4!1sFuJGq7hoHkLGO5qTS-1n4g!2e0!7i16384!8i8192Quote from: roadfro on January 08, 2019, 09:47:49 AMQuote from: jakeroot on January 08, 2019, 04:46:00 AM
Found yet another in Richmond. Southbound Aviation at Grant McConachie Way.
http://bit.ly/2GXQFHK -- << street view shot from 2015
I think the intersection was formerly a single-lane left, but was changed to a dual left, though tire marks suggest it's always been a dual left turn (with an option lane).
Any idea if this still operates with permissive phasing? I'd check myself but have a swamped schedule down here in Seattle. No free days for a while.
This street view from August 2018 (https://goo.gl/maps/yGV8DoHSoF12) seems to suggest it's operating in split phase.
It should be noted that Canada uses flashing green arrows during the protected phase at most lights. At least the ones in BC operate at 2 flashes per second, so they are not always picked up on camera. Since something like 90% of traffic lights in Vancouver operate with permissive phasing (very high understanding of yielding on green), something tells me that drivers in the street view images would not continue turning across traffic without a green arrow. I'm guessing we just can't see it.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on January 17, 2019, 04:02:54 PM
Post by: Amtrakprod on January 17, 2019, 04:02:54 PM
Found one in Indiana: https://www.google.com/maps/@38.9579252,-85.8625074,3a,71.9y,334.06h,73.84t/data=!3m6!1e1!3m4!1sjFSq9kYJFmwIV2so6GGPDQ!2e0!7i13312!8i6656
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 17, 2019, 04:29:40 PM
Post by: jakeroot on January 17, 2019, 04:29:40 PM
Quote from: Amtrakprod on January 17, 2019, 04:02:54 PM
Found one in Indiana: https://www.google.com/maps/@38.9579252,-85.8625074,3a,71.9y,334.06h,73.84t/data=!3m6!1e1!3m4!1sjFSq9kYJFmwIV2so6GGPDQ!2e0!7i13312!8i6656
Cool, thanks for sharing! Interesting to note that the signals were replaced in or around 2016, so the local agency responsible for the signals must think they're working OK. Otherwise, I assume they would have removed them. Many of the signals first posted in this thread have been removed, probably for similar reasons (change of heart on the part of the responsible agency, I suspect).
Title: Re: Double left turns with permissive phasing
Post by: Revive 755 on January 18, 2019, 10:36:10 PM
Post by: Revive 755 on January 18, 2019, 10:36:10 PM
There's a left plus left-thru-right at the Potomac Boulevard intersection with IL 15 in Mount Vernon just west of I-64/I-57 that appears to use permissive phasing. Streetview. (https://goo.gl/maps/6w2X4Tt7dYp)
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 19, 2019, 02:06:14 AM
Post by: jakeroot on January 19, 2019, 02:06:14 AM
Quote from: Revive 755 on January 18, 2019, 10:36:10 PM
There's a left plus left-thru-right at the Potomac Boulevard intersection with IL 15 in Mount Vernon just west of I-64/I-57 that appears to use permissive phasing. Streetview. (https://goo.gl/maps/6w2X4Tt7dYp)
Sure looks like it. The double "YIELD ON GREEN" signs seem to be the obvious giveaway, although I'd like to find some street view position that showed it in its permissive phase at some point (on mobile at the moment).
Title: Re: Double left turns with permissive phasing
Post by: bcroadguy on January 19, 2019, 05:28:03 AM
Post by: bcroadguy on January 19, 2019, 05:28:03 AM
Quote from: jakeroot on January 08, 2019, 11:25:02 AMQuote from: roadfro on January 08, 2019, 09:47:49 AMQuote from: jakeroot on January 08, 2019, 04:46:00 AM
Found yet another in Richmond. Southbound Aviation at Grant McConachie Way.
http://bit.ly/2GXQFHK -- << street view shot from 2015
I think the intersection was formerly a single-lane left, but was changed to a dual left, though tire marks suggest it's always been a dual left turn (with an option lane).
Any idea if this still operates with permissive phasing? I'd check myself but have a swamped schedule down here in Seattle. No free days for a while.
This street view from August 2018 (https://goo.gl/maps/yGV8DoHSoF12) seems to suggest it's operating in split phase.
It should be noted that Canada uses flashing green arrows during the protected phase at most lights. At least the ones in BC operate at 2 flashes per second, so they are not always picked up on camera. Since something like 90% of traffic lights in Vancouver operate with permissive phasing (very high understanding of yielding on green), something tells me that drivers in the street view images would not continue turning across traffic without a green arrow. I'm guessing we just can't see it.
It's almost definitely not split phase. All the double left split phase signals I've seen in BC use non-flashing arrows
(Examples: https://www.google.com/maps/@49.2329204,-122.8526462,3a,44y,187.49h,86.45t/data=!3m6!1e1!3m4!1sO1weXeBIgAFtF5WRu70vrA!2e0!7i13312!8i6656, https://www.google.com/maps/@49.2307959,-122.6894904,3a,19.9y,3.87h,90.51t/data=!3m6!1e1!3m4!1slFZVfZhYrRmC0fS_rG9B4w!2e0!7i13312!8i6656)
I think you found yourself a permissive double left :)
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on January 19, 2019, 11:51:54 AM
Post by: Amtrakprod on January 19, 2019, 11:51:54 AM
Never thought I would find this, and sadly it has been changed, but I found one in downtown Springfield MA:
Title: Re: Double left turns with permissive phasing
Post by: bcroadguy on January 21, 2019, 05:36:14 AM
Post by: bcroadguy on January 21, 2019, 05:36:14 AM
Quote from: Amtrakprod on January 19, 2019, 11:51:54 AM
Never thought I would find this, and sadly it has been changed, but I found one in downtown Springfield MA:
I wonder what the top part of that signal does. It's weird how it has four lights but the bottom one is a solid green. Two reds for extra emphasis maybe?
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on January 21, 2019, 08:06:22 AM
Post by: Amtrakprod on January 21, 2019, 08:06:22 AM
Quote from: bcroadguy on January 21, 2019, 05:36:14 AMNope, sometimes MA just uses an extra section, I have no idea why :spin: :spin: :spin:Quote from: Amtrakprod on January 19, 2019, 11:51:54 AM
Never thought I would find this, and sadly it has been changed, but I found one in downtown Springfield MA:
I wonder what the top part of that signal does. It's weird how it has four lights but the bottom one is a solid green. Two reds for extra emphasis maybe?
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 21, 2019, 11:55:36 AM
Post by: jakeroot on January 21, 2019, 11:55:36 AM
^^
I'm guessing the second-to-bottom lens is unused, since that was the section that previously displayed a green orb. Not sure why they didn't just disable the bottom green arrow.
Either way, cool that a double left yield existed in Mass for a short time!
EDIT: I checked out the old intersection (http://bit.ly/2FFrSXu) on Google Maps. The top two sections appear to have been red displays: the top was a red orb, and the second-to-top was a red arrow. I'm guessing the bottom two were a yellow orb or yellow arrow, and then a green arrow.
I'm guessing the second-to-bottom lens is unused, since that was the section that previously displayed a green orb. Not sure why they didn't just disable the bottom green arrow.
Either way, cool that a double left yield existed in Mass for a short time!
EDIT: I checked out the old intersection (http://bit.ly/2FFrSXu) on Google Maps. The top two sections appear to have been red displays: the top was a red orb, and the second-to-top was a red arrow. I'm guessing the bottom two were a yellow orb or yellow arrow, and then a green arrow.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on January 21, 2019, 02:14:24 PM
Post by: Amtrakprod on January 21, 2019, 02:14:24 PM
Quote from: jakeroot on January 21, 2019, 11:55:36 AMThe unused section is the second to the top.
^^
I'm guessing the second-to-bottom lens is unused, since that was the section that previously displayed a green orb. Not sure why they didn't just disable the bottom green arrow.
Either way, cool that a double left yield existed in Mass for a short time!
EDIT: I checked out the old intersection (http://bit.ly/2FFrSXu) on Google Maps. The top two sections appear to have been red displays: the top was a red orb, and the second-to-top was a red arrow. I'm guessing the bottom two were a yellow orb or yellow arrow, and then a green arrow.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 21, 2019, 03:31:45 PM
Post by: jakeroot on January 21, 2019, 03:31:45 PM
Quote from: Amtrakprod on January 21, 2019, 02:14:24 PM
The unused section is the second to the top.
Is that the case now? In my Street View link, the second-to-top lens is still in use as a red left arrow.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on January 21, 2019, 07:41:26 PM
Post by: Amtrakprod on January 21, 2019, 07:41:26 PM
Quote from: jakeroot on January 21, 2019, 03:31:45 PMI'm pretty sure this left turn is illegal now, I'll check as I'm going to Springfield next weekend.Quote from: Amtrakprod on January 21, 2019, 02:14:24 PM
The unused section is the second to the top.
Is that the case now? In my Street View link, the second-to-top lens is still in use as a red left arrow.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 07, 2019, 02:07:24 PM
Post by: jakeroot on April 07, 2019, 02:07:24 PM
I have located bigfoot...a signalized one in California. And it's in Santa Clara County, which is not exactly known for permissive phasing. The unsignalized one was in Cupertino (http://bit.ly/2AegGww) at the Apple Headquarters, only a short walk away.
Agilent Technologies business estate @ Stevens Creek Blvd (http://bit.ly/2D3nWgb)
(2008 GSV with green signals displayed (turn camera around) (http://bit.ly/2uQV5ar)) (modern-day GSV with [Clearview] "YIELD ON GREEN" signs (http://bit.ly/2WRG6Jf)).
The signal was actually updated a few years ago, to move Steven Creek Blvd's median-mounted left turn signals overhead. Most other signals were replaced as well. Rather than putting in split-phasing, the engineer responsible instead decided to repaint the left turn guidance lines and install "YIELD ON GREEN" signs. So clearly, this install was not an accident.
(https://i.imgur.com/XEBrr8l.png)
Agilent Technologies business estate @ Stevens Creek Blvd (http://bit.ly/2D3nWgb)
(2008 GSV with green signals displayed (turn camera around) (http://bit.ly/2uQV5ar)) (modern-day GSV with [Clearview] "YIELD ON GREEN" signs (http://bit.ly/2WRG6Jf)).
The signal was actually updated a few years ago, to move Steven Creek Blvd's median-mounted left turn signals overhead. Most other signals were replaced as well. Rather than putting in split-phasing, the engineer responsible instead decided to repaint the left turn guidance lines and install "YIELD ON GREEN" signs. So clearly, this install was not an accident.
(https://i.imgur.com/XEBrr8l.png)
Title: Re: Double left turns with permissive phasing
Post by: mrsman on April 14, 2019, 01:01:36 AM
Post by: mrsman on April 14, 2019, 01:01:36 AM
Quote from: jakeroot on April 07, 2019, 02:07:24 PM
I have located bigfoot...a signalized one in California. And it's in Santa Clara County, which is not exactly known for permissive phasing. The unsignalized one was in Cupertino (http://bit.ly/2AegGww) at the Apple Headquarters, only a short walk away.
Agilent Technologies business estate @ Stevens Creek Blvd (http://bit.ly/2D3nWgb)
(2008 GSV with green signals displayed (turn camera around) (http://bit.ly/2uQV5ar)) (modern-day GSV with [Clearview] "YIELD ON GREEN" signs (http://bit.ly/2WRG6Jf)).
The signal was actually updated a few years ago, to move Steven Creek Blvd's median-mounted left turn signals overhead. Most other signals were replaced as well. Rather than putting in split-phasing, the engineer responsible instead decided to repaint the left turn guidance lines and install "YIELD ON GREEN" signs. So clearly, this install was not an accident.
(https://i.imgur.com/XEBrr8l.png)
Is there anybody out inthe Cupertino area who can verify that the signal actually operates in this way, i.e. that the traffic signals facing the driveways coming from the north and the south are green at the same time such that the double left turn has to be made against opposing traffic?
While that is a possibility, there is also the possibility that this signal could be split-phased without pedestrian protection. This means that the northbound traffic and southbound traffic have greens at separate phases of the cycle, yet pedestrians face walk during both parts of the NB and SB phases. So if you make a left turn, you will not need to yield to on-coming traffic, but you should still yield to the pedestrians.
Having lived in CA, I find it odd that they would ever allow a permissive double left, so it would be nice if someone has seen this signal in action.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 14, 2019, 03:39:20 AM
Post by: jakeroot on April 14, 2019, 03:39:20 AM
Quote from: mrsman on April 14, 2019, 01:01:36 AM
Is there anybody out inthe Cupertino area who can verify that the signal actually operates in this way, i.e. that the traffic signals facing the driveways coming from the north and the south are green at the same time such that the double left turn has to be made against opposing traffic?
While that is a possibility, there is also the possibility that this signal could be split-phased without pedestrian protection. This means that the northbound traffic and southbound traffic have greens at separate phases of the cycle, yet pedestrians face walk during both parts of the NB and SB phases. So if you make a left turn, you will not need to yield to on-coming traffic, but you should still yield to the pedestrians.
Having lived in CA, I find it odd that they would ever allow a permissive double left, so it would be nice if someone has seen this signal in action.
If you look at the GSV link I posted (first one from 2008), you can see both directions green at the same time. And, that was before the installation of the pictured "YIELD ON GREEN" signs, which seems to have occurred only recently. So all things point to this being a permissive double left turn.
Nevertheless, it is indeed very possible that it now operates with split phasing, despite the signage and prior street view images. But that seems less likely given the available evidence.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on April 14, 2019, 08:23:14 AM
Post by: mrsman on April 14, 2019, 08:23:14 AM
Quote from: jakeroot on April 14, 2019, 03:39:20 AMQuote from: mrsman on April 14, 2019, 01:01:36 AM
Is there anybody out inthe Cupertino area who can verify that the signal actually operates in this way, i.e. that the traffic signals facing the driveways coming from the north and the south are green at the same time such that the double left turn has to be made against opposing traffic?
While that is a possibility, there is also the possibility that this signal could be split-phased without pedestrian protection. This means that the northbound traffic and southbound traffic have greens at separate phases of the cycle, yet pedestrians face walk during both parts of the NB and SB phases. So if you make a left turn, you will not need to yield to on-coming traffic, but you should still yield to the pedestrians.
Having lived in CA, I find it odd that they would ever allow a permissive double left, so it would be nice if someone has seen this signal in action.
If you look at the GSV link I posted (first one from 2008), you can see both directions green at the same time. And, that was before the installation of the pictured "YIELD ON GREEN" signs, which seems to have occurred only recently. So all things point to this being a permissive double left turn.
Nevertheless, it is indeed very possible that it now operates with split phasing, despite the signage and prior street view images. But that seems less likely given the available evidence.
You may be right. I generally do not like split-phasing, since it usually causes a lot of signal delay, but in a case where two private drive ways face each other, split-phasing works well.
Also, between 2008 and today, based only on GSV since I haven't been on this street, the city painted skip lines to mark the left turns as well as putting on the left turn yield on green signage. Perhaps in 2008, the private company simply painted the arrows they wanted without checking into the proper state traffic application. The authorities seem to have caught on, and made accommodations for it with the skip lines and the signage. Whether this also means that they adjusted the signal timing is an open question that can only be verified with someone driving by and observing it.
THe pedestrian crossing also complicates things and probably is what is preventing the installation of left turn arrows.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 30, 2019, 02:27:44 AM
Post by: jakeroot on April 30, 2019, 02:27:44 AM
Found another one in British Columbia (bcroadguy). Another proper one...no option lanes, no one-way streets. Just a regular four-way signal:
Westminster Highway to southbound Nelson Road (http://bit.ly/2GT1w3C) (Street View (http://bit.ly/2PBPYVj))
I think it's in Richmond, but it looks like a provincial install (modified in 2011 with the new ramps from Hwy 91). Interestingly, it was only built in 2016. Certainly one of the newest double permissive left turns that I know of. Many are quite old. There is a protected left turn signal that was installed for the opposing single-lane left turn, but it has been bagged for about 4 years now, with the turn remaining as fully permissive.
I've modified the below photo with dashed black lines, to show that the truck with the red trailer isn't going straight.
(https://i.imgur.com/KX7dfxv.png)
Westminster Highway to southbound Nelson Road (http://bit.ly/2GT1w3C) (Street View (http://bit.ly/2PBPYVj))
I think it's in Richmond, but it looks like a provincial install (modified in 2011 with the new ramps from Hwy 91). Interestingly, it was only built in 2016. Certainly one of the newest double permissive left turns that I know of. Many are quite old. There is a protected left turn signal that was installed for the opposing single-lane left turn, but it has been bagged for about 4 years now, with the turn remaining as fully permissive.
I've modified the below photo with dashed black lines, to show that the truck with the red trailer isn't going straight.
(https://i.imgur.com/KX7dfxv.png)
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on June 08, 2019, 07:37:32 PM
Post by: Amtrakprod on June 08, 2019, 07:37:32 PM
https://www.google.com/maps/@44.8568317,-93.2432461,3a,75y,342.6h,83.19t/data=!3m6!1e1!3m4!1sjAmxiFpEG17jHa_ZkhIRtA!2e0!7i13312!8i6656
Many of these in Bloomington MN
Many of these in Bloomington MN
Title: Re: Double left turns with permissive phasing
Post by: MNHighwayMan on June 09, 2019, 10:35:42 AM
Post by: MNHighwayMan on June 09, 2019, 10:35:42 AM
Quote from: Amtrakprod on June 08, 2019, 07:37:32 PM
https://www.google.com/maps/@44.8568317,-93.2432461,3a,75y,342.6h,83.19t/data=!3m6!1e1!3m4!1sjAmxiFpEG17jHa_ZkhIRtA!2e0!7i13312!8i6656
Many of these in Bloomington MN
Did you actually see any of them operate with the FYA though? I've noticed that MnDOT/other Minnesota agencies like to install double FYA left signal heads, but these heads never actually operate with the FYA–only in protected mode.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on June 09, 2019, 04:32:17 PM
Post by: jakeroot on June 09, 2019, 04:32:17 PM
I noticed those exact signals last time I was in Minneapolis. I thought the idea was to operate them in permissive mode during off-hours, but there's scant evidence of this being true.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on June 14, 2019, 10:31:50 AM
Post by: mrsman on June 14, 2019, 10:31:50 AM
What's really odd is that there are signs on the cross street mentioning the FYA is to yield to opposing traffic. The lack of such signs on the main street leads me to believe that they probably don't allow for the FYA to actually cycle.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on July 25, 2019, 09:15:27 PM
Post by: mrsman on July 25, 2019, 09:15:27 PM
As I was GSVing around the DC area to come up with some examples for another thread, I came across this intersection.
I don't know if 1.5 lanes counts for your critera, but here is a case with left lane turning left and second lane allowing the option to turn left or go straight. In most cases, such a signal would be signalized with split-phasing, which is a special case of protected only lead-lag phasing where the opposing directions do not overlap at all.
In this case, the signal allow for permissive left turns. During afternoon rush hour, a lagging left arrow comes up at the end of the cycle. To prevent yellow trap, electronic "No left turn" signs are illuminated in the opposite direction during those times. I don't believe the arrow comes up at all outside of rush hour.
12th and Independence SW. The left turn leads towards the 14th Street bridge to Virginia. (No left turn allowed from Independence to 14th, so drivers take Independence to 12th to C to 14th.)
https://www.google.com/maps/@38.8876192,-77.0274115,3a,75y,276.43h,65.49t/data=!3m6!1e1!3m4!1s1WXyRW6UOqHw3btPpy1ZHg!2e0!7i16384!8i8192
I don't know if 1.5 lanes counts for your critera, but here is a case with left lane turning left and second lane allowing the option to turn left or go straight. In most cases, such a signal would be signalized with split-phasing, which is a special case of protected only lead-lag phasing where the opposing directions do not overlap at all.
In this case, the signal allow for permissive left turns. During afternoon rush hour, a lagging left arrow comes up at the end of the cycle. To prevent yellow trap, electronic "No left turn" signs are illuminated in the opposite direction during those times. I don't believe the arrow comes up at all outside of rush hour.
12th and Independence SW. The left turn leads towards the 14th Street bridge to Virginia. (No left turn allowed from Independence to 14th, so drivers take Independence to 12th to C to 14th.)
https://www.google.com/maps/@38.8876192,-77.0274115,3a,75y,276.43h,65.49t/data=!3m6!1e1!3m4!1s1WXyRW6UOqHw3btPpy1ZHg!2e0!7i16384!8i8192
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 26, 2019, 10:21:49 PM
Post by: jakeroot on July 26, 2019, 10:21:49 PM
Quote from: mrsman on July 25, 2019, 09:15:27 PM
As I was GSVing around the DC area to come up with some examples for another thread, I came across this intersection.
I don't know if 1.5 lanes counts for your critera, but here is a case with left lane turning left and second lane allowing the option to turn left or go straight. In most cases, such a signal would be signalized with split-phasing, which is a special case of protected only lead-lag phasing where the opposing directions do not overlap at all.
In this case, the signal allow for permissive left turns. During afternoon rush hour, a lagging left arrow comes up at the end of the cycle. To prevent yellow trap, electronic "No left turn" signs are illuminated in the opposite direction during those times. I don't believe the arrow comes up at all outside of rush hour.
12th and Independence SW. The left turn leads towards the 14th Street bridge to Virginia. (No left turn allowed from Independence to 14th, so drivers take Independence to 12th to C to 14th.)
https://www.google.com/maps/@38.8876192,-77.0274115,3a,75y,276.43h,65.49t/data=!3m6!1e1!3m4!1s1WXyRW6UOqHw3btPpy1ZHg!2e0!7i16384!8i8192
Very familiar with this intersection! My mother makes that left turn every day on her way home from work. I don't know why I didn't post about it before.
I took a video of the intersection a month ago. Very messy intersection.
https://youtu.be/x5RbNLwuoqc
There's another North of the Capitol. Louisiana @ New Jersey (NW).
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on August 15, 2019, 04:05:03 AM
Post by: jakeroot on August 15, 2019, 04:05:03 AM
Managed to find another, this one in Lakewood, WA (and probably the only one ever in Lakewood), although the whole intersection was rebuilt around 2013 and it was removed in favor of split-phasing.
Approaching South Tacoma Way from 84 St S, the left turns (which also featured a straight-on option lane) operated as fully permissive, opposite a driveway that I'm sure was lightly used.
https://goo.gl/maps/Q493n5J1BnZ4WRbJ6
(https://i.imgur.com/a95TTpM.png)
Approaching South Tacoma Way from 84 St S, the left turns (which also featured a straight-on option lane) operated as fully permissive, opposite a driveway that I'm sure was lightly used.
https://goo.gl/maps/Q493n5J1BnZ4WRbJ6
(https://i.imgur.com/a95TTpM.png)
Title: Re: Double left turns with permissive phasing
Post by: mrsman on August 15, 2019, 04:58:06 PM
Post by: mrsman on August 15, 2019, 04:58:06 PM
Here's one that I just discovered on my recent NYC trip a few days ago:
https://www.google.com/maps/@40.6101192,-73.9222153,3a,75y,201.3h,78.86t/data=!3m6!1e1!3m4!1sSyD5M_GVBc69m-5QgG_hIg!2e0!7i16384!8i8192
Ave U / Flatbush in Brooklyn.
While it's technically double permissive, it is so busy most of the time that most people will not be able to turn without the arrow anyway.
https://www.google.com/maps/@40.6101192,-73.9222153,3a,75y,201.3h,78.86t/data=!3m6!1e1!3m4!1sSyD5M_GVBc69m-5QgG_hIg!2e0!7i16384!8i8192
Ave U / Flatbush in Brooklyn.
While it's technically double permissive, it is so busy most of the time that most people will not be able to turn without the arrow anyway.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on August 16, 2019, 02:28:47 AM
Post by: jakeroot on August 16, 2019, 02:28:47 AM
Quote from: mrsman on August 15, 2019, 04:58:06 PM
Here's one that I just discovered on my recent NYC trip a few days ago:
https://www.google.com/maps/@40.6101192,-73.9222153,3a,75y,201.3h,78.86t/data=!3m6!1e1!3m4!1sSyD5M_GVBc69m-5QgG_hIg!2e0!7i16384!8i8192
Ave U / Flatbush in Brooklyn.
While it's technically double permissive, it is so busy most of the time that most people will not be able to turn without the arrow anyway.
Nice find! NYC seems to have more of these than one might think. Flatbush apparently has at least two (also at Tillary).
Title: Re: Double left turns with permissive phasing
Post by: mrsman on August 16, 2019, 03:57:32 PM
Post by: mrsman on August 16, 2019, 03:57:32 PM
Quote from: jakeroot on August 16, 2019, 02:28:47 AMQuote from: mrsman on August 15, 2019, 04:58:06 PM
Here's one that I just discovered on my recent NYC trip a few days ago:
https://www.google.com/maps/@40.6101192,-73.9222153,3a,75y,201.3h,78.86t/data=!3m6!1e1!3m4!1sSyD5M_GVBc69m-5QgG_hIg!2e0!7i16384!8i8192
Ave U / Flatbush in Brooklyn.
While it's technically double permissive, it is so busy most of the time that most people will not be able to turn without the arrow anyway.
That's true, but so far the other NYC examples mentioned above tend to be in places where the opposing left is prohibited for some reason (usually because of a one-way street). A permissive double left is generally easier to implement when the opposing left is prohibited, as cars making the opposing left tend to block the clear view of the oncoming traffic. [It also allowes for lagging lefts without worry of yellow trap, which tends to be beneficial, especially if one of the left turn lanes is an option lane.]
The interesting thing about Ave U turning onto Flatbush is that both directions can turn PPLT (and the westbound left is double lane). I believe this is unique in NYC.
Nice find! NYC seems to have more of these than one might think. Flatbush apparently has at least two (also at Tillary).
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on August 17, 2019, 11:53:42 PM
Post by: jakeroot on August 17, 2019, 11:53:42 PM
Quote from: mrsman on August 16, 2019, 03:57:32 PMQuote from: jakeroot on August 16, 2019, 02:28:47 AM
Nice find! NYC seems to have more of these than one might think. Flatbush apparently has at least two (also at Tillary).
That's true, but so far the other NYC examples mentioned above tend to be in places where the opposing left is prohibited for some reason (usually because of a one-way street). A permissive double left is generally easier to implement when the opposing left is prohibited, as cars making the opposing left tend to block the clear view of the oncoming traffic. [It also allowes for lagging lefts without worry of yellow trap, which tends to be beneficial, especially if one of the left turn lanes is an option lane.]
This is also true. But even with that in mind, many locales still tend to use protected-only phasing for all double left turns, irrespective of the individual characteristics of a particular intersection (which may or may not allow its implementation given any potential hazards). What impresses me about New York (the city? Surrounding counties?) is that they don't outright ban the installation of these types of setups. Many individual cities in the country don't ban them (opposite the situation of many state DOTs, which do ban the practice), but New York is impressive in that they have quite a few, which is more than I can say about most cities.
Title: Double left turns with permissive phasing
Post by: Amtrakprod on August 18, 2019, 10:48:55 AM
Post by: Amtrakprod on August 18, 2019, 10:48:55 AM
Quote from: mrsman on August 15, 2019, 04:58:06 PMI honestly think New York State might rank last in traffic signals
Here's one that I just discovered on my recent NYC trip a few days ago:
https://www.google.com/maps/@40.6101192,-73.9222153,3a,75y,201.3h,78.86t/data=!3m6!1e1!3m4!1sSyD5M_GVBc69m-5QgG_hIg!2e0!7i16384!8i8192
Ave U / Flatbush in Brooklyn.
While it's technically double permissive, it is so busy most of the time that most people will not be able to turn without the arrow anyway.
iPhone
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on August 18, 2019, 03:01:27 PM
Post by: jakeroot on August 18, 2019, 03:01:27 PM
Quote from: Amtrakprod on August 18, 2019, 10:48:55 AM
I honestly think New York State might rank last in traffic signals
In terms of what? The intersection that mrsman linked to is pretty comprehensive, and the signals are very visible. Hell of a lot better than some other places.
Title: Re: Double left turns with permissive phasing
Post by: steviep24 on August 18, 2019, 04:47:44 PM
Post by: steviep24 on August 18, 2019, 04:47:44 PM
Quote from: Amtrakprod on August 18, 2019, 10:48:55 AMNew York City certainly does things differently than NYSDOT (or anywhere else for that matter but the signals linked above are not that bad.Quote from: mrsman on August 15, 2019, 04:58:06 PMI honestly think New York State might rank last in traffic signals
Here's one that I just discovered on my recent NYC trip a few days ago:
https://www.google.com/maps/@40.6101192,-73.9222153,3a,75y,201.3h,78.86t/data=!3m6!1e1!3m4!1sSyD5M_GVBc69m-5QgG_hIg!2e0!7i16384!8i8192
Ave U / Flatbush in Brooklyn.
While it's technically double permissive, it is so busy most of the time that most people will not be able to turn without the arrow anyway.
iPhone
Title: Re: Double left turns with permissive phasing
Post by: Rothman on August 18, 2019, 08:30:26 PM
Post by: Rothman on August 18, 2019, 08:30:26 PM
I'd like to hear more about how NYSDOT ranks last in signals.
Title: Re: Double left turns with permissive phasing
Post by: Revive 755 on August 19, 2019, 06:29:23 PM
Post by: Revive 755 on August 19, 2019, 06:29:23 PM
Quote from: jakeroot on August 18, 2019, 03:01:27 PMQuote from: Amtrakprod on August 18, 2019, 10:48:55 AM
I honestly think New York State might rank last in traffic signals
In terms of what? The intersection that mrsman linked to is pretty comprehensive, and the signals are very visible. Hell of a lot better than some other places.
For the linked photo at Flatbrush and Avenue U:
* No backplates on any heads.
* Given the number of lanes and amount traffic, IMHO all of the far side indications need to be 12".
* The 12" arrows next to 8" circular indications in a cluster/offset configuration doesn't look right. If these are not outright non-MUTCD compliant they are certainly pushing the limits.
* There are not any heads directly over the roadway on Avenue U - only off to the side heads. Off to the side heads can be to hard to quickly find if the driver is busy with other tasks such as navigation. I would be curious as to the number of red light violations for those legs and number of angle accidents for the intersection.
* I'm not seeing any visors on the pedestrian signals
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on August 21, 2019, 06:43:26 AM
Post by: Amtrakprod on August 21, 2019, 06:43:26 AM
Quote from: Rothman on August 18, 2019, 08:30:26 PMMaybe we should move this onto my ranking states by traffic lights topic, but there aren't enough signals per lanes, and no backplates. It's a sloppy set up.
I'd like to hear more about how NYSDOT ranks last in signals.
iPhone
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on August 21, 2019, 06:44:11 AM
Post by: Amtrakprod on August 21, 2019, 06:44:11 AM
Quote from: Revive 755 on August 19, 2019, 06:29:23 PMYep all of thatQuote from: jakeroot on August 18, 2019, 03:01:27 PMQuote from: Amtrakprod on August 18, 2019, 10:48:55 AM
I honestly think New York State might rank last in traffic signals
In terms of what? The intersection that mrsman linked to is pretty comprehensive, and the signals are very visible. Hell of a lot better than some other places.
For the linked photo at Flatbrush and Avenue U:
* No backplates on any heads.
* Given the number of lanes and amount traffic, IMHO all of the far side indications need to be 12".
* The 12" arrows next to 8" circular indications in a cluster/offset configuration doesn't look right. If these are not outright non-MUTCD compliant they are certainly pushing the limits.
* There are not any heads directly over the roadway on Avenue U - only off to the side heads. Off to the side heads can be to hard to quickly find if the driver is busy with other tasks such as navigation. I would be curious as to the number of red light violations for those legs and number of angle accidents for the intersection.
* I'm not seeing any visors on the pedestrian signals
iPhone
Title: Re: Double left turns with permissive phasing
Post by: jeffandnicole on August 21, 2019, 08:01:28 AM
Post by: jeffandnicole on August 21, 2019, 08:01:28 AM
Quote from: Revive 755 on August 19, 2019, 06:29:23 PMQuote from: jakeroot on August 18, 2019, 03:01:27 PMQuote from: Amtrakprod on August 18, 2019, 10:48:55 AM
I honestly think New York State might rank last in traffic signals
In terms of what? The intersection that mrsman linked to is pretty comprehensive, and the signals are very visible. Hell of a lot better than some other places.
For the linked photo at Flatbrush and Avenue U:
* No backplates on any heads.
* Given the number of lanes and amount traffic, IMHO all of the far side indications need to be 12".
* The 12" arrows next to 8" circular indications in a cluster/offset configuration doesn't look right. If these are not outright non-MUTCD compliant they are certainly pushing the limits.
* There are not any heads directly over the roadway on Avenue U - only off to the side heads. Off to the side heads can be to hard to quickly find if the driver is busy with other tasks such as navigation. I would be curious as to the number of red light violations for those legs and number of angle accidents for the intersection.
* I'm not seeing any visors on the pedestrian signals
I don't know how many intersections with traffic lights there are in New York City, but you pretty much named every condition found at every intersection.
For that...
Backplates are never required. When the speed limit is 45 mph or above, they should have them, but not shall have them. Many intersections throughout the country don't have them. I'd even go as far to say that the majority of traffic lights country-wide don't have them.
8" lights installed prior to the recent 12" standard in the MUTCD are explicitly permitted per the MUTCD to remain in place for the rest of their useful life.
There's nothing pushing the limits of the 12" arrows next to 8" lights.
No visors are required on pedestrian signals.
So, based on this example, everything found at this intersection confirmed to MUTCD requirements at the time of installation. And as mentioned, this is pretty much a typical NYC setup, so I don't know why this intersection was specifically shown, as it's off-topic in regards to the thread.
Title: Re: Double left turns with permissive phasing
Post by: RestrictOnTheHanger on August 21, 2019, 08:50:47 AM
Post by: RestrictOnTheHanger on August 21, 2019, 08:50:47 AM
FWIW a vast majority of NYC's signals were installed before the 2009 MUTCD came out. With new, replacement, or modified installations, they do adhere to some of the relevant standards. Those being 1 signal per lane, 12" signals on 30+mph roads, and FYAs.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on August 21, 2019, 02:45:33 PM
Post by: jakeroot on August 21, 2019, 02:45:33 PM
Quote from: Amtrakprod on August 21, 2019, 06:43:26 AMQuote from: Rothman on August 18, 2019, 08:30:26 PMMaybe we should move this onto my ranking states by traffic lights topic, but there aren't enough signals per lanes, and no backplates. It's a sloppy set up.
I'd like to hear more about how NYSDOT ranks last in signals.
There's four signals and four approach lanes, and many places don't use backplates. Plus, unlike many agencies, they've managed to balance the signals so that you can see at least one no matter where you are sitting. Many states put every signal directly across from the stop line. That is deficient for everyone except those at the front of the line.
Keep in mind that you proclaimed NYS as being "last" in traffic signals. I'm not here to pretend that NYC is the best in the business, but you're not identifying things that would make, at least the city, rank last.
Quote from: Revive 755 on August 19, 2019, 06:29:23 PM
For the linked photo at Flatbrush and Avenue U:
* No backplates on any heads.
* Given the number of lanes and amount traffic, IMHO all of the far side indications need to be 12".
* The 12" arrows next to 8" circular indications in a cluster/offset configuration doesn't look right. If these are not outright non-MUTCD compliant they are certainly pushing the limits.
* There are not any heads directly over the roadway on Avenue U - only off to the side heads. Off to the side heads can be to hard to quickly find if the driver is busy with other tasks such as navigation. I would be curious as to the number of red light violations for those legs and number of angle accidents for the intersection.
* I'm not seeing any visors on the pedestrian signals
* Backplates are nice, but it's unfair to hold it against NYC as many other places don't use them.
* 12-inch primary signals are probably wise overhead, but I don't think it's always necessary for secondary signals.
* 12-inch arrows next to 8-inch orbs were very common for a while. Still the norm in British Columbia (https://goo.gl/maps/H6Gf6QotmWZtVW8L8) (new, unactivated signals in that link). I don't see why this is a problem.
* Overhead signals are easily hidden by larger vehicles. Better to have a mix of both, kind of like the approach from Flatbush.
* As J&N indicates, pedestrian signal visors are not required. Most of the west coast does not use pedestrian signal visors (although I do like them).
I'm not going to pretend like this setup is the best in the world. There are certainly some things that I would change (adding a far-side overhead signal with a backplate, adding a right-side near-side signal, and adding a backplate to the tower signal on the far side), but NYC's traditional setups should not "rank last".
Now, what should rank last (IMO)? This is a great example (https://goo.gl/maps/sxnvcJuj2ZE4z59A7) (near Graham, WA) (this is not far from where I grew up, so I can assure you there is no bias). This is a 55-mph approach. If you are behind a tall vehicle, there's a decent chance that you cannot see the signals for a good portion of the approach. None of the BS you mentioned above (backplates, indication size, etc) matters if you can't even see a signal. This is why, IMO, NYC is actually a fair bit better than NYS, and many other states. At least the city doesn't put all their eggs in one basket (all the time at least).
Title: Re: Double left turns with permissive phasing
Post by: jeffandnicole on August 21, 2019, 02:57:17 PM
Post by: jeffandnicole on August 21, 2019, 02:57:17 PM
Quote from: RestrictOnTheHanger on August 21, 2019, 08:50:47 AM
FWIW a vast majority of NYC's signals were installed before the 2009 MUTCD came out. With new, replacement, or modified installations, they do adhere to some of the relevant standards. Those being 1 signal per lane, 12" signals on 30+mph roads, and FYAs.
FYAs are optional, not standard. Some states don't have a single FYA installed.
Title: Re: Double left turns with permissive phasing
Post by: kphoger on August 21, 2019, 04:51:29 PM
Post by: kphoger on August 21, 2019, 04:51:29 PM
Quote from: jakeroot on August 21, 2019, 02:45:33 PM
Now, what should rank last (IMO)? This is a great example (https://goo.gl/maps/sxnvcJuj2ZE4z59A7) (near Graham, WA) (this is not far from where I grew up, so I can assure you there is no bias). This is a 55-mph approach. If you are behind a tall vehicle, there's a decent chance that you cannot see the signals for a good portion of the approach. None of the BS you mentioned above (backplates, indication size, etc) matters if you can't even see a signal.
The worst I've personally driven through is this example (https://goo.gl/maps/frSx7vuy4d99Q4HKA) in Coahuila. A single overhead signal for each direction of a four-lane divided federal highway with very heavy commercial traffic.
Title: Re: Double left turns with permissive phasing
Post by: steviep24 on August 21, 2019, 05:07:54 PM
Post by: steviep24 on August 21, 2019, 05:07:54 PM
^^ Those are typical of what NYC often installs. (The Flatbush and Ave U example.) Those are not NYSDOT.
These examples are typical of what NYSDOT installs outside of NYC.
Recent installations:
https://www.google.com/maps/@43.1471182,-77.7112622,3a,75y,246.57h,90t/data=!3m6!1e1!3m4!1sexC28q_yeddycXQKeGOLcQ!2e0!7i13312!8i6656?hl=en&authuser=0
https://www.google.com/maps/@43.1476884,-77.7091322,3a,75y,246.57h,90t/data=!3m6!1e1!3m4!1skk9NwnqJgq3syra0_ZUvPg!2e0!7i13312!8i6656?hl=en&authuser=0
Older installations;
https://www.google.com/maps/@43.0725792,-77.6445313,3a,75y,6.81h,90t/data=!3m6!1e1!3m4!1s_tEVblEC6eu7mTefVNiy-A!2e0!7i13312!8i6656?hl=en&authuser=0
https://www.google.com/maps/@43.0681274,-77.646874,3a,75y,210h,90t/data=!3m6!1e1!3m4!1sKERFq8yxjte_HQBcfYTtJw!2e0!7i13312!8i6656?hl=en&authuser=0
As you can see their more recent installs use back plates and often have FYA. Also, NYSDOT is big on span wire but are using mast arms a lot more than they used to. Also, for span wire installs they have been moving toward box span for large intersections. (probably to meet newer signal per lane requirements.) NYSDOT doesn't use side mounted signals except on rare occasions.
I know this has been going off topic but I thought I'd throw this in there.
These examples are typical of what NYSDOT installs outside of NYC.
Recent installations:
https://www.google.com/maps/@43.1471182,-77.7112622,3a,75y,246.57h,90t/data=!3m6!1e1!3m4!1sexC28q_yeddycXQKeGOLcQ!2e0!7i13312!8i6656?hl=en&authuser=0
https://www.google.com/maps/@43.1476884,-77.7091322,3a,75y,246.57h,90t/data=!3m6!1e1!3m4!1skk9NwnqJgq3syra0_ZUvPg!2e0!7i13312!8i6656?hl=en&authuser=0
Older installations;
https://www.google.com/maps/@43.0725792,-77.6445313,3a,75y,6.81h,90t/data=!3m6!1e1!3m4!1s_tEVblEC6eu7mTefVNiy-A!2e0!7i13312!8i6656?hl=en&authuser=0
https://www.google.com/maps/@43.0681274,-77.646874,3a,75y,210h,90t/data=!3m6!1e1!3m4!1sKERFq8yxjte_HQBcfYTtJw!2e0!7i13312!8i6656?hl=en&authuser=0
As you can see their more recent installs use back plates and often have FYA. Also, NYSDOT is big on span wire but are using mast arms a lot more than they used to. Also, for span wire installs they have been moving toward box span for large intersections. (probably to meet newer signal per lane requirements.) NYSDOT doesn't use side mounted signals except on rare occasions.
I know this has been going off topic but I thought I'd throw this in there.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on August 22, 2019, 01:26:17 AM
Post by: jakeroot on August 22, 2019, 01:26:17 AM
Quote from: kphoger on August 21, 2019, 04:51:29 PMQuote from: jakeroot on August 21, 2019, 02:45:33 PM
Now, what should rank last (IMO)? This is a great example (https://goo.gl/maps/sxnvcJuj2ZE4z59A7) (near Graham, WA) (this is not far from where I grew up, so I can assure you there is no bias). This is a 55-mph approach. If you are behind a tall vehicle, there's a decent chance that you cannot see the signals for a good portion of the approach. None of the BS you mentioned above (backplates, indication size, etc) matters if you can't even see a signal.
The worst I've personally driven through is this example (https://goo.gl/maps/frSx7vuy4d99Q4HKA) in Coahuila. A single overhead signal for each direction of a four-lane divided federal highway with very heavy commercial traffic.
Yikes, that is bad. Looks to run split-phasing as well. Also not so good.
Quote from: steviep24 on August 21, 2019, 05:07:54 PM
I know this has been going off topic but I thought I'd throw this in there.
No no, it's good. I'm glad you brought it up (despite my terrible attempt in my own post). Amtrakprod indicated that the above signal at Flatbush/Ave U was a good example of how New York State "ranks last" in signals, despite it being a NYC install. Even I know, living primarily on the opposite side of the country, that the state has totally different traffic signals. IMO, they're not as good as the city, although they have newer features (backplates, signal per lane) that give the appearance of being "better". I still prefer NYC signals, though, on account of their placement strategies.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on August 22, 2019, 09:25:29 PM
Post by: mrsman on August 22, 2019, 09:25:29 PM
Quote from: jakeroot on August 22, 2019, 01:26:17 AMQuote from: kphoger on August 21, 2019, 04:51:29 PMQuote from: jakeroot on August 21, 2019, 02:45:33 PM
Now, what should rank last (IMO)? This is a great example (https://goo.gl/maps/sxnvcJuj2ZE4z59A7) (near Graham, WA) (this is not far from where I grew up, so I can assure you there is no bias). This is a 55-mph approach. If you are behind a tall vehicle, there's a decent chance that you cannot see the signals for a good portion of the approach. None of the BS you mentioned above (backplates, indication size, etc) matters if you can't even see a signal.
The worst I've personally driven through is this example (https://goo.gl/maps/frSx7vuy4d99Q4HKA) in Coahuila. A single overhead signal for each direction of a four-lane divided federal highway with very heavy commercial traffic.
Yikes, that is bad. Looks to run split-phasing as well. Also not so good.Quote from: steviep24 on August 21, 2019, 05:07:54 PM
I know this has been going off topic but I thought I'd throw this in there.
No no, it's good. I'm glad you brought it up (despite my terrible attempt in my own post). Amtrakprod indicated that the above signal at Flatbush/Ave U was a good example of how New York State "ranks last" in signals, despite it being a NYC install. Even I know, living primarily on the opposite side of the country, that the state has totally different traffic signals. IMO, they're not as good as the city, although they have newer features (backplates, signal per lane) that give the appearance of being "better". I still prefer NYC signals, though, on account of their placement strategies.
NYC definitely operates on a "if it ain't broke don't fix it" mentality. As mentioned on other threads, they are still using 1960's tech on all their signals except to the extant it has been superseded by MUTCD. Many 8-8-8 signals. Guy wires.
Signal placement has definitely improved at many intersections. A common NYC install was to have lamppost masts at two diagonally opposite corners. A guy wire mast arm would extend diagonally into the intersection from each lamppost mast. Hanging from the mast arm would be a four-sided* 8-8-8 signal head. As noted by others above, this means that the locations are not ideal and it's often hard to see the signals as they won't be placed where the driver is looking.
See this example: 5 Av / 9 St in Brooklyn
https://www.google.com/maps/@40.6692312,-73.9862775,3a,75y,105.55h,91.21t/data=!3m7!1e1!3m5!1sQt9FaaiXXeypuuBnhYRVcg!2e0!6s%2F%2Fgeo1.ggpht.com%2Fcbk%3Fpanoid%3DQt9FaaiXXeypuuBnhYRVcg%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D305.70407%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656?hl=en
But many of these intersections in NYC are being corrected and signals are getting better placement, but it's a slow process. In Manhattan, it seems to be working better, as one of the diagonal guy-wires is replaced for more conventional supplemental signals as can be seen along Lexington Ave.
https://www.google.com/maps/@40.7421612,-73.9828895,3a,75y,193.72h,91.97t/data=!3m6!1e1!3m4!1s12URtX6UkUBz9O0Wp_1rmA!2e0!7i16384!8i8192?hl=en
I don't know the history at Flatbush & U, but I would gather that it was originally a single left turn lane with a PPLT 5 signal display. With increased traffic (headed from the Mall towards Belt Parkway), they decided to make it a double left, but did not at the same time change the signal to an exclusive RA-YA-GA signal. Maybe it's laziness, but it does allow for a double permissive turn.
Give NYC some credit - Chicago would make a 5 signal display into protected only by sign (as done on Michigan Ave).
https://www.google.com/maps/@41.8845407,-87.6244069,3a,75y,342.48h,83.16t/data=!3m6!1e1!3m4!1s63MFkaHIWSj_xZE4FQ74YA!2e0!7i13312!8i6656?hl=en
* Since there are so many one-way streets in NYC, it's rare that you'll have 4-sided signal faces as 3-sided and 2 sided are more common.
Title: Re: Double left turns with permissive phasing
Post by: kphoger on August 23, 2019, 03:10:35 PM
Post by: kphoger on August 23, 2019, 03:10:35 PM
Quote from: jakeroot on August 22, 2019, 01:26:17 AMQuote from: kphoger on August 21, 2019, 04:51:29 PM
The worst I've personally driven through is this example (https://goo.gl/maps/frSx7vuy4d99Q4HKA) in Coahuila. A single overhead signal for each direction of a four-lane divided federal highway with very heavy commercial traffic.
Yikes, that is bad. Looks to run split-phasing as well. Also not so good.
While split phasing is quite common in Mexico, I don't think this one does. I could be wrong, but I don't see any left turn arrows to make me think it does either.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on August 23, 2019, 04:11:44 PM
Post by: jakeroot on August 23, 2019, 04:11:44 PM
Quote from: kphoger on August 23, 2019, 03:10:35 PMQuote from: jakeroot on August 22, 2019, 01:26:17 AMQuote from: kphoger on August 21, 2019, 04:51:29 PM
The worst I've personally driven through is this example (https://goo.gl/maps/frSx7vuy4d99Q4HKA) in Coahuila. A single overhead signal for each direction of a four-lane divided federal highway with very heavy commercial traffic.
Yikes, that is bad. Looks to run split-phasing as well. Also not so good.
While split phasing is quite common in Mexico, I don't think this one does. I could be wrong, but I don't see any left turn arrows to make me think it does either.
I was basing it on these views:
https://goo.gl/maps/ME7bkpc2ZEvL1yFPA
https://goo.gl/maps/BMJgXEpGcc6ZgCTq5
Title: Re: Double left turns with permissive phasing
Post by: kphoger on August 23, 2019, 04:18:53 PM
Post by: kphoger on August 23, 2019, 04:18:53 PM
Yeah, I noticed that too. I don't remember from personal experience, but I don't see how that would work without arrows.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on August 23, 2019, 10:54:40 PM
Post by: fwydriver405 on August 23, 2019, 10:54:40 PM
Quote from: mrsman on August 22, 2019, 09:25:29 PM
Give NYC some credit - Chicago would make a 5 signal display into protected only by sign (as done on Michigan Ave).
And recently, Boston as well with this bizarre setup. The last time I was there at that intersection (24 July 2019), many drivers flat out ignored the LEFT ON GREEN ARROW ONLY sign and turned left after yielding to oncoming traffic on the green ball like it used to be...
Kneeland St and Surface Rd:
October 2018 w/ LEFT TURN YIELD ON GREEN (https://www.google.com/maps/@42.3500953,-71.059769,3a,18.9y,314.64h,98.65t/data=!3m7!1e1!3m5!1sF-EE9XAf_JhOehYRwK472g!2e0!5s20181001T000000!7i16384!8i8192?hl=en)
19 May 2019 - present w/ LEFT ON GREEN ARROW ONLY (https://ibb.co/W3QLps3)
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on August 24, 2019, 06:54:35 AM
Post by: Amtrakprod on August 24, 2019, 06:54:35 AM
Quote from: fwydriver405 on August 23, 2019, 10:54:40 PMI've seen this in Cambridge too, what I wish Boston did instead is install a red arrow up top and not have the green/yellow ball lights work, or install straight green and yellow arrows so when the left turn phase ended the red ball could stay on.Quote from: mrsman on August 22, 2019, 09:25:29 PM
Give NYC some credit - Chicago would make a 5 signal display into protected only by sign (as done on Michigan Ave).
And recently, Boston as well with this bizarre setup. The last time I was there at that intersection (24 July 2019), many drivers flat out ignored the LEFT ON GREEN ARROW ONLY sign and turned left after yielding to oncoming traffic on the green ball like it used to be...
Kneeland St and Surface Rd:
October 2018 w/ LEFT TURN YIELD ON GREEN (https://www.google.com/maps/@42.3500953,-71.059769,3a,18.9y,314.64h,98.65t/data=!3m7!1e1!3m5!1sF-EE9XAf_JhOehYRwK472g!2e0!5s20181001T000000!7i16384!8i8192?hl=en)
19 May 2019 - present w/ LEFT ON GREEN ARROW ONLY (https://ibb.co/W3QLps3)
iPhone
Title: Re: Double left turns with permissive phasing
Post by: kphoger on August 24, 2019, 06:18:47 PM
Post by: kphoger on August 24, 2019, 06:18:47 PM
Quote from: mrsman on August 22, 2019, 09:25:29 PM
Give NYC some credit - Chicago would make a 5 signal display into protected only by sign (as done on Michigan Ave).
I was driving down Kellogg the other day and thought of you because of this sign (https://goo.gl/maps/jp36Nuo9rirbdPhx9).
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on August 24, 2019, 09:39:15 PM
Post by: fwydriver405 on August 24, 2019, 09:39:15 PM
Quote from: Amtrakprod on August 24, 2019, 06:54:35 AM
I've seen this in Cambridge too, what I wish Boston did instead is install a red arrow up top and not have the green/yellow ball lights work, or install straight green and yellow arrows so when the left turn phase ended the red ball could stay on.
If there was an issue with people "blocking the box", queuing of the left turn lanes, or accidents due to permissive left turns, I would have replaced the doghouse with FYA, and use TOD phasing to make the turns protected only during the rush hour and protected/permissive during the off-peak hours, Monday-Friday, similar to what New Hampshire does. Furthermore, I would change the phasing from leading to lagging left at this intersection as well.
BTW... your proposal of installing "straight green and yellow arrows so when the left-turn phase ends, the red ball could stay on" is prohibited in the 2009 MUTCD. See below:
Quote from: 2009 Edition Chapter 4D. Traffic Control Signal Features, Section 4D.05 Application of Steady Signal Indications
10 The following combinations of signal indications shall not be simultaneously displayed on any one signal face:
CIRCULAR RED with CIRCULAR YELLOW;
CIRCULAR GREEN with CIRCULAR RED; or
Straight-through GREEN ARROW with CIRCULAR RED;
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on August 24, 2019, 11:29:51 PM
Post by: jakeroot on August 24, 2019, 11:29:51 PM
Quote from: fwydriver405 on August 24, 2019, 09:39:15 PM
BTW... your proposal of installing "straight green and yellow arrows so when the left-turn phase ends, the red ball could stay on" is prohibited in the 2009 MUTCD. See below:Quote from: 2009 Edition Chapter 4D. Traffic Control Signal Features, Section 4D.05 Application of Steady Signal Indications
10 The following combinations of signal indications shall not be simultaneously displayed on any one signal face:
CIRCULAR RED with CIRCULAR YELLOW;
CIRCULAR GREEN with CIRCULAR RED; or
Straight-through GREEN ARROW with CIRCULAR RED;
That only applies to a "one signal face", not an overall setup. Protected turns with circular red indications are also a sort of engineering-faux pas at this point. I think it's allowed, but discouraged.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on August 25, 2019, 06:31:21 AM
Post by: Amtrakprod on August 25, 2019, 06:31:21 AM
Quote from: fwydriver405 on August 24, 2019, 09:39:15 PMI actually don't know of any Flashing yellow arrow in the state (and we have over 350 of them), that uses TOD phasing!Quote from: Amtrakprod on August 24, 2019, 06:54:35 AM
I've seen this in Cambridge too, what I wish Boston did instead is install a red arrow up top and not have the green/yellow ball lights work, or install straight green and yellow arrows so when the left turn phase ended the red ball could stay on.
If there was an issue with people "blocking the box", queuing of the left turn lanes, or accidents due to permissive left turns, I would have replaced the doghouse with FYA, and use TOD phasing to make the turns protected only during the rush hour and protected/permissive during the off-peak hours, Monday-Friday, similar to what New Hampshire does. Furthermore, I would change the phasing from leading to lagging left at this intersection as well.
BTW... your proposal of installing "straight green and yellow arrows so when the left-turn phase ends, the red ball could stay on" is prohibited in the 2009 MUTCD. See below:Quote from: 2009 Edition Chapter 4D. Traffic Control Signal Features, Section 4D.05 Application of Steady Signal Indications
10 The following combinations of signal indications shall not be simultaneously displayed on any one signal face:
CIRCULAR RED with CIRCULAR YELLOW;
CIRCULAR GREEN with CIRCULAR RED; or
Straight-through GREEN ARROW with CIRCULAR RED;
iPhone
Title: Re: Double left turns with permissive phasing
Post by: mrsman on August 25, 2019, 09:02:47 AM
Post by: mrsman on August 25, 2019, 09:02:47 AM
Quote from: Amtrakprod on August 25, 2019, 06:31:21 AMQuote from: fwydriver405 on August 24, 2019, 09:39:15 PMI actually don't know of any Flashing yellow arrow in the state (and we have over 350 of them), that uses TOD phasing!Quote from: Amtrakprod on August 24, 2019, 06:54:35 AM
I've seen this in Cambridge too, what I wish Boston did instead is install a red arrow up top and not have the green/yellow ball lights work, or install straight green and yellow arrows so when the left turn phase ended the red ball could stay on.
If there was an issue with people "blocking the box", queuing of the left turn lanes, or accidents due to permissive left turns, I would have replaced the doghouse with FYA, and use TOD phasing to make the turns protected only during the rush hour and protected/permissive during the off-peak hours, Monday-Friday, similar to what New Hampshire does. Furthermore, I would change the phasing from leading to lagging left at this intersection as well.
BTW... your proposal of installing "straight green and yellow arrows so when the left-turn phase ends, the red ball could stay on" is prohibited in the 2009 MUTCD. See below:Quote from: 2009 Edition Chapter 4D. Traffic Control Signal Features, Section 4D.05 Application of Steady Signal Indications
10 The following combinations of signal indications shall not be simultaneously displayed on any one signal face:
CIRCULAR RED with CIRCULAR YELLOW;
CIRCULAR GREEN with CIRCULAR RED; or
Straight-through GREEN ARROW with CIRCULAR RED;
iPhone
I can't speak to whether the intersection in Boston mentioned needs or doesn't need protected only left turns at all times, but I can say that there is a driver expectation in most of the country (other than some of the states in the Pacific Northwest*) that a doghouse signal (or 5 phase towers) are protected/permissive and that RA-YA-GA signals are protected only. This standard should be kept, because a sign like the one in Boston seems kind of small and is very easy to overlook. If I were driving there, I probably would not notice the sign and make a left turn on green orb even without a green arrow, and I could be subject to a ticket.
Simply change the signal to RA-YA-GA if you really want left turn on arrow only. Change it to a FYA if time of day signalling is warranted.
*Jakeroot and others can confirm but in WA state (and probably a few other nearby states) left turn on red arrow is permitted onto a one-way street or a one-way freeway onramp. There is no similar rule to my knowledge in any East Coast state.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on August 25, 2019, 09:09:57 AM
Post by: mrsman on August 25, 2019, 09:09:57 AM
Quote from: kphoger on August 24, 2019, 06:18:47 PMQuote from: mrsman on August 22, 2019, 09:25:29 PM
Give NYC some credit - Chicago would make a 5 signal display into protected only by sign (as done on Michigan Ave).
I was driving down Kellogg the other day and thought of you because of this sign (https://goo.gl/maps/jp36Nuo9rirbdPhx9).
WHile the construction makes the signal placement ugly, this sign is not nearly as bad as the Chicago or Boston examples. It seems pretty clear that the left signal controls left turns and the other two signals control straight. Seeing the red ball (especially while the other signals are green) would lead me to at least suspect that the left signal controls left turns.
While the latest MUTCD recommends (or requires, not sure how to actually interpret it) that new exclusive left turn signals have red arrows instead of red balls, there are plenty of signals out there that are R-Y-GA that control a protected only left turn. They are still very common in PA and VA which use the sign "Left turn signal". This was also the standard for a while in CA, where they had a sign that read "Left turn on arrow only" (the only arrow was a green one), but in that case the left turn signal was in a 3M or louvered so as not to confuse nearby straight traffic. Very few of those remain in CA as most have been converted to red arrow.
Title: Re: Double left turns with permissive phasing
Post by: jeffandnicole on August 25, 2019, 09:15:52 AM
Post by: jeffandnicole on August 25, 2019, 09:15:52 AM
Quote from: mrsman on August 25, 2019, 09:02:47 AMQuote from: Amtrakprod on August 25, 2019, 06:31:21 AMQuote from: fwydriver405 on August 24, 2019, 09:39:15 PMI actually don’t know of any Flashing yellow arrow in the state (and we have over 350 of them), that uses TOD phasing!Quote from: Amtrakprod on August 24, 2019, 06:54:35 AM
I’ve seen this in Cambridge too, what I wish Boston did instead is install a red arrow up top and not have the green/yellow ball lights work, or install straight green and yellow arrows so when the left turn phase ended the red ball could stay on.
If there was an issue with people "blocking the box", queuing of the left turn lanes, or accidents due to permissive left turns, I would have replaced the doghouse with FYA, and use TOD phasing to make the turns protected only during the rush hour and protected/permissive during the off-peak hours, Monday-Friday, similar to what New Hampshire does. Furthermore, I would change the phasing from leading to lagging left at this intersection as well.
BTW... your proposal of installing "straight green and yellow arrows so when the left-turn phase ends, the red ball could stay on" is prohibited in the 2009 MUTCD. See below:Quote from: 2009 Edition Chapter 4D. Traffic Control Signal Features, Section 4D.05 Application of Steady Signal Indications
10 The following combinations of signal indications shall not be simultaneously displayed on any one signal face:
CIRCULAR RED with CIRCULAR YELLOW;
CIRCULAR GREEN with CIRCULAR RED; or
Straight-through GREEN ARROW with CIRCULAR RED;
iPhone
I can't speak to whether the intersection in Boston mentioned needs or doesn't need protected only left turns at all times, but I can say that there is a driver expectation in most of the country (other than some of the states in the Pacific Northwest*) that a doghouse signal (or 5 phase towers) are protected/permissive and that RA-YA-GA signals are protected only. This standard should be kept, because a sign like the one in Boston seems kind of small and is very easy to overlook. If I were driving there, I probably would not notice the sign and make a left turn on green orb even without a green arrow, and I could be subject to a ticket.
Simply change the signal to RA-YA-GA if you really want left turn on arrow only. Change it to a FYA if time of day signalling is warranted.
*Jakeroot and others can confirm but in WA state (and probably a few other nearby states) left turn on red arrow is permitted onto a one-way street or a one-way freeway onramp. There is no similar rule to my knowledge in any East Coast state.
45 states permit a left turn on red from a one-way street to a one-way street, so that's not unusual. If a turn can be made on a red arrow (in either direction) is harder to pinpoint it appears, and I don't believe an accurate list has ever been made.
Title: Re: Double left turns with permissive phasing
Post by: kphoger on August 25, 2019, 03:51:19 PM
Post by: kphoger on August 25, 2019, 03:51:19 PM
Quote from: jeffandnicole on August 25, 2019, 09:15:52 AM
45 states permit a left turn on red from a one-way street to a one-way street, so that's not unusual. If a turn can be made on a red arrow (in either direction) is harder to pinpoint it appears, and I don't believe an accurate list has ever been made.
I had started working on a list a couple of years ago, but I gave up quickly because it was so time-consuming to find the states' vehicle codes one at a time.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on August 25, 2019, 06:26:33 PM
Post by: jakeroot on August 25, 2019, 06:26:33 PM
Quote from: jeffandnicole on August 25, 2019, 09:15:52 AMQuote from: mrsman on August 25, 2019, 09:02:47 AM
*Jakeroot and others can confirm but in WA state (and probably a few other nearby states) left turn on red arrow is permitted onto a one-way street or a one-way freeway onramp. There is no similar rule to my knowledge in any East Coast state.
45 states permit a left turn on red from a one-way street to a one-way street, so that's not unusual. If a turn can be made on a red arrow (in either direction) is harder to pinpoint it appears, and I don't believe an accurate list has ever been made.
Not quite the same thing. In WA (and OR, BC and MI), you can turn left onto a one-way street from both one and two way streets (RCW 46.61.055 ~3A and 3C).
This means that left turns like this (https://goo.gl/maps/RCtcC17edLg9jCK79) are legal on red (arrow or otherwise); this is very unusual compared to virtually every other state.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on August 25, 2019, 09:58:40 PM
Post by: mrsman on August 25, 2019, 09:58:40 PM
Quote from: jakeroot on August 25, 2019, 06:26:33 PMQuote from: jeffandnicole on August 25, 2019, 09:15:52 AMQuote from: mrsman on August 25, 2019, 09:02:47 AM
*Jakeroot and others can confirm but in WA state (and probably a few other nearby states) left turn on red arrow is permitted onto a one-way street or a one-way freeway onramp. There is no similar rule to my knowledge in any East Coast state.
45 states permit a left turn on red from a one-way street to a one-way street, so that's not unusual. If a turn can be made on a red arrow (in either direction) is harder to pinpoint it appears, and I don't believe an accurate list has ever been made.
Not quite the same thing. In WA (and OR, BC and MI), you can turn left onto a one-way street from both one and two way streets (RCW 46.61.055 ~3A and 3C).
This means that left turns like this (https://goo.gl/maps/RCtcC17edLg9jCK79) are legal on red (arrow or otherwise); this is very unusual compared to virtually every other state.
Correct. In the context of protected and pemissive left turns, I am necessarily discussing left turns from a two-way street, not from a one-way street.
Outside of WA, OR, and MI (where a red left arrow would not restrict you from turning left onto a one-way):
If you are on a 2-way street, the normal expectation for a permissive/protected turn is a doghouse signal or similar variant. Basically a signal face that lacks a red arrow or other clear indication to not turn. Examples are: doghouse, 5 aspect tower [i.e. a linear doghouse], 4 aspect tower [used in some lagging turns if yellow arrow would normally be displayed at the same time as yellow orb], 4 aspect towers with bimodal arrows.
If you are on a 2-way street, the normal expectation for a turn that requires you to wait for the arrow would be a signal with a red arrow. Another variant is the R-Y-GA accompanied by a sign that this is a "left turn signal" or equivalent.
The 4-aspect FYA signal is sort of a hybrid. While normally it also indicates a permissive/protected turn, that is only true during the FYA phase. During the red arrow phase, you must wait for either the green arrow or the FYA before you can turn. And in some places with TOD phasing, it may be several hours before you can make the permissive turn.
It is terrible practice to have a doghouse or any other signal face that is normally permissive/protected used for a protective only signal. And on top of that, the sign in Boston is quite small and hard to see.
For those in WA, OR, and MI, the same holds true as well with an added proviso. Since the red arrow does not restrict the turn onto a one-way street, if the DOT in those states wanted to make the intersection a left turn on green arrow situation, the only possible way to do so is with a sign. The hope is that they pick a big enough sign. The other 47 states (including MA and IL) don't have this problem. Use a red arrow signal and don't force us to read signs that defy normal expectations.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on September 02, 2019, 06:51:01 PM
Post by: fwydriver405 on September 02, 2019, 06:51:01 PM
Quote from: mrsman on August 25, 2019, 09:09:57 AMQuote from: kphoger on August 24, 2019, 06:18:47 PMQuote from: mrsman on August 22, 2019, 09:25:29 PM
Give NYC some credit - Chicago would make a 5 signal display into protected only by sign (as done on Michigan Ave).
I was driving down Kellogg the other day and thought of you because of this sign (https://goo.gl/maps/jp36Nuo9rirbdPhx9).
WHile the construction makes the signal placement ugly, this sign is not nearly as bad as the Chicago or Boston examples. It seems pretty clear that the left signal controls left turns and the other two signals control straight. Seeing the red ball (especially while the other signals are green) would lead me to at least suspect that the left signal controls left turns.
While the latest MUTCD recommends (or requires, not sure how to actually interpret it) that new exclusive left turn signals have red arrows instead of red balls, there are plenty of signals out there that are R-Y-GA that control a protected only left turn. They are still very common in PA and VA which use the sign "Left turn signal". This was also the standard for a while in CA, where they had a sign that read "Left turn on arrow only" (the only arrow was a green one), but in that case the left turn signal was in a 3M or louvered so as not to confuse nearby straight traffic. Very few of those remain in CA as most have been converted to red arrow.
Today while travelling from UMaine Orono to Bangor, I found this strange signal configuration downtown:
Main St and Route 222 (https://www.google.com/maps/@44.7986892,-68.7726594,3a,15y,357.18h,96.55t/data=!3m6!1e1!3m4!1sB2-zKy_N4bcmPxAicDlMgQ!2e0!7i16384!8i8192)
Setup as a lead-lag signal, the leading side only allows turns on the green arrow, and the lagging side allows permissive-protected turns. This is a close example that Amtrakprod mentioned with the straight arrows:
QuoteQuote from: Amtrakprod on August 24, 2019, 06:54:35 AM
I've seen this in Cambridge too, what I wish Boston did instead is install a red arrow up top and not have the green/yellow ball lights work, or install straight green and yellow arrows so when the left turn phase ended the red ball could stay on.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on September 02, 2019, 10:35:10 PM
Post by: mrsman on September 02, 2019, 10:35:10 PM
Quote from: fwydriver405 on September 02, 2019, 06:51:01 PMQuote from: mrsman on August 25, 2019, 09:09:57 AMQuote from: kphoger on August 24, 2019, 06:18:47 PMQuote from: mrsman on August 22, 2019, 09:25:29 PM
Give NYC some credit - Chicago would make a 5 signal display into protected only by sign (as done on Michigan Ave).
I was driving down Kellogg the other day and thought of you because of this sign (https://goo.gl/maps/jp36Nuo9rirbdPhx9).
WHile the construction makes the signal placement ugly, this sign is not nearly as bad as the Chicago or Boston examples. It seems pretty clear that the left signal controls left turns and the other two signals control straight. Seeing the red ball (especially while the other signals are green) would lead me to at least suspect that the left signal controls left turns.
While the latest MUTCD recommends (or requires, not sure how to actually interpret it) that new exclusive left turn signals have red arrows instead of red balls, there are plenty of signals out there that are R-Y-GA that control a protected only left turn. They are still very common in PA and VA which use the sign "Left turn signal". This was also the standard for a while in CA, where they had a sign that read "Left turn on arrow only" (the only arrow was a green one), but in that case the left turn signal was in a 3M or louvered so as not to confuse nearby straight traffic. Very few of those remain in CA as most have been converted to red arrow.
Today while travelling from UMaine Orono to Bangor, I found this strange signal configuration downtown:
Main St and Route 222 (https://www.google.com/maps/@44.7986892,-68.7726594,3a,15y,357.18h,96.55t/data=!3m6!1e1!3m4!1sB2-zKy_N4bcmPxAicDlMgQ!2e0!7i16384!8i8192)
Setup as a lead-lag signal, the leading side only allows turns on the green arrow, and the lagging side allows permissive-protected turns. This is a close example that Amtrakprod mentioned with the straight arrows:QuoteQuote from: Amtrakprod on August 24, 2019, 06:54:35 AM
I've seen this in Cambridge too, what I wish Boston did instead is install a red arrow up top and not have the green/yellow ball lights work, or install straight green and yellow arrows so when the left turn phase ended the red ball could stay on.
Without employing FYAs, the leading side of a lead-lag signal must be left turn on arrow only in order to avoid yellow trap. The problem here is that the signal is irregular and if you don't see the sign, you may end up having an accident as you expect the oncoming traffic to begin to stop as you see yellow.
And you really have to be careful how to read the sign too. When doghouses first came on the scene in Los Angeles, the vast majority of them had no sign whatsoever. I imagine the DOT believed that it was understood that if there was no sign saying otherwise, left turns were permitted on green orb. Well, at many of those intersections, people would just wait regardless, so they started putting up (in some places, not all) "Left turn yield on green." The problem with this is that now you have to read very carefully to determine if you are allowed to go on green or "left turn on green arrow only." At an intersection, there is so much to think about that the subtleties between these two signs, which mean opposite things, can easily be missed.
It is far better to have a clear rule. No left turn on red arrow. If there is no red arrow, you may turn left on green ball if you yield to opposing traffic.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on September 03, 2019, 08:27:25 AM
Post by: fwydriver405 on September 03, 2019, 08:27:25 AM
Quote from: mrsman on September 02, 2019, 10:35:10 PM
Without employing FYAs, the leading side of a lead-lag signal must be left turn on arrow only in order to avoid yellow trap. The problem here is that the signal is irregular and if you don't see the sign, you may end up having an accident as you expect the oncoming traffic to begin to stop as you see yellow.
The only major problem with not employing FYA in your example is that yellow trap can still occur on the lagging side if phase skip were to recall the leading left turn phase.
When our new high school opened on 11 Oct 2018 (the intersection wasn't signalised until sometime in February 2019), the signal had to be reprogrammed last-minute with anti-backup logic to prevent phase 1 (protected only) from yellow trapping phase 2 (5-section PPLT) on northbound Main St as pictured below:
(https://i.ibb.co/b6r7CV4/Screenshot-2019-09-03-at-08-16-48.png) (https://ibb.co/p13nMTH)
Once FYA's are retrofitted into this intersection (https://www.google.com/maps/@43.419976,-70.7565294,3a,75y,320.25h,89.38t/data=!3m6!1e1!3m4!1sHoOSAJv5feucDOkRBwvnKA!2e0!7i13312!8i6656) in 2021, then the normal phase skip is OK as then the yellow trap would be removed by continually flashing the yellow arrow when the oncoming green on Main St has a green light for the southbound thru traffic.
Title: Re: Double left turns with permissive phasing
Post by: MNHighwayMan on September 05, 2019, 08:39:12 AM
Post by: MNHighwayMan on September 05, 2019, 08:39:12 AM
Quote from: jakeroot on September 05, 2019, 01:29:09 AM
Having put on a plentiful number of miles in WA, OR, and BC (all places where the maneuver is legal), I have seen perhaps 10 or 15 people ever take advantage of it. I highly doubt ODOT specifically times their left turns to encourage this. I think they know as well as I do that people rarely actually turn left on red from a two-way to one-way. Problem is, all three places are full of people from places where the maneuver is not legal. Obviously they aren't aware of our laws. What would be nice, is if more places used these types of signs (https://goo.gl/maps/uFz6yW9JTL9Q41j86), commonly used by Seattle DOT. Then you get people to actually do the (https://goo.gl/maps/pq4Wu6CEAnSr66nb6) maneuver (https://goo.gl/maps/vVthBumQYomq8tLu6)
Seems to me they should use a flashing red arrow, where left on red is permitted, instead of a solid red arrow plus (maybe) a sign.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on September 05, 2019, 03:03:20 PM
Post by: jakeroot on September 05, 2019, 03:03:20 PM
Quote from: MNHighwayMan on September 05, 2019, 08:39:12 AMQuote from: jakeroot on September 05, 2019, 01:29:09 AM
Having put on a plentiful number of miles in WA, OR, and BC (all places where the maneuver is legal), I have seen perhaps 10 or 15 people ever take advantage of it. I highly doubt ODOT specifically times their left turns to encourage this. I think they know as well as I do that people rarely actually turn left on red from a two-way to one-way. Problem is, all three places are full of people from places where the maneuver is not legal. Obviously they aren't aware of our laws. What would be nice, is if more places used these types of signs (https://goo.gl/maps/uFz6yW9JTL9Q41j86), commonly used by Seattle DOT. Then you get people to actually do the (https://goo.gl/maps/pq4Wu6CEAnSr66nb6) maneuver (https://goo.gl/maps/vVthBumQYomq8tLu6)
Seems to me they should use a flashing red arrow, where left on red is permitted, instead of a solid red arrow plus (maybe) a sign.
The problem, as far as I know, is that all three places, at the top-level (provincial/state), do not allow any sort of permissive left turn with more than one lane. All three have examples, but they're all city installs. Now, technically, all sanction such maneuvers by allowing these left turns on red (though I have seen signs (https://goo.gl/maps/5Sw2aymB7kkr6XP37) disallowing the turn where it would be obvious in other states that it would not be allowed), but they apparently don't want to come out and just make the maneuver obvious with flashing red arrows. I guess that would be too forward? They leave it up to people to read the relevant statutes!
Title: Re: Double left turns with permissive phasing
Post by: mrsman on September 06, 2019, 05:07:56 PM
Post by: mrsman on September 06, 2019, 05:07:56 PM
Quote from: MNHighwayMan on September 05, 2019, 08:39:12 AMQuote from: jakeroot on September 05, 2019, 01:29:09 AM
Having put on a plentiful number of miles in WA, OR, and BC (all places where the maneuver is legal), I have seen perhaps 10 or 15 people ever take advantage of it. I highly doubt ODOT specifically times their left turns to encourage this. I think they know as well as I do that people rarely actually turn left on red from a two-way to one-way. Problem is, all three places are full of people from places where the maneuver is not legal. Obviously they aren't aware of our laws. What would be nice, is if more places used these types of signs (https://goo.gl/maps/uFz6yW9JTL9Q41j86), commonly used by Seattle DOT. Then you get people to actually do the (https://goo.gl/maps/pq4Wu6CEAnSr66nb6) maneuver (https://goo.gl/maps/vVthBumQYomq8tLu6)
Seems to me they should use a flashing red arrow, where left on red is permitted, instead of a solid red arrow plus (maybe) a sign.
I would strongly prefer this approach as well, as it would be more consistent with the rules of the other 47 states.
Here's a qn for Jake (or anyone else really familiar with WA/OR/BC rules), let's say you have the intersection of a 2-way street with a 1-way street. (Not at a T-intersection) And let's say that the left turn is controlled by a RA-YA-GA signal. This would mean that you should be able to make a permissive turn at all times, assuming you first come to a complete stop if you see a RA. (Obviously, the turn is protected with a green arrow.)
Is there any way for you to know, while you see the RA, whether you have to yield to opposing traffic or whether you have to yield to the traffic on the one-way street that is coming from your right? And what about when the traffic signal changes, is there an obvious point in time when you are aware that you have to change your yield from side street to opposing traffic (and vice versa).
I've always heard that the justification for this move is that it is not any different from a LTOR from one-way to one-way, permitted in a majority of states. (And in that case, IMO correctly, the states contend that LTOR one-way to one-way is equivalent to RTOR and generally safe.) But it seems like the need to contend with opposing traffic makes this, left from a 2-way to 1-way on red, a far riskier move.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on September 06, 2019, 05:45:20 PM
Post by: mrsman on September 06, 2019, 05:45:20 PM
Quote from: fwydriver405 on September 03, 2019, 08:27:25 AMQuote from: mrsman on September 02, 2019, 10:35:10 PM
Without employing FYAs, the leading side of a lead-lag signal must be left turn on arrow only in order to avoid yellow trap. The problem here is that the signal is irregular and if you don't see the sign, you may end up having an accident as you expect the oncoming traffic to begin to stop as you see yellow.
The only major problem with not employing FYA in your example is that yellow trap can still occur on the lagging side if phase skip were to recall the leading left turn phase.
When our new high school opened on 11 Oct 2018 (the intersection wasn't signalised until sometime in February 2019), the signal had to be reprogrammed last-minute with anti-backup logic to prevent phase 1 (protected only) from yellow trapping phase 2 (5-section PPLT) on northbound Main St as pictured below:
(https://i.ibb.co/b6r7CV4/Screenshot-2019-09-03-at-08-16-48.png) (https://ibb.co/p13nMTH)
Once FYA's are retrofitted into this intersection (https://www.google.com/maps/@43.419976,-70.7565294,3a,75y,320.25h,89.38t/data=!3m6!1e1!3m4!1sHoOSAJv5feucDOkRBwvnKA!2e0!7i13312!8i6656) in 2021, then the normal phase skip is OK as then the yellow trap would be removed by continually flashing the yellow arrow when the oncoming green on Main St has a green light for the southbound thru traffic.
I'm sorry that I'm missing something in your explanation. I'm not trained in TE, but obviously somewhat interested based on my posts on this forum. (I don't really understand the timing diagram.)
In my example, the normal phases are:
1. Eastbound straight and left (leading phase)
2. E & W straight, EB left prohibited by red arrow, WB left permissive on green orb.
3. Westbound straight and left (lagging phase)
4. N-S traffic on side street.
Now, from what I understand, the phase skip that you are suggesting is that at the conclusion of phase 3, phase 4 is skipped so now we are back at phase 1. If phase 3 properly closes with a yellow ball and then a red, I don't see a yellow trap problem. To allow the eastbound left, you have to prohibit the westbound straight.
If both phases 4 and 1 are skipped, then in some ways phase 3 acts like a leading left as well. You don't get a yellow arrow with a classic RYG-GA signal that was commonplace for lagging lefts, but that is still not yellow trap as those cars will now yield to opposing traffic, since the green arrow vanished.
So I guess you must mean the possibility that you are at phase 2, and phase 3 and phase 4 are skipped so you head back to phase 1. The westbound side gets yellow and red, but not the eastbound side. This is a yellow trap, since counter-intuitively phase 1 acts as a lagging phase due to the skipping of both phases 3 and 4. So as you correctly note, if both phases 3 and 4 are skipped, you must properly end phase 2 with a quick yellow and red, before allowing for phase 1 to come again.
To be honest, I have never seen that in practice. Since phase 3 allows for left turn filtering, from what i have seen it will usually be programmed for the busier left turn and will rarely get skipped.
Here is an intersection that years ago had lead-lag phasing, with protected only lead and PPLT lag. (Now both directions have protected only turns.)
Sunset at Hilgard - Copa de Oro in Los Angeles, right outside the UCLA campus.
https://www.google.com/maps/@34.0782706,-118.4393688,3a,75y,240.33h,78.77t/data=!3m7!1e1!3m5!1sWkNR_wJMf61DMNamoaADsQ!2e0!6s%2F%2Fgeo1.ggpht.com%2Fcbk%3Fpanoid%3DWkNR_wJMf61DMNamoaADsQ%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D12.513728%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192
In this example, years ago, the EB left from Sunset to Copa was leading protected only. Copa is a very minor street and got very little traffic. The WB left from Sunset to Hilgard was really major as it was a key way for traffic on Sunset (a major street in L.A.) to reach several entrances to the UCLA campus (closer to the main buildings of campus) and Westwood Village. The main bus on Sunset also made this turn, for this reason. I could never fathom the possibility that the left turn to Hilgard would ever be skipped at any cycle [phase 3], as well as the phase for Hilgard itself [phase 4] in order to service the left turn at Copa [phase 1]. I have no idea if there was ever any phase skipping precautions made here [doubt it], but it was simply unnecessary as a practical matter.
I guess the signal that in your town is different, and of course proper signaling is always important.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on September 06, 2019, 06:39:08 PM
Post by: jakeroot on September 06, 2019, 06:39:08 PM
Quote from: mrsman on September 06, 2019, 05:07:56 PMQuote from: MNHighwayMan on September 05, 2019, 08:39:12 AMQuote from: jakeroot on September 05, 2019, 01:29:09 AM
Having put on a plentiful number of miles in WA, OR, and BC (all places where the maneuver is legal), I have seen perhaps 10 or 15 people ever take advantage of it. I highly doubt ODOT specifically times their left turns to encourage this. I think they know as well as I do that people rarely actually turn left on red from a two-way to one-way. Problem is, all three places are full of people from places where the maneuver is not legal. Obviously they aren't aware of our laws. What would be nice, is if more places used these types of signs (https://goo.gl/maps/uFz6yW9JTL9Q41j86), commonly used by Seattle DOT. Then you get people to actually do the (https://goo.gl/maps/pq4Wu6CEAnSr66nb6) maneuver (https://goo.gl/maps/vVthBumQYomq8tLu6)
Seems to me they should use a flashing red arrow, where left on red is permitted, instead of a solid red arrow plus (maybe) a sign.
I would strongly prefer this approach as well, as it would be more consistent with the rules of the other 47 states.
Here's a qn for Jake (or anyone else really familiar with WA/OR/BC rules), let's say you have the intersection of a 2-way street with a 1-way street. (Not at a T-intersection) And let's say that the left turn is controlled by a RA-YA-GA signal. This would mean that you should be able to make a permissive turn at all times, assuming you first come to a complete stop if you see a RA. (Obviously, the turn is protected with a green arrow.)
Is there any way for you to know, while you see the RA, whether you have to yield to opposing traffic or whether you have to yield to the traffic on the one-way street that is coming from your right? And what about when the traffic signal changes, is there an obvious point in time when you are aware that you have to change your yield from side street to opposing traffic (and vice versa).
I've always heard that the justification for this move is that it is not any different from a LTOR from one-way to one-way, permitted in a majority of states. (And in that case, IMO correctly, the states contend that LTOR one-way to one-way is equivalent to RTOR and generally safe.) But it seems like the need to contend with opposing traffic makes this, left from a 2-way to 1-way on red, a far riskier move.
For these kinds of maneuvers, you have to rely on the parallel through movement to know exactly who you'll be contending with. At left turns onto on-ramps for interchanges such as Parclo B4's, there is no off-ramp to look for, so you stop on red and then proceed when safe. At left turns where there is a one-way street coming up to, and continuing through the intersection, if the through light is red, you have to watch for traffic from the right. Because there would be no oncoming left turn at 99% of these intersections, seeing all-red would only be an indication that traffic from the right has a green, not that the oncoming traffic has an advanced left or something.
As liberal as I am when it comes to this law, I will almost always wait for the parallel through traffic to get their green before creeping forward and turning on red. It's very awkward when there's a double left turn and (something like) three through lanes, and suddenly you just barge into the intersection and turn. Legal? Yes. Uncomfortable for almost everyone? Definitely.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on September 07, 2019, 11:05:17 PM
Post by: mrsman on September 07, 2019, 11:05:17 PM
Quote from: jakeroot on September 06, 2019, 06:39:08 PMQuote from: mrsman on September 06, 2019, 05:07:56 PMQuote from: MNHighwayMan on September 05, 2019, 08:39:12 AMQuote from: jakeroot on September 05, 2019, 01:29:09 AM
Having put on a plentiful number of miles in WA, OR, and BC (all places where the maneuver is legal), I have seen perhaps 10 or 15 people ever take advantage of it. I highly doubt ODOT specifically times their left turns to encourage this. I think they know as well as I do that people rarely actually turn left on red from a two-way to one-way. Problem is, all three places are full of people from places where the maneuver is not legal. Obviously they aren't aware of our laws. What would be nice, is if more places used these types of signs (https://goo.gl/maps/uFz6yW9JTL9Q41j86), commonly used by Seattle DOT. Then you get people to actually do the (https://goo.gl/maps/pq4Wu6CEAnSr66nb6) maneuver (https://goo.gl/maps/vVthBumQYomq8tLu6)
Seems to me they should use a flashing red arrow, where left on red is permitted, instead of a solid red arrow plus (maybe) a sign.
I would strongly prefer this approach as well, as it would be more consistent with the rules of the other 47 states.
Here's a qn for Jake (or anyone else really familiar with WA/OR/BC rules), let's say you have the intersection of a 2-way street with a 1-way street. (Not at a T-intersection) And let's say that the left turn is controlled by a RA-YA-GA signal. This would mean that you should be able to make a permissive turn at all times, assuming you first come to a complete stop if you see a RA. (Obviously, the turn is protected with a green arrow.)
Is there any way for you to know, while you see the RA, whether you have to yield to opposing traffic or whether you have to yield to the traffic on the one-way street that is coming from your right? And what about when the traffic signal changes, is there an obvious point in time when you are aware that you have to change your yield from side street to opposing traffic (and vice versa).
I've always heard that the justification for this move is that it is not any different from a LTOR from one-way to one-way, permitted in a majority of states. (And in that case, IMO correctly, the states contend that LTOR one-way to one-way is equivalent to RTOR and generally safe.) But it seems like the need to contend with opposing traffic makes this, left from a 2-way to 1-way on red, a far riskier move.
For these kinds of maneuvers, you have to rely on the parallel through movement to know exactly who you'll be contending with. At left turns onto on-ramps for interchanges such as Parclo B4's, there is no off-ramp to look for, so you stop on red and then proceed when safe. At left turns where there is a one-way street coming up to, and continuing through the intersection, if the through light is red, you have to watch for traffic from the right. Because there would be no oncoming left turn at 99% of these intersections, seeing all-red would only be an indication that traffic from the right has a green, not that the oncoming traffic has an advanced left or something.
As liberal as I am when it comes to this law, I will almost always wait for the parallel through traffic to get their green before creeping forward and turning on red. It's very awkward when there's a double left turn and (something like) three through lanes, and suddenly you just barge into the intersection and turn. Legal? Yes. Uncomfortable for almost everyone? Definitely.
It seems to me that the origins of the left turn law in WA/OR/BC was as it applied in a very simple intersection. No left turn arrows. Essentially 2-phase traffic signals, N-S and E-W. Obviously, in a simple situation like that, you know very well who has the ROW. But in the more modern signals with multiple phases, it can be downright complicated. Yet the law hasn't been updated.
Title: Re: Double left turns with permissive phasing
Post by: US 89 on September 08, 2019, 07:11:41 PM
Post by: US 89 on September 08, 2019, 07:11:41 PM
I think the WA/OR/BC left turn law creates more problems than it solves. Left on red from a one-way to another one-way makes sense, but when you add oncoming traffic to the mix it throws in a whole other set of issues and potential for accidents.
That being said, surely the DOTs in those areas know it's unique and the vast majority of other states/provinces don't have that. If they think it's safe and would help improve traffic flow, it'd be in their best interests to put up a sign at each intersection where this is a legal movement, so everyone would take advantage of the law and maximize traffic efficiency.
The thing that really throws me about it is that you're allowed to turn left on a red arrow. That to me is nuts, because when I learned to drive in Utah, a red arrow was taken as an explicit prohibition of that movement. In fact, in that state it is illegal to turn right on a red arrow. But to avoid problems with drivers from states where that movement is legal, almost every intersection with a red right arrow has a supplemental "no turn on red" sign.
That being said, surely the DOTs in those areas know it's unique and the vast majority of other states/provinces don't have that. If they think it's safe and would help improve traffic flow, it'd be in their best interests to put up a sign at each intersection where this is a legal movement, so everyone would take advantage of the law and maximize traffic efficiency.
The thing that really throws me about it is that you're allowed to turn left on a red arrow. That to me is nuts, because when I learned to drive in Utah, a red arrow was taken as an explicit prohibition of that movement. In fact, in that state it is illegal to turn right on a red arrow. But to avoid problems with drivers from states where that movement is legal, almost every intersection with a red right arrow has a supplemental "no turn on red" sign.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on September 11, 2019, 08:15:47 PM
Post by: mrsman on September 11, 2019, 08:15:47 PM
Quote from: jakeroot on September 06, 2019, 06:39:08 PMSo you say that's one way of keeping track of when doing you left turn from a two way to a one way is by glancing at the through signal and letting that determine how you approached the intersection. In my mind that is very counterintuitive. Especially in the era of the fya, especially when they are used to prevent a yellow trap, we are taught that when making a left turn you need to focus solely on the left turn signal and ignore what the thru signal is doing. To the extent that this is not being done, we have already discussed in the perceived yellow track threads.Quote from: mrsman on September 06, 2019, 05:07:56 PMQuote from: MNHighwayMan on September 05, 2019, 08:39:12 AMQuote from: jakeroot on September 05, 2019, 01:29:09 AM
Having put on a plentiful number of miles in WA, OR, and BC (all places where the maneuver is legal), I have seen perhaps 10 or 15 people ever take advantage of it. I highly doubt ODOT specifically times their left turns to encourage this. I think they know as well as I do that people rarely actually turn left on red from a two-way to one-way. Problem is, all three places are full of people from places where the maneuver is not legal. Obviously they aren't aware of our laws. What would be nice, is if more places used these types of signs (https://goo.gl/maps/uFz6yW9JTL9Q41j86), commonly used by Seattle DOT. Then you get people to actually do the (https://goo.gl/maps/pq4Wu6CEAnSr66nb6) maneuver (https://goo.gl/maps/vVthBumQYomq8tLu6)
Seems to me they should use a flashing red arrow, where left on red is permitted, instead of a solid red arrow plus (maybe) a sign.
I would strongly prefer this approach as well, as it would be more consistent with the rules of the other 47 states.
Here's a qn for Jake (or anyone else really familiar with WA/OR/BC rules), let's say you have the intersection of a 2-way street with a 1-way street. (Not at a T-intersection) And let's say that the left turn is controlled by a RA-YA-GA signal. This would mean that you should be able to make a permissive turn at all times, assuming you first come to a complete stop if you see a RA. (Obviously, the turn is protected with a green arrow.)
Is there any way for you to know, while you see the RA, whether you have to yield to opposing traffic or whether you have to yield to the traffic on the one-way street that is coming from your right? And what about when the traffic signal changes, is there an obvious point in time when you are aware that you have to change your yield from side street to opposing traffic (and vice versa).
I've always heard that the justification for this move is that it is not any different from a LTOR from one-way to one-way, permitted in a majority of states. (And in that case, IMO correctly, the states contend that LTOR one-way to one-way is equivalent to RTOR and generally safe.) But it seems like the need to contend with opposing traffic makes this, left from a 2-way to 1-way on red, a far riskier move.
For these kinds of maneuvers, you have to rely on the parallel through movement to know exactly who you'll be contending with. At left turns onto on-ramps for interchanges such as Parclo B4's, there is no off-ramp to look for, so you stop on red and then proceed when safe. At left turns where there is a one-way street coming up to, and continuing through the intersection, if the through light is red, you have to watch for traffic from the right. Because there would be no oncoming left turn at 99% of these intersections, seeing all-red would only be an indication that traffic from the right has a green, not that the oncoming traffic has an advanced left or something.
As liberal as I am when it comes to this law, I will almost always wait for the parallel through traffic to get their green before creeping forward and turning on red. It's very awkward when there's a double left turn and (something like) three through lanes, and suddenly you just barge into the intersection and turn. Legal? Yes. Uncomfortable for almost everyone? Definitely.
Nexus 5X
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on September 11, 2019, 11:06:02 PM
Post by: jakeroot on September 11, 2019, 11:06:02 PM
Quote from: mrsman on September 11, 2019, 08:15:47 PM
So you say that's one way of keeping track of when doing you left turn from a two way to a one way is by glancing at the through signal and letting that determine how you approached the intersection. In my mind that is very counterintuitive. Especially in the era of the fya, especially when they are used to prevent a yellow trap, we are taught that when making a left turn you need to focus solely on the left turn signal and ignore what the thru signal is doing. To the extent that this is not being done, we have already discussed in the perceived yellow track threads.
It's acceptable to rely on the parallel through traffic in this instance, because there is no oncoming left turn that may preemptively end the parallel through phase. The next time they get a red, would be the next time that I also would need to finish my turn.
If you look at the video I made about this maneuver, you can see (at 0:46 when I first arrive at the left turn) that the parallel traffic has a red light. Because the cross-traffic is one-way, I know that it can't be red because of an oncoming left turn. I can also see traffic coming off the freeway from my right. Turning through a gap here might be unwise, so I wait for them to receive a red light. Because the double left here is lagging, the through traffic gets to go next, while the left turn onto the freeway must wait. Again, because there is no oncoming left turn, I need not be worried about the parallel through traffic receiving a red light while I'm waiting. Though to the point that it matters, I'm still legally allowed to turn on red, even if they somehow ended up with a red light. Not that that would make much sense.
In this video, however, I do make a left turn on red while the parallel traffic also has a red light. This situation is relatively uncommon, and I find it more acceptable when traffic is quiet. Skip to 0:27:
https://youtu.be/2Qa7vD0_TkY?t=46
Title: Re: Double left turns with permissive phasing
Post by: mrsman on September 13, 2019, 05:18:48 PM
Post by: mrsman on September 13, 2019, 05:18:48 PM
Quote from: jakeroot on September 11, 2019, 11:06:02 PMQuote from: mrsman on September 11, 2019, 08:15:47 PM
So you say that's one way of keeping track of when doing you left turn from a two way to a one way is by glancing at the through signal and letting that determine how you approached the intersection. In my mind that is very counterintuitive. Especially in the era of the fya, especially when they are used to prevent a yellow trap, we are taught that when making a left turn you need to focus solely on the left turn signal and ignore what the thru signal is doing. To the extent that this is not being done, we have already discussed in the perceived yellow track threads.
It's acceptable to rely on the parallel through traffic in this instance, because there is no oncoming left turn that may preemptively end the parallel through phase. The next time they get a red, would be the next time that I also would need to finish my turn.
If you look at the video I made about this maneuver, you can see (at 0:46 when I first arrive at the left turn) that the parallel traffic has a red light. Because the cross-traffic is one-way, I know that it can't be red because of an oncoming left turn. I can also see traffic coming off the freeway from my right. Turning through a gap here might be unwise, so I wait for them to receive a red light. Because the double left here is lagging, the through traffic gets to go next, while the left turn onto the freeway must wait. Again, because there is no oncoming left turn, I need not be worried about the parallel through traffic receiving a red light while I'm waiting. Though to the point that it matters, I'm still legally allowed to turn on red, even if they somehow ended up with a red light. Not that that would make much sense.
In this video, however, I do make a left turn on red while the parallel traffic also has a red light. This situation is relatively uncommon, and I find it more acceptable when traffic is quiet. Skip to 0:27:
https://youtu.be/2Qa7vD0_TkY?t=46
Regarding the left turn at 0:46, even though under WA law you are allowed to make the left turn while cross traffic has green, you decide against turning during a possible short gap, due to safety concerns. So then, you do make the left turn when oncoming traffic has a green and you are able to turn during a gap. So practically speaking, this is no different than making any permissive left, yielding to opposing traffic [as opposed to cross traffic].
What really bothers me a lot about some of this is that the same signal means different things, based on the situation. It seems to ask the driver a lot to keep track of.
If I see a red left arrow crossing a two-way street, this is a protected only turn and I must wait for green arrow. This is of course the rule in the majority of other states in all circumstances.
If I see a red left arrow crossing a one-way street, I can turn anytime I want, so long as I yield appropriately. If I see a red orb nearby, that likely means that I will have to yield to cross traffic and can turn in a gap of traffic, but that is likely unsafe when it's busy. if I see a green orb nearby, this is equivalent to a normal permissive turn and I turn during a gap in opposing traffic. [IMO, this would be so much more improved with a flashing red arrow, but of course I don't dictate WA law.]
If I see a red left arrow crossing a one-way street, that happens to be two-way in the other direction. (I.e. I'm driving northbound, the cross street is one-way westbound leaving the intersection, but two-way east of the intersection.) If I see a red orb nearby, that likely means that I will have to yield to cross traffic and can turn in a gap of traffic, but that is likely unsafe when it's busy. But it could also possibly mean that opposing traffic has green and an opposing protected left to serve the two-way street.* This is really problematic. However, if I see a green orb nearby, this is equivalent to a normal permissive turn and I turn during a gap in opposing traffic, as in the case above.
If I see a red left arrow crossing a one-way street, that happens to be one-way in the other direction. (I.e. I'm driving northbound, the cross street is one-way westbound leaving the intersection to the west, and also one-way eastbound leaving the intersection to the east.) In essence, there is no cross-traffic, other than pedestrians. If I see a red orb nearby, that likely means that I will have to yield to cross traffic pedestrians and can turn. Other than the pedestrians, this is equivalent to a protected turn, since opposing traffic is stopped. But it could also possibly mean that opposing traffic has green and an opposing protected left to serve the two-way street. But it could also possibly mean that opposing traffic has green and an opposing protected left to serve the opposite direction one-way street.* This is also problematic. However, if I see a green orb nearby, this is equivalent to a normal permissive turn and I turn during a gap in opposing traffic, as in the case above.
* The two opposing left turns may not necessarily have green arrows at the same time. If they do, then this problem is largely eliminated, but at the expense of wasted green time.
Title: Re: Double left turns with permissive phasing
Post by: MNHighwayMan on September 13, 2019, 06:04:21 PM
Post by: MNHighwayMan on September 13, 2019, 06:04:21 PM
Quote from: mrsman on September 13, 2019, 05:18:48 PM
What really bothers me a lot about some of this is that the same signal means different things, based on the situation. It seems to ask the driver a lot to keep track of.
If I see a red left arrow crossing a two-way street, this is a protected only turn and I must wait for green arrow. This is of course the rule in the majority of other states in all circumstances.
These are two of the big reasons I don't like this Pacific Red Arrow law. (PRA for short, I'll call it from now on.) Consistency with traffic laws is key, and I'd call the PRA very inconsistent with both other states and with itself, for varying depending on the situation.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on September 15, 2019, 01:03:33 AM
Post by: mrsman on September 15, 2019, 01:03:33 AM
Quote from: MNHighwayMan on September 13, 2019, 06:04:21 PMQuote from: mrsman on September 13, 2019, 05:18:48 PM
What really bothers me a lot about some of this is that the same signal means different things, based on the situation. It seems to ask the driver a lot to keep track of.
If I see a red left arrow crossing a two-way street, this is a protected only turn and I must wait for green arrow. This is of course the rule in the majority of other states in all circumstances.
These are two of the big reasons I don't like this Pacific Red Arrow law. (PRA for short, I'll call it from now on.) Consistency with traffic laws is key, and I'd call the PRA very inconsistent with both other states and with itself, for varying depending on the situation.
The Pac NW Red arrow law also applies to red orbs. Left turn from 2-way to 1-way, is basically permitted at all times.
I believe that the basic driving laws should be uniform across all 50 states. There is a lot of confusion out there, and because we live in such a free country it is very easy for people to drive from state to state without restriction.
There is no reason why if a local DOT feels that a certain intersection should be stop and then make a turn, that a red arrow couldn't be replaced with a flashing red arrow. Any intersection that should be an exception can be signed as such, but that should be rare because the expectation is that a red arrow is stop until green arrow, a flashing red arrow is stop and then proceed when safe, and no arrow would allow a permissive turn (and no need to wait for a green arrow).
I will say that making a left turn from a 2-way to a 1-way at a T intersection (where the 1-way ends at the 2-way) would seem to be a safe turn on a red orb, even though it is prohibited in most states. It's basically a protected left, except for possible pedestrian interaction. It can be permitted by sign. Here's an example from a relatively remote part of NYC (which generally doesn't even allow RTOR) to allow LTOR from 2-way to 1-way at a T-intersection.
https://www.google.com/maps/@40.6096868,-73.8190742,3a,75y,193.71h,88.53t/data=!3m6!1e1!3m4!1sKnloxMvHK6TsGqbAqOvusQ!2e0!7i16384!8i8192
So I have no problem allowing the turn in that circumstance, just add a sign.
Title: Re: Double left turns with permissive phasing
Post by: roadfro on September 15, 2019, 12:13:20 PM
Post by: roadfro on September 15, 2019, 12:13:20 PM
Quote from: mrsman on September 15, 2019, 01:03:33 AM
Here's an example from a relatively remote part of NYC (which generally doesn't even allow RTOR) to allow LTOR from 2-way to 1-way at a T-intersection.
https://www.google.com/maps/@40.6096868,-73.8190742,3a,75y,193.71h,88.53t/data=!3m6!1e1!3m4!1sKnloxMvHK6TsGqbAqOvusQ!2e0!7i16384!8i8192
Looking around that intersection, I'm confused. I see the one way sign for the side street indicating it's one way away from this intersection. But why are there vehicular signals facing the side street and a stop bar on the side street? Was the side street formerly two way?
Title: Re: Double left turns with permissive phasing
Post by: MNHighwayMan on September 15, 2019, 12:55:14 PM
Post by: MNHighwayMan on September 15, 2019, 12:55:14 PM
Quote from: roadfro on September 15, 2019, 12:13:20 PMQuote from: mrsman on September 15, 2019, 01:03:33 AMLooking around that intersection, I'm confused. I see the one way sign for the side street indicating it's one way away from this intersection. But why are there vehicular signals facing the side street and a stop bar on the side street? Was the side street formerly two way?
Here's an example from a relatively remote part of NYC (which generally doesn't even allow RTOR) to allow LTOR from 2-way to 1-way at a T-intersection.
https://www.google.com/maps/@40.6096868,-73.8190742,3a,75y,193.71h,88.53t/data=!3m6!1e1!3m4!1sKnloxMvHK6TsGqbAqOvusQ!2e0!7i16384!8i8192
It's also possible that those were formerly used as pedestrian signals before there were dedicated pedestrian signal heads installed there.
Edit to add: If you go back to the 2013 GSV imagery (https://www.google.com/maps/@40.6096222,-73.8189278,3a,75y,145.3h,84.77t/data=!3m6!1e1!3m4!1sIKLnXzv3NghKoWMQVByGGg!2e0!7i13312!8i6656), there isn't a stop line painted there. I think that might be a relatively recent addition, added in error.
Title: Re: Double left turns with permissive phasing
Post by: roadfro on September 15, 2019, 02:18:17 PM
Post by: roadfro on September 15, 2019, 02:18:17 PM
Quote from: MNHighwayMan on September 15, 2019, 12:55:14 PMQuote from: roadfro on September 15, 2019, 12:13:20 PMQuote from: mrsman on September 15, 2019, 01:03:33 AMLooking around that intersection, I'm confused. I see the one way sign for the side street indicating it's one way away from this intersection. But why are there vehicular signals facing the side street and a stop bar on the side street? Was the side street formerly two way?
Here's an example from a relatively remote part of NYC (which generally doesn't even allow RTOR) to allow LTOR from 2-way to 1-way at a T-intersection.
https://www.google.com/maps/@40.6096868,-73.8190742,3a,75y,193.71h,88.53t/data=!3m6!1e1!3m4!1sKnloxMvHK6TsGqbAqOvusQ!2e0!7i16384!8i8192
It's also possible that those were formerly used as pedestrian signals before there were dedicated pedestrian signal heads installed there.
Edit to add: If you go back to the 2013 GSV imagery (https://www.google.com/maps/@40.6096222,-73.8189278,3a,75y,145.3h,84.77t/data=!3m6!1e1!3m4!1sIKLnXzv3NghKoWMQVByGGg!2e0!7i13312!8i6656), there isn't a stop line painted there. I think that might be a relatively recent addition, added in error.
Plausible explanation...until noticing that there are not vehicular signals facing the other direction on the crosswalk...
:confused:
Title: Re: Double left turns with permissive phasing
Post by: mrsman on September 15, 2019, 02:30:10 PM
Post by: mrsman on September 15, 2019, 02:30:10 PM
Quote from: roadfro on September 15, 2019, 02:18:17 PMQuote from: MNHighwayMan on September 15, 2019, 12:55:14 PMQuote from: roadfro on September 15, 2019, 12:13:20 PMQuote from: mrsman on September 15, 2019, 01:03:33 AMLooking around that intersection, I'm confused. I see the one way sign for the side street indicating it's one way away from this intersection. But why are there vehicular signals facing the side street and a stop bar on the side street? Was the side street formerly two way?
Here's an example from a relatively remote part of NYC (which generally doesn't even allow RTOR) to allow LTOR from 2-way to 1-way at a T-intersection.
https://www.google.com/maps/@40.6096868,-73.8190742,3a,75y,193.71h,88.53t/data=!3m6!1e1!3m4!1sKnloxMvHK6TsGqbAqOvusQ!2e0!7i16384!8i8192
It's also possible that those were formerly used as pedestrian signals before there were dedicated pedestrian signal heads installed there.
Edit to add: If you go back to the 2013 GSV imagery (https://www.google.com/maps/@40.6096222,-73.8189278,3a,75y,145.3h,84.77t/data=!3m6!1e1!3m4!1sIKLnXzv3NghKoWMQVByGGg!2e0!7i13312!8i6656), there isn't a stop line painted there. I think that might be a relatively recent addition, added in error.
Plausible explanation...until noticing that there are not vehicular signals facing the other direction on the crosswalk...
:confused:
I believe it was two-way at one point, even though it's very narrow. Making the street one-way allows for parking.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on September 15, 2019, 04:24:41 PM
Post by: jakeroot on September 15, 2019, 04:24:41 PM
Quote from: MNHighwayMan on September 13, 2019, 06:04:21 PMQuote from: mrsman on September 13, 2019, 05:18:48 PM
What really bothers me a lot about some of this is that the same signal means different things, based on the situation. It seems to ask the driver a lot to keep track of.
If I see a red left arrow crossing a two-way street, this is a protected only turn and I must wait for green arrow. This is of course the rule in the majority of other states in all circumstances.
These are two of the big reasons I don't like this Pacific Red Arrow law. (PRA for short, I'll call it from now on.) Consistency with traffic laws is key, and I'd call the PRA very inconsistent with both other states and with itself, for varying depending on the situation.
I would argue that the "PRA" is actually quite consistent, at least within the states that have it as law: you may turn on any red light, unless it's a left turn onto a two-way street. Any other unsafe turn can be marked with NTOR signs.
The law could be changed in states like ours to represent the FHWA preference, but that would end up banning many turns on red, thanks to WSDOT and ODOT's preference for using all-arrow signals over turn-only lanes, in lieu of lane-use signs.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on September 15, 2019, 06:15:05 PM
Post by: jakeroot on September 15, 2019, 06:15:05 PM
Quote from: US 89 on September 15, 2019, 05:58:37 PMQuote
These RTOR accidents constituted between 1% and 3% of all pedestrian or bicycle accidents in the studied locations.
It's a drop in the bucket. There are almost certainly better ways to reduce pedestrian/bicycle casualties that don't also involve unnecessary congestion.
I would agree. However, if you're in charge of the roads department in a city, and you're looking to work towards your Vision Zero goal, you'll take any improvement you can get, no matter how small. Washington DC and Seattle are two agencies that are quickly banning many turns on red. Problem is, they don't seem to recognize the ripple effects from banning these turns: intersection blocking, drivers continuing to turn even after the yellow light has disappeared, worsening traffic that results in increased driver impatience (and therefore increasingly stupid maneuvers on their part), etc. The study that I linked to above takes this into account: you could potentially improve safety for Users X with a turn-on-red ban, but there could be a likewise increase in collisions amongst Users Y, totally offsetting any improvements from the ban.
Title: Re: Double left turns with permissive phasing
Post by: Revive 755 on September 15, 2019, 10:19:49 PM
Post by: Revive 755 on September 15, 2019, 10:19:49 PM
Quote from: Duke87 on September 15, 2019, 09:05:31 PM
What is the argument against being able to legally turn right on red, say, here (https://www.google.com/maps/@38.9190066,-95.2611802,3a,89.4y,114.49h,83.02t/data=!3m6!1e1!3m4!1sUWFsYQFdWMknIEZF0iqytA!2e0!7i13312!8i6656)?
Even if there was a turn on red prohibition, there's no guarantee it will be well obeyed. I think Cook County, Illinois may be a good example of this, where a many unnecessary right on red prohibitions are degrading compliance with the more legitimate prohibitions.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on September 17, 2019, 03:27:21 AM
Post by: jakeroot on September 17, 2019, 03:27:21 AM
Found another of these (thanks to US 89 (OP here (https://www.aaroads.com/forum/index.php?topic=25653.msg2444043#msg2444043))).
The westbound-to-southbound double left turn from Isleta Blvd to...Isleta Blvd, in southwest Albuquerque, is a double permissive left, signalized with the relatively normal 5-section tower.
I understand there are others in Albuquerque, but I was not aware of any away from I-25.
Google Maps: https://goo.gl/maps/CNyuwfmRDaMmf1Yw9
(https://i.imgur.com/O9md13k.png)
The westbound-to-southbound double left turn from Isleta Blvd to...Isleta Blvd, in southwest Albuquerque, is a double permissive left, signalized with the relatively normal 5-section tower.
I understand there are others in Albuquerque, but I was not aware of any away from I-25.
Google Maps: https://goo.gl/maps/CNyuwfmRDaMmf1Yw9
(https://i.imgur.com/O9md13k.png)
Title: Re: Double left turns with permissive phasing
Post by: paulthemapguy on September 17, 2019, 06:17:36 PM
Post by: paulthemapguy on September 17, 2019, 06:17:36 PM
Found one of these for the first time last weekend, on the east side of Sioux Falls, along a section of SD-42 that was reconstructed last year. I'm guessing they're more commonly found in states with universally low traffic volumes.
(https://live.staticflickr.com/65535/48751134258_df577b7585_c.jpg) (https://flic.kr/p/2hgYiKy)
SD-YB1 (https://flic.kr/p/2hgYiKy) by Paul Drives (https://www.flickr.com/photos/138603251@N02/), on Flickr
Discussions are more enjoyable with photos :)
(https://live.staticflickr.com/65535/48751134258_df577b7585_c.jpg) (https://flic.kr/p/2hgYiKy)
SD-YB1 (https://flic.kr/p/2hgYiKy) by Paul Drives (https://www.flickr.com/photos/138603251@N02/), on Flickr
Discussions are more enjoyable with photos :)
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on September 18, 2019, 04:00:26 AM
Post by: jakeroot on September 18, 2019, 04:00:26 AM
Quote from: paulthemapguy on September 17, 2019, 06:17:36 PM
Found one of these for the first time last weekend, on the east side of Sioux Falls, along a section of SD-42 that was reconstructed last year. I'm guessing they're more commonly found in states with universally low traffic volumes.
https://live.staticflickr.com/65535/48751134258_df577b7585_c.jpg
Discussions are more enjoyable with photos :)
Nice! I would guess that the side-street in the photo with the dual-FYA setup (Highline Ave) is relatively quiet, which is actually a great reason to install this type of signal: they can allow side-street traffic to clear far quicker than with protected-only phasing, giving more green time to the primary artery (Arrowhead Parkway in this case).
I can't recall hearing of any others in South Dakota, so I'm guessing their state DOT must not have an objection to these types of installs. Especially as this is along a state route. Of course, this installation might have been installed/maintained by Sioux Falls directly, so that's not something I could be sure of.
Title: Re: Double left turns with permissive phasing
Post by: sprjus4 on September 19, 2019, 07:06:33 PM
Post by: sprjus4 on September 19, 2019, 07:06:33 PM
Don't know if this has been mentioned yet, but North Carolina has one at the I-87 / Wendell Falls Pkwy interchange outside of Raleigh
https://www.google.com/maps/@35.7833133,-78.4420373,3a,37.5y,301.81h,80.8t/data=!3m6!1e1!3m4!1sigXGx1Og4legzr1eTQ664Q!2e0!7i13312!8i6656
https://www.google.com/maps/@35.7833133,-78.4420373,3a,37.5y,301.81h,80.8t/data=!3m6!1e1!3m4!1sigXGx1Og4legzr1eTQ664Q!2e0!7i13312!8i6656
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on September 21, 2019, 02:33:10 PM
Post by: jakeroot on September 21, 2019, 02:33:10 PM
Quote from: sprjus4 on September 19, 2019, 07:06:33 PM
Don't know if this has been mentioned yet, but North Carolina has one at the I-87 / Wendell Falls Pkwy interchange outside of Raleigh
https://www.google.com/maps/@35.7833133,-78.4420373,3a,37.5y,301.81h,80.8t/data=!3m6!1e1!3m4!1sigXGx1Og4legzr1eTQ664Q!2e0!7i13312!8i6656
Had not been mentioned to my knowledge. Thanks for bringing it up. I know that NC uses this style of signal, but I hadn't seen one in a while. Not with a mast arm at least.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on September 21, 2019, 03:37:14 PM
Post by: jakeroot on September 21, 2019, 03:37:14 PM
Quote from: mrsman on September 19, 2019, 06:11:45 PM
No need for a battle. A uniform law of traffic safety should follow the majority practice. Look at this map showing the different left turn on red laws.
https://en.wikipedia.org/wiki/Turn_on_red#/media/File:Legality_of_left_turn_on_red_in_USA.svg
The vast majority of the states follow a consistent practice as shown in light blue. The dark blue states are more permissive (MI and the PNW). These can largely be rectified with a flashing red arrow, if warranted.
The red states are more restrictive and do not allow left on red from one-way to one-way. If they feel so strongly about it, they can put no turn on red signs at every relevant intersection.
IMO, NYC should be required to post their NTOR signs at every intersection where it applies, not just at the city limits. This would require the DOT to determine if the restriction is warranted, since signs cost money. NTOR is justified where there are a lot of pedestrian movements, but I can tell you that there are many intersections in the outer boroughs where RTOR is perfectly safe, even though currently illegal.
On top of all of this, we also have the question of right against a red right turn arrow. In a majority of states it is prohibited, and in some states it is no different than a red orb (and permissible after complete stop). Why should anyone have to research the state laws of 50 states just to drive in this country? If this were a uniform rule as well, the treatment would be easy. (IMO, this can be rectified with a flashing red arrow for states that currently permit turn against a red arrow.)
I've spent a huge amount of time thinking about this post. I was supposed to have been at the gym an hour ago, but here I am, still typing this post.
I am totally for FRA signals, but my primary worry continues to be that, in states like WA and OR, where protected left turns are remarkably common, many of the left turns onto one-way streets will not be swapped for FRA signals.
For example, both states disallow permissive left turns with more than one lane, but none of their double left turns onto on-ramps have NTOR signs that I've seen; basically, whether they realize it or not, they both have a ton of permissive left turns with two (or perhaps even three) lanes. Never mind the numerous left turns with only one lane that also allow turns on red, but again, would likely not be swapped for FRA signals.
I guess my only real course of action is to pursue a PE licence and take control of the signals myself!
Title: Re: Double left turns with permissive phasing
Post by: mrsman on September 27, 2019, 04:26:22 AM
Post by: mrsman on September 27, 2019, 04:26:22 AM
Quote from: jakeroot on September 21, 2019, 03:37:14 PMQuote from: mrsman on September 19, 2019, 06:11:45 PM
No need for a battle. A uniform law of traffic safety should follow the majority practice. Look at this map showing the different left turn on red laws.
https://en.wikipedia.org/wiki/Turn_on_red#/media/File:Legality_of_left_turn_on_red_in_USA.svg
The vast majority of the states follow a consistent practice as shown in light blue. The dark blue states are more permissive (MI and the PNW). These can largely be rectified with a flashing red arrow, if warranted.
The red states are more restrictive and do not allow left on red from one-way to one-way. If they feel so strongly about it, they can put no turn on red signs at every relevant intersection.
IMO, NYC should be required to post their NTOR signs at every intersection where it applies, not just at the city limits. This would require the DOT to determine if the restriction is warranted, since signs cost money. NTOR is justified where there are a lot of pedestrian movements, but I can tell you that there are many intersections in the outer boroughs where RTOR is perfectly safe, even though currently illegal.
On top of all of this, we also have the question of right against a red right turn arrow. In a majority of states it is prohibited, and in some states it is no different than a red orb (and permissible after complete stop). Why should anyone have to research the state laws of 50 states just to drive in this country? If this were a uniform rule as well, the treatment would be easy. (IMO, this can be rectified with a flashing red arrow for states that currently permit turn against a red arrow.)
I've spent a huge amount of time thinking about this post. I was supposed to have been at the gym an hour ago, but here I am, still typing this post.
I am totally for FRA signals, but my primary worry continues to be that, in states like WA and OR, where protected left turns are remarkably common, many of the left turns onto one-way streets will not be swapped for FRA signals.
For example, both states disallow permissive left turns with more than one lane, but none of their double left turns onto on-ramps have NTOR signs that I've seen; basically, whether they realize it or not, they both have a ton of permissive left turns with two (or perhaps even three) lanes. Never mind the numerous left turns with only one lane that also allow turns on red, but again, would likely not be swapped for FRA signals.
I guess my only real course of action is to pursue a PE licence and take control of the signals myself!
Thinking is good for you! :hmmm:
I think you've identified some key issues about implementing some of these suggestions I had made. I never suggested changing the effect of the laws onto the PNW (or onto the very restrictive northeastern states) would be easy or cheap, it's just that it is so important that the driving laws be made uniform, with exceptions signed on an intersection by intersection basis.
Of course, the best course of action would be replacement with the 4 aspect FYA signal - which generally seem to be capable of signalling for multiple scenarios.
Title: Re: Double left turns with permissive phasing
Post by: MASTERNC on September 30, 2019, 08:11:02 PM
Post by: MASTERNC on September 30, 2019, 08:11:02 PM
Found a double right turn FYA between Greensboro and High Point, NC on NC 68 at Penny Road. The red signals are balls instead of arrows, implying right on red is permitted.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on September 30, 2019, 11:04:16 PM
Post by: jakeroot on September 30, 2019, 11:04:16 PM
Quote from: MASTERNC on September 30, 2019, 08:11:02 PM
Found a double right turn FYA between Greensboro and High Point, NC on NC 68 at Penny Road. The red signals are balls instead of arrows, implying right on red is permitted.
Ah yes, found it here: https://goo.gl/maps/pQVs2jFKQmtbMpXD8
I don't see any pedestrian signal heads or crosswalks, however, so I'm not sure what purpose the dual FYA serves. Dual right turns with permissive phasing, requiring two lanes of traffic to yield to crossing pedestrians, doesn't appear to be as taboo as left turns (thanks to one less conflict), though they're fairly rare anyways, at least outside of downtown areas. A new one was just installed in my area last year, though it uses 5-section towers (https://goo.gl/maps/4uyVMdceEnAfEi126) (despite the city's recent attempts to use right-facing FYAs for pedestrian crossings (https://goo.gl/maps/Cs8QHQBgDC4JG6sb6) at T-intersections).
Quote from: mrsman on September 27, 2019, 04:26:22 AM
I think you've identified some key issues about implementing some of these suggestions I had made. I never suggested changing the effect of the laws onto the PNW (or onto the very restrictive northeastern states) would be easy or cheap, it's just that it is so important that the driving laws be made uniform, with exceptions signed on an intersection by intersection basis.
Of course, the best course of action would be replacement with the 4 aspect FYA signal - which generally seem to be capable of signalling for multiple scenarios.
What I haven't considered is the possibility of alerting local authorities to this law. I genuinely believe that engineers, locally, don't realize how liberal left turn laws actually are around here. Perhaps I could encourage WSDOT to study the possibility of using flashing red arrows at some on-ramps? Not sure how receptive they might be to that, but it beats the law changing without any modification to the traffic control infrastructure.
Title: Re: Double left turns with permissive phasing
Post by: MASTERNC on October 01, 2019, 06:57:39 PM
Post by: MASTERNC on October 01, 2019, 06:57:39 PM
Quote from: jakeroot on September 30, 2019, 11:04:16 PMQuote from: MASTERNC on September 30, 2019, 08:11:02 PM
Found a double right turn FYA between Greensboro and High Point, NC on NC 68 at Penny Road. The red signals are balls instead of arrows, implying right on red is permitted.
Ah yes, found it here: https://goo.gl/maps/pQVs2jFKQmtbMpXD8
I don't see any pedestrian signal heads or crosswalks, however, so I'm not sure what purpose the dual FYA serves. Dual right turns with permissive phasing, requiring two lanes of traffic to yield to crossing pedestrians, doesn't appear to be as taboo as left turns (thanks to one less conflict), though they're fairly rare anyways, at least outside of downtown areas. A new one was just installed in my area last year, though it uses 5-section towers (https://goo.gl/maps/4uyVMdceEnAfEi126) (despite the city's recent attempts to use right-facing FYAs for pedestrian crossings (https://goo.gl/maps/Cs8QHQBgDC4JG6sb6) at T-intersections).
Found another one around Biltmore Village outside Asheville that does appear to have a pedestrian crossing. Thru signal is green when the right turns have the FYA and the pedestrian signal is active.
Title: Re: Double left turns with permissive phasing
Post by: motorola870 on October 01, 2019, 07:53:55 PM
Post by: motorola870 on October 01, 2019, 07:53:55 PM
Quote from: MASTERNC on October 01, 2019, 06:57:39 PMWe have double left FYAs now in Arlington Texas at a few of intersections one I think should not qualify as it is in a busy shopping area and it is in front of a chick fil a that is consistently packed and drive thru is usually bumper to bumper. We used to have a couple of solid green permissive 5 segment left on yield lights back in the 1990s on interstate 20 when they first opened a reconstructed bridge that went from 3 lanes to 8 lanes wide over time it was phased to two protected left turn lanes on each side of the bridge.Quote from: jakeroot on September 30, 2019, 11:04:16 PMQuote from: MASTERNC on September 30, 2019, 08:11:02 PM
Found a double right turn FYA between Greensboro and High Point, NC on NC 68 at Penny Road. The red signals are balls instead of arrows, implying right on red is permitted.
Ah yes, found it here: https://goo.gl/maps/pQVs2jFKQmtbMpXD8
I don't see any pedestrian signal heads or crosswalks, however, so I'm not sure what purpose the dual FYA serves. Dual right turns with permissive phasing, requiring two lanes of traffic to yield to crossing pedestrians, doesn't appear to be as taboo as left turns (thanks to one less conflict), though they're fairly rare anyways, at least outside of downtown areas. A new one was just installed in my area last year, though it uses 5-section towers (https://goo.gl/maps/4uyVMdceEnAfEi126) (despite the city's recent attempts to use right-facing FYAs for pedestrian crossings (https://goo.gl/maps/Cs8QHQBgDC4JG6sb6) at T-intersections).
Found another one around Biltmore Village outside Asheville that does appear to have a pedestrian crossing. Thru signal is green when the right turns have the FYA and the pedestrian signal is active.
Title: Re: Double left turns with permissive phasing
Post by: MNHighwayMan on October 02, 2019, 10:11:18 AM
Post by: MNHighwayMan on October 02, 2019, 10:11:18 AM
Quote from: motorola870 on October 01, 2019, 07:53:55 PM
[hard to read post]
Punctuation and complete sentences are your friends.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on October 02, 2019, 01:09:15 PM
Post by: jakeroot on October 02, 2019, 01:09:15 PM
Quote from: MASTERNC on October 01, 2019, 06:57:39 PM
Found another one around Biltmore Village outside Asheville that does appear to have a pedestrian crossing. Thru signal is green when the right turns have the FYA and the pedestrian signal is active.
Any Google Maps link?
Title: Re: Double left turns with permissive phasing
Post by: MASTERNC on October 06, 2019, 06:15:48 PM
Post by: MASTERNC on October 06, 2019, 06:15:48 PM
Quote from: jakeroot on October 02, 2019, 01:09:15 PMQuote from: MASTERNC on October 01, 2019, 06:57:39 PM
Found another one around Biltmore Village outside Asheville that does appear to have a pedestrian crossing. Thru signal is green when the right turns have the FYA and the pedestrian signal is active.
Any Google Maps link?
https://goo.gl/maps/cLpjzYnQmNQUNup8A
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on October 06, 2019, 11:46:53 PM
Post by: jakeroot on October 06, 2019, 11:46:53 PM
Quote from: MASTERNC on October 06, 2019, 06:15:48 PMQuote from: jakeroot on October 02, 2019, 01:09:15 PMQuote from: MASTERNC on October 01, 2019, 06:57:39 PM
Found another one around Biltmore Village outside Asheville that does appear to have a pedestrian crossing. Thru signal is green when the right turns have the FYA and the pedestrian signal is active.
Any Google Maps link?
https://goo.gl/maps/cLpjzYnQmNQUNup8A
Cheers. This one definitely has a crosswalk!
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on October 06, 2019, 11:58:00 PM
Post by: jakeroot on October 06, 2019, 11:58:00 PM
Found three new ones in Port Angeles, WA this afternoon. All are fully permissive, and are double left turns onto a one-way street from a two-way street with option lanes.
Historic imagery suggests that these have been in place since at least the turn of the century.
N Oak St @ W 1 St (https://goo.gl/maps/JUZ6pH7vqAcchuZr7)
N Race St @ E Front St (US-101) (https://goo.gl/maps/sbizA41gpCu3iSFcA)
N Lincoln St @ E Front St (https://goo.gl/maps/yhpuXh2zLN7BPSoc8)
(image below of the first link above)
(https://i.imgur.com/EWQJO5f.jpg)
Historic imagery suggests that these have been in place since at least the turn of the century.
N Oak St @ W 1 St (https://goo.gl/maps/JUZ6pH7vqAcchuZr7)
N Race St @ E Front St (US-101) (https://goo.gl/maps/sbizA41gpCu3iSFcA)
N Lincoln St @ E Front St (https://goo.gl/maps/yhpuXh2zLN7BPSoc8)
(image below of the first link above)
(https://i.imgur.com/EWQJO5f.jpg)
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on October 20, 2019, 11:34:42 AM
Post by: fwydriver405 on October 20, 2019, 11:34:42 AM
Quote from: jakeroot on September 11, 2019, 11:06:02 PMQuote from: mrsman on September 11, 2019, 08:15:47 PM
So you say that's one way of keeping track of when doing you left turn from a two way to a one way is by glancing at the through signal and letting that determine how you approached the intersection. In my mind that is very counterintuitive. Especially in the era of the fya, especially when they are used to prevent a yellow trap, we are taught that when making a left turn you need to focus solely on the left turn signal and ignore what the thru signal is doing. To the extent that this is not being done, we have already discussed in the perceived yellow track threads.
It's acceptable to rely on the parallel through traffic in this instance, because there is no oncoming left turn that may preemptively end the parallel through phase. The next time they get a red, would be the next time that I also would need to finish my turn.
If you look at the video I made about this maneuver, you can see (at 0:46 when I first arrive at the left turn) that the parallel traffic has a red light. Because the cross-traffic is one-way, I know that it can't be red because of an oncoming left turn. I can also see traffic coming off the freeway from my right. Turning through a gap here might be unwise, so I wait for them to receive a red light. Because the double left here is lagging, the through traffic gets to go next, while the left turn onto the freeway must wait. Again, because there is no oncoming left turn, I need not be worried about the parallel through traffic receiving a red light while I'm waiting. Though to the point that it matters, I'm still legally allowed to turn on red, even if they somehow ended up with a red light. Not that that would make much sense.
In this video, however, I do make a left turn on red while the parallel traffic also has a red light. This situation is relatively uncommon, and I find it more acceptable when traffic is quiet. Skip to 0:27:
https://youtu.be/2Qa7vD0_TkY?t=46
Not sure if this counts, but I may have found an unusual case in Boston of a similar case where left on red arrow is permitted with "permissive phasing":
Atlantic and Congress St (https://www.google.com/maps/@42.3537714,-71.0537625,3a,90y,133.06h,85.91t/data=!3m7!1e1!3m5!1s6lWHpxqbCkyRXLPBdjI58A!2e0!6s%2F%2Fgeo1.ggpht.com%2Fcbk%3Fpanoid%3D6lWHpxqbCkyRXLPBdjI58A%26output%3Dthumbnail%26cb_client%3Dsearch.revgeo_and_fetch.gps%26thumb%3D2%26w%3D96%26h%3D64%26yaw%3D328.80402%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192)
In this case, Atlantic is one way, the Congress approach coming from Post Office Sq is one way and the Congress approach coming from S. Boston is two way. On Congress, when the Post Office Sq thru approach is green, and the S. Boston approach has green right arrows, the left-turning traffic from Congress to Atlantic gets a red-left arrow. Because no sign is posted saying NO TURN ON RED on the Post Office approach, MA law doesn't distinguish between red arrows and balls, and also allows left turns on red from a one way to a one way, could this technically be a double permissive left? The left turn here is lagging left by the way.
BTW (edited 2021-11-01, incorrect phasing initially posted, corrected): There is a ped phase after the right turning traffic phase ends. So in hindsight, the phasing goes: right turning traffic to Atlantic, pedestrian phase crossing Atlantic, then the left turns onto Atlantic proceed before Atlantic Ave traffic is served.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on October 20, 2019, 02:19:54 PM
Post by: jakeroot on October 20, 2019, 02:19:54 PM
^^^^^^^^^^
Yeah, I think that would count! Given Mass law, although it may not be a truly "permissive" turn (where no stop would be required), it operates exactly like one, and it's not any different than my WA video you quoted. So I'm counting it! These are almost like half examples, if you may.
For that intersection you posted, the oncoming right turn could operate with green arrows, but I think it might be better to operate with flashing yellow arrows during the the WALK phase, with the double left operating with its own exclusive phase after that. Right now it seems to be a three-phase intersection.
I'm actually a bit surprised that there's an NTOR sign for that double right, but not the double left. I get the feeling that the city of Boston may have forgotten about the law.
Yeah, I think that would count! Given Mass law, although it may not be a truly "permissive" turn (where no stop would be required), it operates exactly like one, and it's not any different than my WA video you quoted. So I'm counting it! These are almost like half examples, if you may.
For that intersection you posted, the oncoming right turn could operate with green arrows, but I think it might be better to operate with flashing yellow arrows during the the WALK phase, with the double left operating with its own exclusive phase after that. Right now it seems to be a three-phase intersection.
I'm actually a bit surprised that there's an NTOR sign for that double right, but not the double left. I get the feeling that the city of Boston may have forgotten about the law.
Title: Re: Double left turns with permissive phasing
Post by: deathtopumpkins on October 21, 2019, 04:30:32 PM
Post by: deathtopumpkins on October 21, 2019, 04:30:32 PM
If we're counting LTOR between one-ways as "permissive" (which it isn't), then there are more examples all along the Greenway in Boston.
Sudbury St @ Cross St: https://goo.gl/maps/sArJSpC1nUEs2Zs37
Milk St @ Atlantic Ave: https://goo.gl/maps/sArJSpC1nUEs2Zs37
India St @ Surface Rd: https://goo.gl/maps/2vLLz357WL8SRXEx5
High St @ Atlantic Ave: https://goo.gl/maps/HDR84m6ynSXYDAM5A
Pearl St @ Purchase St: https://goo.gl/maps/ZV1NYtBFa1qHm597A
And elsewhere in the city:
Albany St @ Traveler St: https://goo.gl/maps/djqoMivVe89FKoWm8
Dartmouth St @ Huntington Ave: https://goo.gl/maps/enTmFGUsrog2E7KH9
Arlington St @ Boylston St: https://goo.gl/maps/ug4gTjVZLEPcz4GE8
The odds of anyone actually turning left on red at any of these is slim to none though, as no one around here seems to actually know it's legal (a coworker of mine even got pulled over for it once).
Sudbury St @ Cross St: https://goo.gl/maps/sArJSpC1nUEs2Zs37
Milk St @ Atlantic Ave: https://goo.gl/maps/sArJSpC1nUEs2Zs37
India St @ Surface Rd: https://goo.gl/maps/2vLLz357WL8SRXEx5
High St @ Atlantic Ave: https://goo.gl/maps/HDR84m6ynSXYDAM5A
Pearl St @ Purchase St: https://goo.gl/maps/ZV1NYtBFa1qHm597A
And elsewhere in the city:
Albany St @ Traveler St: https://goo.gl/maps/djqoMivVe89FKoWm8
Dartmouth St @ Huntington Ave: https://goo.gl/maps/enTmFGUsrog2E7KH9
Arlington St @ Boylston St: https://goo.gl/maps/ug4gTjVZLEPcz4GE8
The odds of anyone actually turning left on red at any of these is slim to none though, as no one around here seems to actually know it's legal (a coworker of mine even got pulled over for it once).
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on October 21, 2019, 05:02:06 PM
Post by: jakeroot on October 21, 2019, 05:02:06 PM
Quote from: deathtopumpkins on October 21, 2019, 04:30:32 PM
If we're counting LTOR between one-ways as "permissive" (which it isn't), then there are more examples all along the Greenway in Boston.
I don't think a turn counts as fully protected, unless you have to wait for a green arrow. If these double left turns in Boston do not require you to wait for a green arrow, then I don't see why they wouldn't count as a double permissive left turn. Besides that, it's my thread, and I make the rules. So there.
Title: Re: Double left turns with permissive phasing
Post by: roadfro on October 22, 2019, 11:14:29 AM
Post by: roadfro on October 22, 2019, 11:14:29 AM
Quote from: jakeroot on October 21, 2019, 05:02:06 PMQuote from: deathtopumpkins on October 21, 2019, 04:30:32 PM
If we're counting LTOR between one-ways as "permissive" (which it isn't), then there are more examples all along the Greenway in Boston.
I don't think a turn counts as fully protected, unless you have to wait for a green arrow. If these double left turns in Boston do not require you to wait for a green arrow, then I don't see why they wouldn't count as a double permissive left turn. Besides that, it's my thread, and I make the rules. So there.
In practice, protected and permitted turning modes are referring to the phase of the traffic signal in which vehicles can make a left turn, and how that phase interact with other active phases. It's really only describing the operation of the green or flashing yellow/red intervals that allow the turn manuever–legal turns made during the red interval after a stop doesn't make a particular turning movement permitted.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on October 22, 2019, 09:53:56 PM
Post by: jakeroot on October 22, 2019, 09:53:56 PM
Quote from: roadfro on October 22, 2019, 11:14:29 AMQuote from: jakeroot on October 21, 2019, 05:02:06 PMQuote from: deathtopumpkins on October 21, 2019, 04:30:32 PM
If we're counting LTOR between one-ways as "permissive" (which it isn't), then there are more examples all along the Greenway in Boston.
I don't think a turn counts as fully protected, unless you have to wait for a green arrow. If these double left turns in Boston do not require you to wait for a green arrow, then I don't see why they wouldn't count as a double permissive left turn. Besides that, it's my thread, and I make the rules. So there.
In practice, protected and permitted turning modes are referring to the phase of the traffic signal in which vehicles can make a left turn, and how that phase interact with other active phases. It's really only describing the operation of the green or flashing yellow/red intervals that allow the turn manuever–legal turns made during the red interval after a stop doesn't make a particular turning movement permitted.
I'm not sure I would agree with that. If you are legally permitted to turn against a red signal, I don't see how that turn could be considered "protected". In the traditional sense, yes, red arrow/green arrow = protected only, and green ball/FYA = permitted turn, but a red light that permits turns on red is not only "permissive", it's more permissive than traditional left turns, because turns can be made no matter what the display is.
For example, this left turn (https://goo.gl/maps/DUcu4RGP4WYmF1XBA) can be made during the "yield on green" phase, the green left arrow phase, and the red orb phase. Obviously permissive. But what about with dedicated signals w/o a "permissive" (read: green orb/FYA) phase? At these types of intersections (https://goo.gl/maps/mdR6pmr6PUJyC9jS9), you can still turn during the red phase, as it's onto a one-way street. And, of course, you also turn during the green arrow phase. Because left turns can still be made at a driver's discretion, in a sense, it's still a permissive turn.
Pretty much every right turn is a permissive turn, as you don't need to wait for a green light. I think you would agree that a fully-protected right turn would be one where you must wait for a green arrow. I don't see how that's any different than left turns that can be made on red: in neither case must a driver wait for a green light.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on October 22, 2019, 11:56:08 PM
Post by: fwydriver405 on October 22, 2019, 11:56:08 PM
Quote from: deathtopumpkins on October 21, 2019, 04:30:32 PM
If we're counting LTOR between one-ways as "permissive" (which it isn't), then there are more examples all along the Greenway in Boston.
Sudbury St @ Cross St: https://goo.gl/maps/sArJSpC1nUEs2Zs37
Milk St @ Atlantic Ave: https://goo.gl/maps/sArJSpC1nUEs2Zs37
India St @ Surface Rd: https://goo.gl/maps/2vLLz357WL8SRXEx5
High St @ Atlantic Ave: https://goo.gl/maps/HDR84m6ynSXYDAM5A
Pearl St @ Purchase St: https://goo.gl/maps/ZV1NYtBFa1qHm597A
And elsewhere in the city:
Albany St @ Traveler St: https://goo.gl/maps/djqoMivVe89FKoWm8
Dartmouth St @ Huntington Ave: https://goo.gl/maps/enTmFGUsrog2E7KH9
Arlington St @ Boylston St: https://goo.gl/maps/ug4gTjVZLEPcz4GE8
The odds of anyone actually turning left on red at any of these is slim to none though, as no one around here seems to actually know it's legal (a coworker of mine even got pulled over for it once).
And two more in Somerville as well:
Main and Beacham Street (new installation): Streetview (https://www.google.com/maps/@42.3850559,-71.0749895,3a,86.3y,15.1h,93.15t/data=!3m6!1e1!3m4!1s5DFPhnlpXHmDzrW3ws8-1Q!2e0!7i16384!8i8192)
(https://i.ibb.co/RC2HsT5/IMG-5763.png) (https://ibb.co/9qnY1HM)
Medford St and MA 28: Streetview (https://www.google.com/maps/@42.377114,-71.0889362,3a,40.4y,54.69h,89.42t/data=!3m6!1e1!3m4!1sDjBaw1a6i2hZIvSlsXnNJw!2e0!7i16384!8i8192)
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on October 22, 2019, 11:59:41 PM
Post by: jakeroot on October 22, 2019, 11:59:41 PM
Actually, I think I may need back up a bit. Ideally, these double left turns would need to have either something in front of them to yield to, or something to the left. If it's just "pull up, look right, and go", maybe it's permissive in my book, but it doesn't really fit the idea of this thread. Which was more to highlight double left turns that have to yield to something coming towards them, not necessarily something coming from the right.
Sorry for the late clarification.
Sorry for the late clarification.
Title: Re: Double left turns with permissive phasing
Post by: roadfro on October 23, 2019, 10:15:45 AM
Post by: roadfro on October 23, 2019, 10:15:45 AM
Quote from: jakeroot on October 22, 2019, 09:53:56 PMQuote from: roadfro on October 22, 2019, 11:14:29 AMQuote from: jakeroot on October 21, 2019, 05:02:06 PM
I don't think a turn counts as fully protected, unless you have to wait for a green arrow. If these double left turns in Boston do not require you to wait for a green arrow, then I don't see why they wouldn't count as a double permissive left turn. Besides that, it's my thread, and I make the rules. So there.
In practice, protected and permitted turning modes are referring to the phase of the traffic signal in which vehicles can make a left turn, and how that phase interact with other active phases. It's really only describing the operation of the green or flashing yellow/red intervals that allow the turn manuever–legal turns made during the red interval after a stop doesn't make a particular turning movement permitted.
I'm not sure I would agree with that. If you are legally permitted to turn against a red signal, I don't see how that turn could be considered "protected". In the traditional sense, yes, red arrow/green arrow = protected only, and green ball/FYA = permitted turn, but a red light that permits turns on red is not only "permissive", it's more permissive than traditional left turns, because turns can be made no matter what the display is.
For example, this left turn (https://goo.gl/maps/DUcu4RGP4WYmF1XBA) can be made during the "yield on green" phase, the green left arrow phase, and the red orb phase. Obviously permissive. But what about with dedicated signals w/o a "permissive" (read: green orb/FYA) phase? At these types of intersections (https://goo.gl/maps/mdR6pmr6PUJyC9jS9), you can still turn during the red phase, as it's onto a one-way street. And, of course, you also turn during the green arrow phase. Because left turns can still be made at a driver's discretion, in a sense, it's still a permissive turn.
Pretty much every right turn is a permissive turn, as you don't need to wait for a green light. I think you would agree that a fully-protected right turn would be one where you must wait for a green arrow. I don't see how that's any different than left turns that can be made on red: in neither case must a driver wait for a green light.
Jake, you're mixing terms of traffic signal control with what the law allows drivers to do on certain indications.
For reference, here's MUTCD definitions from section 1A.13 (https://mutcd.fhwa.dot.gov/htm/2009r1r2/part1/part1a.htm):
QuoteAnother reference, the first version of the Traffic Signal Timing Manual on FHWA's website. Chapter 4.3 (https://ops.fhwa.dot.gov/publications/fhwahop08024/chapter4.htm#4.3) discusses left turn operation:
144. Permissive Mode–a mode of traffic control signal operation in which left or right turns are permitted to be made after yielding to pedestrians, if any, and/or opposing traffic, if any. When a CIRCULAR GREEN signal indication is displayed, both left and right turns are permitted unless otherwise prohibited by another traffic control device. When a flashing YELLOW ARROW or flashing RED ARROW signal indication is displayed, the turn indicated by the arrow is permitted.
160. Protected Mode–a mode of traffic control signal operation in which left or right turns are permitted to be made when a left or right GREEN ARROW signal indication is displayed.
Quote
4.3.1 Permissive Only Left-Turn Phasing
Permissive only operation requires left-turning drivers to yield to the conflicting vehicle and pedestrian traffic streams before completing the turn. In the permissive mode, the left-turn movement is served concurrently with the adjacent through movement. Both the left turn and the opposing through movements are presented with a circular green indication. Thus, in this left turn display option, a green arrow is never provided. ...
4.3.2 Protected Only Left-Turn Phasing
Protected only operation assigns the right-of-way to drivers turning left at the intersection and allows turns to be made only on a green arrow display. This operation provides for efficient left-turn movement service; however, the added left-turn phase increases the lost time within the cycle length and may increase delay to the other movements. An exclusive left-turn lane is typically provided with this phasing as shown in Figure 4-7. The left-turn phase is indicated by a green arrow signal indication. This type operation is recognized to provide the safest left-turn operation. ...
A protected movement is one where the signal has assigned right of way to that movement, "protecting" it (in a sense) from conflicts with other movements in the intersection. Permitted turns are made during an adjacent circular green phase that has right of way, after yielding to other traffic/pedestrians that also have right of way. So a NB protected left turn is assigned the right of way during its signal phase, protecting it from conflicting oncoming and cross traffic (as well as conflicting pedestrian crossings)–but a SB right turn on red at the same time is not considered a permitted movement (even though it may be legal to do so) because SB traffic does not have right of way during that phase.
Title: Re: Double left turns with permissive phasing
Post by: stevashe on October 24, 2019, 01:02:33 AM
Post by: stevashe on October 24, 2019, 01:02:33 AM
Quote from: jakeroot on September 30, 2019, 11:04:16 PMQuote from: mrsman on September 27, 2019, 04:26:22 AM
I think you've identified some key issues about implementing some of these suggestions I had made. I never suggested changing the effect of the laws onto the PNW (or onto the very restrictive northeastern states) would be easy or cheap, it's just that it is so important that the driving laws be made uniform, with exceptions signed on an intersection by intersection basis.
Of course, the best course of action would be replacement with the 4 aspect FYA signal - which generally seem to be capable of signalling for multiple scenarios.
What I haven't considered is the possibility of alerting local authorities to this law. I genuinely believe that engineers, locally, don't realize how liberal left turn laws actually are around here. Perhaps I could encourage WSDOT to study the possibility of using flashing red arrows at some on-ramps? Not sure how receptive they might be to that, but it beats the law changing without any modification to the traffic control infrastructure.
So I was aware that left turns on red were allowed from two-way streets in Washington and a few other states before finding this forum, but I hadn't considered the possibility that freeway ramps could count as a "one-way street". When I saw people discussing such a possibility on the forum, I remained a bit dubious since that seemed equivalent to arguing that turning left on red to a divided highway (with a large median) would be allowed if you were waiting at a light in the median, which I'm fairly sure would not count. I also had never seen anyone perform this movement, which made me question the idea further.
However, after paying specific attention at on-ramps, I did manage to see someone do it at the exit nearest my house, so I decided to see if I could research a definitive answer to this. I came up with this article (https://www.kitsapsun.com/story/news/2019/07/26/road-warrior-no-free-left-onto-ramp/1833502001/), where the answer to the reporter's inquiry to the Washington State Patrol was that left turns onto freeway on-ramps are not allowed. So regardless of what the intent of the law is, WSP's interpretation seems to be that such movements are not allowed.
Although, the quote in the article also states "freeway on-ramps are not considered one-way streets unless marked as such" which just makes me then wonder what such a marking would be? If it's only one-way signs, then many ramps would still qualify as lots of ramps do have them.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on October 25, 2019, 01:36:45 AM
Post by: jakeroot on October 25, 2019, 01:36:45 AM
Quote from: stevashe on October 24, 2019, 01:02:33 AMQuote from: jakeroot on September 30, 2019, 11:04:16 PMQuote from: mrsman on September 27, 2019, 04:26:22 AM
I think you've identified some key issues about implementing some of these suggestions I had made. I never suggested changing the effect of the laws onto the PNW (or onto the very restrictive northeastern states) would be easy or cheap, it's just that it is so important that the driving laws be made uniform, with exceptions signed on an intersection by intersection basis.
Of course, the best course of action would be replacement with the 4 aspect FYA signal - which generally seem to be capable of signalling for multiple scenarios.
What I haven't considered is the possibility of alerting local authorities to this law. I genuinely believe that engineers, locally, don't realize how liberal left turn laws actually are around here. Perhaps I could encourage WSDOT to study the possibility of using flashing red arrows at some on-ramps? Not sure how receptive they might be to that, but it beats the law changing without any modification to the traffic control infrastructure.
So I was aware that left turns on red were allowed from two-way streets in Washington and a few other states before finding this forum, but I hadn't considered the possibility that freeway ramps could count as a "one-way street". When I saw people discussing such a possibility on the forum, I remained a bit dubious since that seemed equivalent to arguing that turning left on red to a divided highway (with a large median) would be allowed if you were waiting at a light in the median, which I'm fairly sure would not count. I also had never seen anyone perform this movement, which made me question the idea further.
However, after paying specific attention at on-ramps, I did manage to see someone do it at the exit nearest my house, so I decided to see if I could research a definitive answer to this. I came up with this article (https://www.kitsapsun.com/story/news/2019/07/26/road-warrior-no-free-left-onto-ramp/1833502001/), where the answer to the reporter's inquiry to the Washington State Patrol was that left turns onto freeway on-ramps are not allowed. So regardless of what the intent of the law is, WSP's interpretation seems to be that such movements are not allowed.
Although, the quote in the article also states "freeway on-ramps are not considered one-way streets unless marked as such" which just makes me then wonder what such a marking would be? If it's only one-way signs, then many ramps would still qualify as lots of ramps do have them.
As the article states, that is simply one of several interpretations that I've seen over the years. For every article that comes out against the maneuver, there's another that comes out in favor.
My instinct is that the law does not reasonably differ between "streets" and other types of roadways for any ticket to stick. For the record, I have performed the maneuver around police, mostly to test my interpretation, and have not been pulled over. RCW 47.04.010 provides the definition of "highways": "Every way, lane, road, street, boulevard, and every way or place in the state of Washington open as a matter of right to public vehicular travel both inside and outside the limits of incorporated cities and towns". Because those smaller, individual terms are not defined elsewhere in the RCW, any reference to those rights-of-way should be considered "highways" (so streets = highways, boulevards = highways, etc).
According to that article, "An on-ramp is considered a designated part of the freeway". But what part of the RCW supports that assertion? I see no indication in the law that would prohibit the movement onto any one-way roads just because they're part of a "highway" or "freeway". Plus there is no reference to the term "freeway" except as defined for use on signage (WAC 468-70-020). She says that "on-ramps do not fit under the RCW 46.61.055 (section 3-c) that allows drivers to take a left after stopping at a light onto a one-way street". Yet, there is no indication in that RCW that there would be any situations where it would not apply, except when "a sign posted by competent authority prohibits such movement". I don't even see the term "on ramp" in the RCW, so how would drivers be able to assume that any one-way stretch of pavement is anything but a "one way street"?
Yeah, I'm going to keep doing it. RCW 46.61.135, which defines one-way streets, indicates that it must be marked by "official traffic control device", which include "all signs, signals, markings and devices" (RCW 46.04.611). If the markings make it clear that it's a one-way street, I don't need a sign to make it legal.
Title: Re: Double left turns with permissive phasing
Post by: jeffandnicole on October 25, 2019, 06:20:52 AM
Post by: jeffandnicole on October 25, 2019, 06:20:52 AM
Quote from: stevashe on October 24, 2019, 01:02:33 AMQuote from: jakeroot on September 30, 2019, 11:04:16 PMQuote from: mrsman on September 27, 2019, 04:26:22 AM
I think you've identified some key issues about implementing some of these suggestions I had made. I never suggested changing the effect of the laws onto the PNW (or onto the very restrictive northeastern states) would be easy or cheap, it's just that it is so important that the driving laws be made uniform, with exceptions signed on an intersection by intersection basis.
Of course, the best course of action would be replacement with the 4 aspect FYA signal - which generally seem to be capable of signalling for multiple scenarios.
What I haven't considered is the possibility of alerting local authorities to this law. I genuinely believe that engineers, locally, don't realize how liberal left turn laws actually are around here. Perhaps I could encourage WSDOT to study the possibility of using flashing red arrows at some on-ramps? Not sure how receptive they might be to that, but it beats the law changing without any modification to the traffic control infrastructure.
So I was aware that left turns on red were allowed from two-way streets in Washington and a few other states before finding this forum, but I hadn't considered the possibility that freeway ramps could count as a "one-way street". When I saw people discussing such a possibility on the forum, I remained a bit dubious since that seemed equivalent to arguing that turning left on red to a divided highway (with a large median) would be allowed if you were waiting at a light in the median, which I'm fairly sure would not count. I also had never seen anyone perform this movement, which made me question the idea further.
However, after paying specific attention at on-ramps, I did manage to see someone do it at the exit nearest my house, so I decided to see if I could research a definitive answer to this. I came up with this article (https://www.kitsapsun.com/story/news/2019/07/26/road-warrior-no-free-left-onto-ramp/1833502001/), where the answer to the reporter's inquiry to the Washington State Patrol was that left turns onto freeway on-ramps are not allowed. So regardless of what the intent of the law is, WSP's interpretation seems to be that such movements are not allowed.
Although, the quote in the article also states "freeway on-ramps are not considered one-way streets unless marked as such" which just makes me then wonder what such a marking would be? If it's only one-way signs, then many ramps would still qualify as lots of ramps do have them.
Never take an article written by some journalist who barely rolls out of bed to write their stories as fact (no, seriously - they will sit at home and write up their story on their iPhone while making a few phone calls. That's being a journalist today).
Check out this line within the article: "They said they would pull a drive over if they saw this," . How does someone pull over a drive? This hack of a reporter is what you're basing your opinion on?
The only real source of the law, believe it or not, isn't the State Police. It's the judges who make the decisions, and the lawmakers who wrote the law. This newspaper didn't even use the State Police. They used a communications CONSULTANT to the state police. Basically, they talked to someone who works with numerous different companies on any given day, and probably had very little knowledge of police policies and the intent of the law. Or, very likely, they talked to a high school friend that had some sort of job that sounded like it was important and knowledgeable.
Heck, even the journalist said that he read another source that contradicted his own source, but overruled it himself based on that there was no source listed. Couldn't even be bothered to contact his media friends to locate the source.
I would ignore this communications consultant's theory on what is a one way street. Later today, she'll probably be a communications consultant on which Halloween candy to buy that has fewer calories.
Title: Re: Double left turns with permissive phasing
Post by: stevashe on October 26, 2019, 03:48:12 AM
Post by: stevashe on October 26, 2019, 03:48:12 AM
Quote from: jeffandnicole on October 25, 2019, 06:20:52 AM
Never take an article written by some journalist who barely rolls out of bed to write their stories as fact (no, seriously - they will sit at home and write up their story on their iPhone while making a few phone calls. That's being a journalist today).
You Clearly haven't done a very close reading of the article from what you've said here.
Quote
Check out this line within the article: "They said they would pull a drive over if they saw this," . How does someone pull over a drive? This hack of a reporter is what you're basing your opinion on?
It's a one letter typo, come on. And it's quote from a reader question, so it probably wasn't even written by the reporter. Sure the reporter could have fixed the reader's typo I guess but I still don't think that says anything about the reporter's skills!
Quote
The only real source of the law, believe it or not, isn't the State Police. It's the judges who make the decisions, and the lawmakers who wrote the law. This newspaper didn't even use the State Police. They used a communications CONSULTANT to the state police. Basically, they talked to someone who works with numerous different companies on any given day, and probably had very little knowledge of police policies and the intent of the law. Or, very likely, they talked to a high school friend that had some sort of job that sounded like it was important and knowledgeable.
Again you seem not to have read the article very closely. The reporter reached out to a contact at WSP, and they got back to him through a communications consultant. If you're upset about such a consultant being used, you should be mad at WSP, not the reporter.
And you are correct that the judge would be the ultimate authority to interpret the law, but it is the police who actually enforce it, my main point is that you should expect to potentially be pulled over.
Quote
Heck, even the journalist said that he read another source that contradicted his own source, but overruled it himself based on that there was no source listed. Couldn't even be bothered to contact his media friends to locate the source.
Again you've missed something. He actually contacted his source again because of the contradiction, and that source "kicked it up to headquarters", who then got back to him through the communications consultant.
Also Jake, I'd advise against bringing this up to WSDOT. From my limited interactions with them I'd expect them to sooner put up "No Turn on Red" signs at every on-ramp in the state than put in any red flashing arrows. They made a big fuss over us putting in a curb on the centerline of Lake City Way (we were working for SDOT) which technically reduced the lane width 6 inches below their standard (even though it takes up the exact same space as the double yellow line already there, and it's not like that's typically driven on). They just wouldn't let it go and got almost hysterical at any rational arguments for it, it was a bit strange.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on October 27, 2019, 04:10:04 AM
Post by: jakeroot on October 27, 2019, 04:10:04 AM
Alright, here's further evidence that the story needs to be ignored:
1) The RCW on "Traffic control signal legends" (46.61.055) uses the term "street" in all references to left and right turns on red. So is it also not legal to turn right on red, onto any sort of highway infrastructure, because they're not "streets"?? fuck off...
If LTOR isn't legal onto an on-ramp, then, by the book, neither are right turns.
2) This left turn in Vancouver, onto an on-ramp, is marked with "no turn on red" signs, implying that the maneuver would be legal without the signs. Why would WSDOT install this sign, if the turn is illegal anyways?
Based on my above image, I think WSDOT may be well-aware of the law. They just keep quiet about it.
1) The RCW on "Traffic control signal legends" (46.61.055) uses the term "street" in all references to left and right turns on red. So is it also not legal to turn right on red, onto any sort of highway infrastructure, because they're not "streets"?? fuck off...
Quote from: RCW 46.61.055
vehicle operators facing a steady circular red/steady red arrow signal may, after stopping proceed to make a right turn from a one-way or two-way street into a two-way street or into a one-way street carrying traffic in the direction of the right turn; or a left turn from a one-way or two-way street into a one-way street carrying traffic in the direction of the left turn
If LTOR isn't legal onto an on-ramp, then, by the book, neither are right turns.
2) This left turn in Vancouver, onto an on-ramp, is marked with "no turn on red" signs, implying that the maneuver would be legal without the signs. Why would WSDOT install this sign, if the turn is illegal anyways?
Quote from: stevashe on October 26, 2019, 03:48:12 AM
Also Jake, I'd advise against bringing this up to WSDOT. From my limited interactions with them I'd expect them to sooner put up "No Turn on Red" signs at every on-ramp in the state than put in any red flashing arrows.
Based on my above image, I think WSDOT may be well-aware of the law. They just keep quiet about it.
Title: Re: Double left turns with permissive phasing
Post by: US 89 on October 27, 2019, 10:36:52 AM
Post by: US 89 on October 27, 2019, 10:36:52 AM
Quote from: jakeroot on October 27, 2019, 04:10:04 AM
2) This left turn in Vancouver, onto an on-ramp (https://goo.gl/maps/Ym3qqum4HWDKmpWM6), is marked with "no turn on red" signs, implying that the maneuver would be legal without the signs. Why would WSDOT install this sign, if the turn is illegal anyways?
That by itself doesn't mean a whole lot to me - WSDOT could just be playing it safe. As another example of this practice: in Utah you can't turn right at a red arrow, but almost all the red right arrows I know of are accompanied by a redundant NTOR sign, probably for the benefit of those who aren't aware that the movement is illegal anyway.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on October 27, 2019, 05:34:47 PM
Post by: jakeroot on October 27, 2019, 05:34:47 PM
Quote from: US 89 on October 27, 2019, 10:36:52 AMQuote from: jakeroot on October 27, 2019, 04:10:04 AM
2) This left turn in Vancouver, onto an on-ramp (https://goo.gl/maps/Ym3qqum4HWDKmpWM6), is marked with "no turn on red" signs, implying that the maneuver would be legal without the signs. Why would WSDOT install this sign, if the turn is illegal anyways?
That by itself doesn't mean a whole lot to me - WSDOT could just be playing it safe. As another example of this practice: in Utah you can't turn right at a red arrow, but almost all the red right arrows I know of are accompanied by a redundant NTOR sign, probably for the benefit of those who aren't aware that the movement is illegal anyway.
But remember that it would be legal without the sign. The sign is not redundant, even if WSDOT thought [momentarily] that it was. There's also no other examples of this sign, in this kind of situation (left turn onto a freeway ramp) anywhere else in the state, that I can recall. Or probably anywhere else in the country, that I can recall anyways. If they wanted to be redundant here, why not anywhere else?
Title: Re: Double left turns with permissive phasing
Post by: doorknob60 on November 01, 2019, 01:24:14 PM
Post by: doorknob60 on November 01, 2019, 01:24:14 PM
Quote from: jakeroot on October 27, 2019, 05:34:47 PMQuote from: US 89 on October 27, 2019, 10:36:52 AMQuote from: jakeroot on October 27, 2019, 04:10:04 AM
2) This left turn in Vancouver, onto an on-ramp (https://goo.gl/maps/Ym3qqum4HWDKmpWM6), is marked with "no turn on red" signs, implying that the maneuver would be legal without the signs. Why would WSDOT install this sign, if the turn is illegal anyways?
That by itself doesn’t mean a whole lot to me - WSDOT could just be playing it safe. As another example of this practice: in Utah you can’t turn right at a red arrow, but almost all the red right arrows I know of are accompanied by a redundant NTOR sign, probably for the benefit of those who aren’t aware that the movement is illegal anyway.
But remember that it would be legal without the sign. The sign is not redundant, even if WSDOT thought [momentarily] that it was. There's also no other examples of this sign, in this kind of situation (left turn onto a freeway ramp) anywhere else in the state, that I can recall. Or probably anywhere else in the country, that I can recall anyways. If they wanted to be redundant here, why not anywhere else?
I agree with everything you're saying and agree with your interpretation of the law, but I did find a redundant "no left on red" sign, from a two way street (though at its end at a T, and not a freeway ramp, for what it's worth), in Boise, ID. https://www.google.com/maps/@43.6199959,-116.2265304,3a,75y,160.97h,86.73t/data=!3m6!1e1!3m4!1sdy6V6BkaGQ0KjaXjxgQfJQ!2e0!7i13312!8i6656
It used to be allowed there (signal on the left lane was a red ball; the turn was actually banned from the right lane, see here (https://www.google.com/maps/@43.6200485,-116.2264126,3a,37.7y,192.03h,88.51t/data=!3m7!1e1!3m5!1sH6P_QFbY0kFV4iOGoCNKrQ!2e0!5s20150701T000000!7i13312!8i6656)), then they changed it to all red arrows (which bans the movement in Idaho, I'm aware it doesn't ban it in WA and OR) and later put up the signs, which are technically redundant. Though Idaho usually puts up signs in addition when red arrows are banning otherwise allowed turns (usually right turn on red).
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on January 06, 2020, 01:42:10 AM
Post by: fwydriver405 on January 06, 2020, 01:42:10 AM
Would this count as a permissive double left turn? Found this in Brunswick ME driving back from Orono yesterday...
Maine Street to US-1 North on-ramp in Brunswick, Maine (https://www.google.com/maps/@43.9179478,-69.9666226,3a,26.5y,153.64h,86.57t/data=!3m6!1e1!3m4!1s8-Z_nPQVXN4rFq_0trgHbg!2e0!7i16384!8i8192)
Flashing red arrows for the double left turns, and flashing yellow balls for the thru directions. There is no stop bar at this intersection and the left turning drivers treat it like a flashing yellow arrow...
Maine Street to US-1 North on-ramp in Brunswick, Maine (https://www.google.com/maps/@43.9179478,-69.9666226,3a,26.5y,153.64h,86.57t/data=!3m6!1e1!3m4!1s8-Z_nPQVXN4rFq_0trgHbg!2e0!7i16384!8i8192)
Flashing red arrows for the double left turns, and flashing yellow balls for the thru directions. There is no stop bar at this intersection and the left turning drivers treat it like a flashing yellow arrow...
Title: Re: Double left turns with permissive phasing
Post by: kphoger on January 06, 2020, 11:43:13 AM
Post by: kphoger on January 06, 2020, 11:43:13 AM
Quote from: fwydriver405 on January 06, 2020, 01:42:10 AM
Would this count as a permissive double left turn? Found this in Brunswick ME driving back from Orono yesterday...
Maine Street to US-1 North on-ramp in Brunswick, Maine (https://www.google.com/maps/@43.9179478,-69.9666226,3a,26.5y,153.64h,86.57t/data=!3m6!1e1!3m4!1s8-Z_nPQVXN4rFq_0trgHbg!2e0!7i16384!8i8192)
Flashing red arrows for the double left turns, and flashing yellow balls for the thru directions. There is no stop bar at this intersection and the left turning drivers treat it like a flashing yellow arrow...
That is weeeeeeeeird!
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 06, 2020, 02:06:39 PM
Post by: jakeroot on January 06, 2020, 02:06:39 PM
Quote from: fwydriver405 on January 06, 2020, 01:42:10 AM
Would this count as a permissive double left turn? Found this in Brunswick ME driving back from Orono yesterday...
Maine Street to US-1 North on-ramp in Brunswick, Maine (https://www.google.com/maps/@43.9179478,-69.9666226,3a,26.5y,153.64h,86.57t/data=!3m6!1e1!3m4!1s8-Z_nPQVXN4rFq_0trgHbg!2e0!7i16384!8i8192)
Flashing red arrows for the double left turns, and flashing yellow balls for the thru directions. There is no stop bar at this intersection and the left turning drivers treat it like a flashing yellow arrow...
Ian also posted this example (https://www.aaroads.com/forum/index.php?topic=24853.msg2447390#msg2447390) to the "Unsignalized Double Left Turns" thread.
Whether it's truly unsignalized or not, I don't know. But at any rate, it's definitely unusual. And I like it.
Title: Re: Double left turns with permissive phasing
Post by: kphoger on January 06, 2020, 02:11:46 PM
Post by: kphoger on January 06, 2020, 02:11:46 PM
Quote from: jakeroot on January 06, 2020, 02:06:39 PM
But at any rate, it's definitely unusual. And therefore I like it.
Edited for accuracy.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 06, 2020, 02:17:14 PM
Post by: jakeroot on January 06, 2020, 02:17:14 PM
Totally forgot to post this example that I found a few weeks ago:
Left turn from southbound Sarival Road to eastbound Northern Parkway (https://goo.gl/maps/9c1qjjV91BtFdSg99), outside Waddell, Arizona.
There are a few other permissive double lefts in the Phoenix area, and most are fairly old. Excluding those in places like Chandler, where the permissive phase never seems to activate, these are quite new and are effectively in permissive mode 100% of the time. I'm sure Maricopa County would install fully-protected left turns once Sarival Road is fully widened, and the Parkway's easterly extension is complete. But they probably realized how quiet the area would be until such point, so they installed five-section towers until then. Well done, Maricopa County.
Left turn from southbound Sarival Road to eastbound Northern Parkway (https://goo.gl/maps/9c1qjjV91BtFdSg99), outside Waddell, Arizona.
There are a few other permissive double lefts in the Phoenix area, and most are fairly old. Excluding those in places like Chandler, where the permissive phase never seems to activate, these are quite new and are effectively in permissive mode 100% of the time. I'm sure Maricopa County would install fully-protected left turns once Sarival Road is fully widened, and the Parkway's easterly extension is complete. But they probably realized how quiet the area would be until such point, so they installed five-section towers until then. Well done, Maricopa County.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 06, 2020, 02:18:32 PM
Post by: jakeroot on January 06, 2020, 02:18:32 PM
Quote from: kphoger on January 06, 2020, 02:11:46 PMQuote from: jakeroot on January 06, 2020, 02:06:39 PM
But at any rate, it's definitely unusual. And therefore I like it.
Edited for accuracy.
(https://media0.giphy.com/media/AaosjRHKjEcXm/giphy.gif)
Title: Re: Double left turns with permissive phasing
Post by: roadfro on January 08, 2020, 12:11:16 AM
Post by: roadfro on January 08, 2020, 12:11:16 AM
Quote from: jakeroot on January 06, 2020, 02:17:14 PM
Totally forgot to post this example that I found a few weeks ago:
Left turn from southbound Sarival Road to eastbound Northern Parkway (https://goo.gl/maps/9c1qjjV91BtFdSg99), outside Waddell, Arizona.
There are a few other permissive double lefts in the Phoenix area, and most are fairly old. Excluding those in places like Chandler, where the permissive phase never seems to activate, these are quite new and are effectively in permissive mode 100% of the time. I'm sure Maricopa County would install fully-protected left turns once Sarival Road is fully widened, and the Parkway's easterly extension is complete. But they probably realized how quiet the area would be until such point, so they installed five-section towers until then. Well done, Maricopa County.
This is interesting to me, as it's a dual permissive left setup at a seemingly under capacity intersection clearly built with future turning volumes in mind. The same intersection constructed in Nevada would likely have the inner turn lane blocked off with chevrons until demand necessitated its use, at the same time the permitted left would likely be removed for protected lefts.
EDIT: I don't know the volumes on Sarival Rd. But after looking at the intersection further and the movements currently existing, they probably could have gotten away with not activating this signal at all until future phases of Northern Pkwy open.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 08, 2020, 01:41:29 AM
Post by: jakeroot on January 08, 2020, 01:41:29 AM
Quote from: roadfro on January 08, 2020, 12:11:16 AMQuote from: jakeroot on January 06, 2020, 02:17:14 PM
Totally forgot to post this example that I found a few weeks ago:
Left turn from southbound Sarival Road to eastbound Northern Parkway (https://goo.gl/maps/9c1qjjV91BtFdSg99), outside Waddell, Arizona.
There are a few other permissive double lefts in the Phoenix area, and most are fairly old. Excluding those in places like Chandler, where the permissive phase never seems to activate, these are quite new and are effectively in permissive mode 100% of the time. I'm sure Maricopa County would install fully-protected left turns once Sarival Road is fully widened, and the Parkway's easterly extension is complete. But they probably realized how quiet the area would be until such point, so they installed five-section towers until then. Well done, Maricopa County.
This is interesting to me, as it's a dual permissive left setup at a seemingly under capacity intersection clearly built with future turning volumes in mind. The same intersection constructed in Nevada would likely have the inner turn lane blocked off with chevrons until demand necessitated its use, at the same time the permitted left would likely be removed for protected lefts.
EDIT: I don't know the volumes on Sarival Rd. But after looking at the intersection further and the movements currently existing, they probably could have gotten away with not activating this signal at all until future phases of Northern Pkwy open.
I think Washington State, and probably most other states, would have done the same. Judging by ADT numbers from Maricopa County, no section of Sarival Road averages more than ~1200 vehicles/day. Even if all of those cars turned onto Northern Pkwy, I doubt two left turn lanes is necessary.
With that said, I don't know about crash numbers. If there is no history of crashes at the intersection, it's not like two turn lanes hurts anything. Catch is, Arizona (apparently) doesn't make their crash data available for free. So I can't verify that claim. I can only assume, from imagery available from Street View, that the area is relatively quiet and likely doesn't not see many (if any) regular collisions.
Title: Re: Double left turns with permissive phasing
Post by: Roadwarriors79 on January 09, 2020, 01:06:18 AM
Post by: Roadwarriors79 on January 09, 2020, 01:06:18 AM
FWIW, the traffic signals at the Northern Parkway interchanges with Sarival Road, Reems Road, and Litchfield Road are all operated by the city of Glendale.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 09, 2020, 08:17:31 PM
Post by: jakeroot on January 09, 2020, 08:17:31 PM
Quote from: Roadwarriors79 on January 09, 2020, 01:06:18 AM
FWIW, the traffic signals at the Northern Parkway interchanges with Sarival Road, Reems Road, and Litchfield Road are all operated by the city of Glendale.
Thanks. I know the Northern Parkway is a Maricopa County project, but as with any locality, the management of the signals at the ramp termini varies.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on January 10, 2020, 03:54:53 PM
Post by: mrsman on January 10, 2020, 03:54:53 PM
Quote from: jakeroot on January 09, 2020, 08:17:31 PMQuote from: Roadwarriors79 on January 09, 2020, 01:06:18 AM
FWIW, the traffic signals at the Northern Parkway interchanges with Sarival Road, Reems Road, and Litchfield Road are all operated by the city of Glendale.
Thanks. I know the Northern Parkway is a Maricopa County project, but as with any locality, the management of the signals at the ramp termini varies.
This is definitely a case where they put in all the infrastructure necessary for the future in the present. While it may make some sense to do all of the work involved for the interchange, including widening Sarival, double left turn lanes, and the signal infrastructure, while they are working on the project - I don't see how having the traffic signal operating (including the usage of electricity) is justified until traffic levels increase, probably as the area gets more developed. In other areas, the signals would be off and covered until traffic picks up, with the use of temproary stop signs as needed.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on January 26, 2020, 06:11:52 PM
Post by: Amtrakprod on January 26, 2020, 06:11:52 PM
Cedar Ridge TX:
https://www.google.com/maps/@30.5090378,-97.7872553,3a,75y,182.83h,87.22t/data=!3m6!1e1!3m4!1sfjq8NdbIipcZ2HROPuFNiQ!2e0!7i16384!8i8192
Pedestrian phase dual permissive.
https://www.google.com/maps/@30.5090378,-97.7872553,3a,75y,182.83h,87.22t/data=!3m6!1e1!3m4!1sfjq8NdbIipcZ2HROPuFNiQ!2e0!7i16384!8i8192
Pedestrian phase dual permissive.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 26, 2020, 08:53:44 PM
Post by: jakeroot on January 26, 2020, 08:53:44 PM
Quote from: Amtrakprod on January 26, 2020, 06:11:52 PM
Cedar Ridge TX:
https://www.google.com/maps/@30.5090378,-97.7872553,3a,75y,182.83h,87.22t/data=!3m6!1e1!3m4!1sfjq8NdbIipcZ2HROPuFNiQ!2e0!7i16384!8i8192
Pedestrian phase dual permissive.
Good find. Usually in those circumstances, the crosswalk is against right-turning traffic. This is fairly unusual, but reminds me of this T-intersection (https://goo.gl/maps/u9NTfGXCjpCXoQZ99) in Vancouver, BC (double left yield to peds, no crosswalk along right edge).
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 31, 2020, 03:09:48 AM
Post by: jakeroot on January 31, 2020, 03:09:48 AM
According to the video below (jump to 0:35), W 1st @ Main in downtown Los Angeles used to be a double permissive left turn, with the outermost left turn being an optional left/straight lane. Main was a one-way going left, so there was no oncoming left turns:
https://www.youtube.com/watch?v=6a5xDAUNBUA&t=3s
The current intersection (https://goo.gl/maps/5Hv7sbZoq6F1fiMb6) has a single left turn lane, with no indication since Street View imagery began that it was removed anytime recently.
I really don't know of any in California at this point (not surprising given how conservative they are with permissive turns in general), but it's interesting to think that LA was even more liberal with left turns than they are now (very, compared to the rest of California).
https://www.youtube.com/watch?v=6a5xDAUNBUA&t=3s
The current intersection (https://goo.gl/maps/5Hv7sbZoq6F1fiMb6) has a single left turn lane, with no indication since Street View imagery began that it was removed anytime recently.
I really don't know of any in California at this point (not surprising given how conservative they are with permissive turns in general), but it's interesting to think that LA was even more liberal with left turns than they are now (very, compared to the rest of California).
Title: Re: Double left turns with permissive phasing
Post by: mrsman on February 03, 2020, 07:27:31 PM
Post by: mrsman on February 03, 2020, 07:27:31 PM
Quote from: jakeroot on January 31, 2020, 03:09:48 AM
According to the video below (jump to 0:35), W 1st @ Main in downtown Los Angeles used to be a double permissive left turn, with the outermost left turn being an optional left/straight lane. Main was a one-way going left, so there was no oncoming left turns:
https://www.youtube.com/watch?v=6a5xDAUNBUA&t=3s
The current intersection (https://goo.gl/maps/5Hv7sbZoq6F1fiMb6) has a single left turn lane, with no indication since Street View imagery began that it was removed anytime recently.
I really don't know of any in California at this point (not surprising given how conservative they are with permissive turns in general), but it's interesting to think that LA was even more liberal with left turns than they are now (very, compared to the rest of California).
Love the video. 13 year old me probably went through about half of those points at some point during the late 80's/early 90's.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on February 03, 2020, 07:38:09 PM
Post by: mrsman on February 03, 2020, 07:38:09 PM
Quote from: jakeroot on January 26, 2020, 08:53:44 PMQuote from: Amtrakprod on January 26, 2020, 06:11:52 PM
Cedar Ridge TX:
https://www.google.com/maps/@30.5090378,-97.7872553,3a,75y,182.83h,87.22t/data=!3m6!1e1!3m4!1sfjq8NdbIipcZ2HROPuFNiQ!2e0!7i16384!8i8192
Pedestrian phase dual permissive.
Good find. Usually in those circumstances, the crosswalk is against right-turning traffic. This is fairly unusual, but reminds me of this T-intersection (https://goo.gl/maps/u9NTfGXCjpCXoQZ99) in Vancouver, BC (double left yield to peds, no crosswalk along right edge).
While this is your thread Jake, I would prefer that examples like this not be included. There are probably many intersections out there with some form of double left that doesn't need to yield to vehicular traffic, but yields to pedestrians. Basically, T-intersections or one-way streets. But these are really different from situations where you would yield to vehicles in the way that you approach them.
If there is no opposing traffic, in what sense are you making a permissive turn? The turn is functionally equivalent to a right turn, as you have to watch for pedestrians, but during green ball phase you have no vehicles to watch out for.
In those situations, the vast majority will be turns with green ball (or perhaps FYA to highlight yielding to peds). Very few of this situation would involve a red arrow, protected only turn (such as very high pedestrian volume).
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 04, 2020, 03:53:59 AM
Post by: jakeroot on February 04, 2020, 03:53:59 AM
Quote from: mrsman on February 03, 2020, 07:38:09 PM
While this is your thread Jake, I would prefer that examples like this not be included. There are probably many intersections out there with some form of double left that doesn't need to yield to vehicular traffic, but yields to pedestrians. Basically, T-intersections or one-way streets. But these are really different from situations where you would yield to vehicles in the way that you approach them.
If there is no opposing traffic, in what sense are you making a permissive turn? The turn is functionally equivalent to a right turn, as you have to watch for pedestrians, but during green ball phase you have no vehicles to watch out for.
In those situations, the vast majority will be turns with green ball (or perhaps FYA to highlight yielding to peds). Very few of this situation would involve a red arrow, protected only turn (such as very high pedestrian volume).
No, it's good. You make a legitimate point. I'm sure they're far more common than regular dual-permissive left turns. I don't personally know of any that work this way in WA (all my local examples are from British Columbia), which is why I was initially fine with their inclusion. But all things considered, traffic control-wise, it's certainly not as interesting as a dual permissive left across traffic.
Nevertheless, if someone wanted to share a location where a traffic light works in this fashion, I'm not sure where else they'd post about it. Another reason I was fine with it. If I ran into one in Washington, I might have considered posting it here with the caveat that it's not a true "double permissive left turn" in the sense that there is no "oncoming" vehicular traffic.
Title: Re: Double left turns with permissive phasing
Post by: Revive 755 on February 05, 2020, 10:38:32 PM
Post by: Revive 755 on February 05, 2020, 10:38:32 PM
Quote from: roadfro on October 26, 2017, 08:52:47 AM
For those agencies that are hesitant about a dual permissive left, but need the capacity of dual lefts in the peak hour: I wonder if there's a way you could program a signal and adequately sign/stripe the intersection so that the second turn lane is used only in the peak hour during protected-only mode, but leave one lane for permitted lefts during non-peak hours...
Seems North Carolina is going to test this, per https://www.ncdot.gov/news/press-releases/Pages/2020/2020-02-05-dynamic-left-turn-intersection.aspx (https://www.ncdot.gov/news/press-releases/Pages/2020/2020-02-05-dynamic-left-turn-intersection.aspx)
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on February 06, 2020, 08:24:24 PM
Post by: Amtrakprod on February 06, 2020, 08:24:24 PM
Quote from: Revive 755 on February 05, 2020, 10:38:32 PMWas gonna post that.Quote from: roadfro on October 26, 2017, 08:52:47 AM
For those agencies that are hesitant about a dual permissive left, but need the capacity of dual lefts in the peak hour: I wonder if there's a way you could program a signal and adequately sign/stripe the intersection so that the second turn lane is used only in the peak hour during protected-only mode, but leave one lane for permitted lefts during non-peak hours...
Seems North Carolina is going to test this, per https://www.ncdot.gov/news/press-releases/Pages/2020/2020-02-05-dynamic-left-turn-intersection.aspx (https://www.ncdot.gov/news/press-releases/Pages/2020/2020-02-05-dynamic-left-turn-intersection.aspx)
iPhone
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 06, 2020, 11:07:38 PM
Post by: jakeroot on February 06, 2020, 11:07:38 PM
Quote from: Revive 755 on February 05, 2020, 10:38:32 PM
Seems North Carolina is going to test this, per https://www.ncdot.gov/news/press-releases/Pages/2020/2020-02-05-dynamic-left-turn-intersection.aspx (https://www.ncdot.gov/news/press-releases/Pages/2020/2020-02-05-dynamic-left-turn-intersection.aspx)
Certainly interested to see how well observed the closed lane will be, particularly among drivers who might pass through the intersection 95% of the time during peak hours (and would thus be used to dual-lane operation).
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on February 08, 2020, 08:22:04 AM
Post by: Amtrakprod on February 08, 2020, 08:22:04 AM
Check this one out in Austin:
https://www.google.com/maps/@30.2640864,-97.7473521,3a,15y,105.54h,94.25t/data=!3m6!1e1!3m4!1sRWXg6oGRRUJE-iDtfcOdMw!2e0!7i16384!8i8192
https://www.google.com/maps/@30.2640864,-97.7473521,3a,15y,105.54h,94.25t/data=!3m6!1e1!3m4!1sRWXg6oGRRUJE-iDtfcOdMw!2e0!7i16384!8i8192
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on February 08, 2020, 08:23:38 AM
Post by: Amtrakprod on February 08, 2020, 08:23:38 AM
and this one ish:
https://www.google.com/maps/@30.263465,-97.7445535,3a,69.1y,272.48h,92.44t/data=!3m6!1e1!3m4!1s7NkP_h9llho9Wl_j6sQfSQ!2e0!7i16384!8i8192
https://www.google.com/maps/@30.263465,-97.7445535,3a,69.1y,272.48h,92.44t/data=!3m6!1e1!3m4!1s7NkP_h9llho9Wl_j6sQfSQ!2e0!7i16384!8i8192
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 08, 2020, 02:40:12 PM
Post by: jakeroot on February 08, 2020, 02:40:12 PM
Quote from: Amtrakprod on February 08, 2020, 08:22:04 AM
Check this one out in Austin:
https://www.google.com/maps/@30.2640864,-97.7473521,3a,15y,105.54h,94.25t/data=!3m6!1e1!3m4!1sRWXg6oGRRUJE-iDtfcOdMw!2e0!7i16384!8i8192
That's a long one; I'm guessing lagging green arrows. Great find! Texas seems to have quite a few, but given the urban area and two-way traffic, I consider it thread-worthy.
Quote from: Amtrakprod on February 08, 2020, 08:23:38 AM
and this one ish:
https://www.google.com/maps/@30.263465,-97.7445535,3a,69.1y,272.48h,92.44t/data=!3m6!1e1!3m4!1s7NkP_h9llho9Wl_j6sQfSQ!2e0!7i16384!8i8192
This is the same link as before.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on February 08, 2020, 05:27:59 PM
Post by: Amtrakprod on February 08, 2020, 05:27:59 PM
I'm pretty sure it's a different link. Lemme try again:
https://www.google.com/maps/@30.2632756,-97.7443458,3a,15y,308.79h,91.64t/data=!3m6!1e1!3m4!1sd9fUTu96VCquggQIJrfisA!2e0!7i16384!8i8192
https://www.google.com/maps/@30.2632756,-97.7443458,3a,15y,308.79h,91.64t/data=!3m6!1e1!3m4!1sd9fUTu96VCquggQIJrfisA!2e0!7i16384!8i8192
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 08, 2020, 07:03:13 PM
Post by: jakeroot on February 08, 2020, 07:03:13 PM
Quote from: Amtrakprod on February 08, 2020, 05:27:59 PM
I'm pretty sure it's a different link. Lemme try again:
https://www.google.com/maps/@30.2632756,-97.7443458,3a,15y,308.79h,91.64t/data=!3m6!1e1!3m4!1sd9fUTu96VCquggQIJrfisA!2e0!7i16384!8i8192
Got it. Hard to tell what's going on. In this link (https://goo.gl/maps/RZASymzdinCgmWiY9), it looks like it might be split-phased when the double left turn is activated. Thinking this because there are cars waiting to turn at the double left (spin camera around), but no green arrow was afforded to them.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on February 08, 2020, 10:40:45 PM
Post by: Amtrakprod on February 08, 2020, 10:40:45 PM
it also has dallas phasing!
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 09, 2020, 03:26:46 PM
Post by: jakeroot on February 09, 2020, 03:26:46 PM
Quote from: Amtrakprod on February 08, 2020, 10:40:45 PM
it also has dallas phasing!
Are we sure? Because it could be split phasing. Dallas phasing can have that appearance, unless Google Street View shows (within the same set of images) a permissive mode, followed by a protected green arrow for only one of the movements. Seeing only one direction with a green arrow (at a typical 5-section display), when the other direction also has a ton of waiting cars, is either caused by one of the directions having a lagging protected green arrow (fully protected left turn), no protected turn at all, or (rarely) the intersection operating protective/permissive most of the time, and split-phased during other times.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on February 09, 2020, 05:45:32 PM
Post by: Amtrakprod on February 09, 2020, 05:45:32 PM
Quote from: jakeroot on February 09, 2020, 03:26:46 PMCheck out the 360 views here. it's not in the split phase phase.Quote from: Amtrakprod on February 08, 2020, 10:40:45 PM
it also has dallas phasing!
Are we sure? Because it could be split phasing. Dallas phasing can have that appearance, unless Google Street View shows (within the same set of images) a permissive mode, followed by a protected green arrow for only one of the movements. Seeing only one direction with a green arrow (at a typical 5-section display), when the other direction also has a ton of waiting cars, is either caused by one of the directions having a lagging protected green arrow (fully protected left turn), no protected turn at all, or (rarely) the intersection operating protective/permissive most of the time, and split-phased during other times.
https://www.google.com/maps/@30.2633489,-97.7445113,3a,15y,97.94h,98.25t/data=!3m6!1e1!3m4!1sK-JcQoBYswEgWMahpYmrAQ!2e0!7i13312!8i6656
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 09, 2020, 06:16:57 PM
Post by: jakeroot on February 09, 2020, 06:16:57 PM
Quote from: Amtrakprod on February 09, 2020, 05:45:32 PMQuote from: jakeroot on February 09, 2020, 03:26:46 PMCheck out the 360 views here. it's not in the split phase phase.Quote from: Amtrakprod on February 08, 2020, 10:40:45 PM
it also has dallas phasing!
Are we sure? Because it could be split phasing. Dallas phasing can have that appearance, unless Google Street View shows (within the same set of images) a permissive mode, followed by a protected green arrow for only one of the movements. Seeing only one direction with a green arrow (at a typical 5-section display), when the other direction also has a ton of waiting cars, is either caused by one of the directions having a lagging protected green arrow (fully protected left turn), no protected turn at all, or (rarely) the intersection operating protective/permissive most of the time, and split-phased during other times.
https://www.google.com/maps/@30.2633489,-97.7445113,3a,15y,97.94h,98.25t/data=!3m6!1e1!3m4!1sK-JcQoBYswEgWMahpYmrAQ!2e0!7i13312!8i6656
Oh, yeah. You can see it pretty clearly here too (https://goo.gl/maps/h1szkdCPJbpU5WCq9). Of course, it's operating that way during the single-left-turn mode.
I did a bit more sleuthing. Look at this image from Sep 2016 (https://goo.gl/maps/SLbqoVReu2xSWY2j9); if you look at the traffic waiting across from the Street View car, we can see a Chevy Tahoe or Suburban, as well as a 1st-gen Ford Fusion. To our right, we can see a whole load of cars waiting to proceed straight. There's also two guys walking southbound on Congress way off to the left, and a runner going eastbound along Cesar Chavez (behind, left).
Now, jump ahead one click to follow the camera car (https://goo.gl/maps/47BDmi7urPCSCBAk8) through the left turn. First, note that westbound Cesar Chavez has a red light while our left turn has a green arrow. The cars that were to our right have set off (you can see most of them well ahead at the next signal or approaching it); the two guys walking are waiting at the corner; the runner has crossed Cesar Chavez by about five car-lengths; there's other stuff too, I'm sure. But what has changed is the oncoming cars: all of them are completely different.
Note that the camera car has not made any progress relative to most of the cars that were originally to the right. This tells me that the Street View vehicle started with a solid green (yield signal), while traffic to its right proceeded off. But by the time the image was taken, the green arrow had activated for our left turn, indicating a lagging green arrow. But there is no yellow trap for one important reason: apparently, when that double left turn was installed, a fourth signal was installed on the mast (https://goo.gl/maps/nST5iSKUUKDBFRFv7). It appears that, during some hours, they run the double left turn from the 5-section signals as a protected-only turn, and the two three-section signals (one overhead, one on mast) become the through signals.
That was really hard to explain; I hope it makes some sense.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on February 09, 2020, 07:01:45 PM
Post by: Amtrakprod on February 09, 2020, 07:01:45 PM
Quote from: jakeroot on February 09, 2020, 06:16:57 PMQuote from: Amtrakprod on February 09, 2020, 05:45:32 PMQuote from: jakeroot on February 09, 2020, 03:26:46 PMCheck out the 360 views here. it's not in the split phase phase.Quote from: Amtrakprod on February 08, 2020, 10:40:45 PM
it also has dallas phasing!
Are we sure? Because it could be split phasing. Dallas phasing can have that appearance, unless Google Street View shows (within the same set of images) a permissive mode, followed by a protected green arrow for only one of the movements. Seeing only one direction with a green arrow (at a typical 5-section display), when the other direction also has a ton of waiting cars, is either caused by one of the directions having a lagging protected green arrow (fully protected left turn), no protected turn at all, or (rarely) the intersection operating protective/permissive most of the time, and split-phased during other times.
https://www.google.com/maps/@30.2633489,-97.7445113,3a,15y,97.94h,98.25t/data=!3m6!1e1!3m4!1sK-JcQoBYswEgWMahpYmrAQ!2e0!7i13312!8i6656
Oh, yeah. You can see it pretty clearly here too (https://goo.gl/maps/h1szkdCPJbpU5WCq9). Of course, it's operating that way during the single-left-turn mode.
I did a bit more sleuthing. Look at this image from Sep 2016 (https://goo.gl/maps/SLbqoVReu2xSWY2j9); if you look at the traffic waiting across from the Street View car, we can see a Chevy Tahoe or Suburban, as well as a 1st-gen Ford Fusion. To our right, we can see a whole load of cars waiting to proceed straight. There's also two guys walking southbound on Congress way off to the left, and a runner going eastbound along Cesar Chavez (behind, left).
Now, jump ahead one click to follow the camera car (https://goo.gl/maps/47BDmi7urPCSCBAk8) through the left turn. First, note that westbound Cesar Chavez has a red light while our left turn has a green arrow. The cars that were to our right have set off (you can see most of them well ahead at the next signal or approaching it); the two guys walking are waiting at the corner; the runner has crossed Cesar Chavez by about five car-lengths; there's other stuff too, I'm sure. But what has changed is the oncoming cars: all of them are completely different.
Note that the camera car has not made any progress relative to most of the cars that were originally to the right. This tells me that the Street View vehicle started with a solid green (yield signal), while traffic to its right proceeded off. But by the time the image was taken, the green arrow had activated for our left turn, indicating a lagging green arrow. But there is no yellow trap for one important reason: apparently, when that double left turn was installed, a fourth signal was installed on the mast (https://goo.gl/maps/nST5iSKUUKDBFRFv7). It appears that, during some hours, they run the double left turn from the 5-section signals as a protected-only turn, and the two three-section signals (one overhead, one on mast) become the through signals.
That was really hard to explain; I hope it makes some sense.
I understand this:
During peak periods, when the lane control lane is a left turn only, it operates in a split phase. During off-peak hours, it uses Dallas phasing and the lane control lane is straight only, to prevent double left turn permissive.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 09, 2020, 08:11:35 PM
Post by: jakeroot on February 09, 2020, 08:11:35 PM
Quote from: Amtrakprod on February 09, 2020, 07:01:45 PM
I understand this:
During peak periods, when the lane control lane is a left turn only, it operates in a split phase. During off-peak hours, it uses Dallas phasing and the lane control lane is straight only, to prevent double left turn permissive.
Actually, what I'm thinking is that the left turns operate as lead/lag during peak hours, but the double left turn is protected-only during these peak hours. This is evidenced by the extra through signal that was installed; when the two left turn signals are red, there are still two through signals for the straight-ahead movement along Cesar Chavez.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on February 09, 2020, 09:36:22 PM
Post by: Amtrakprod on February 09, 2020, 09:36:22 PM
I still think the Lead-Lag is midday because of the sun's position:
https://www.google.com/maps/@30.2633489,-97.7445113,3a,66.7y,210.93h,129.85t/data=!3m6!1e1!3m4!1sK-JcQoBYswEgWMahpYmrAQ!2e0!7i13312!8i6656
https://www.google.com/maps/@30.2633489,-97.7445113,3a,66.7y,210.93h,129.85t/data=!3m6!1e1!3m4!1sK-JcQoBYswEgWMahpYmrAQ!2e0!7i13312!8i6656
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on February 09, 2020, 09:43:45 PM
Post by: Amtrakprod on February 09, 2020, 09:43:45 PM
https://www.google.com/maps/@30.2633509,-97.7445162,3a,25.4y,318.47h,96.02t/data=!3m7!1e1!3m5!1svZNy0kdk4G8v9WqEOfk0-g!2e0!5s20170101T000000!7i13312!8i6656
Woah! The cycle isn't split phased! It's Protected left!
Woah! The cycle isn't split phased! It's Protected left!
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 09, 2020, 10:12:13 PM
Post by: jakeroot on February 09, 2020, 10:12:13 PM
Quote from: Amtrakprod on February 09, 2020, 09:43:45 PM
https://www.google.com/maps/@30.2633509,-97.7445162,3a,25.4y,318.47h,96.02t/data=!3m7!1e1!3m5!1svZNy0kdk4G8v9WqEOfk0-g!2e0!5s20170101T000000!7i13312!8i6656
Woah! The cycle isn't split phased! It's Protected left!
Right, right. That's what I was saying:
Quote from: jakeroot on February 09, 2020, 08:11:35 PM
what I'm thinking is that the left turns operate as lead/lag during peak hours, but the double left turn is protected-only during these peak hours. This is evidenced by the extra through signal that was installed; when the two left turn signals are red, there are still two through signals for the straight-ahead movement along Cesar Chavez.
Title: Re: Double left turns with permissive phasing
Post by: stevashe on February 09, 2020, 11:14:52 PM
Post by: stevashe on February 09, 2020, 11:14:52 PM
Quote from: jakeroot on February 04, 2020, 03:53:59 AMQuote from: mrsman on February 03, 2020, 07:38:09 PM
While this is your thread Jake, I would prefer that examples like this not be included. There are probably many intersections out there with some form of double left that doesn't need to yield to vehicular traffic, but yields to pedestrians. Basically, T-intersections or one-way streets. But these are really different from situations where you would yield to vehicles in the way that you approach them.
If there is no opposing traffic, in what sense are you making a permissive turn? The turn is functionally equivalent to a right turn, as you have to watch for pedestrians, but during green ball phase you have no vehicles to watch out for.
In those situations, the vast majority will be turns with green ball (or perhaps FYA to highlight yielding to peds). Very few of this situation would involve a red arrow, protected only turn (such as very high pedestrian volume).
No, it's good. You make a legitimate point. I'm sure they're far more common than regular dual-permissive left turns. I don't personally know of any that work this way in WA (all my local examples are from British Columbia), which is why I was initially fine with their inclusion. But all things considered, traffic control-wise, it's certainly not as interesting as a dual permissive left across traffic.
Nevertheless, if someone wanted to share a location where a traffic light works in this fashion, I'm not sure where else they'd post about it. Another reason I was fine with it. If I ran into one in Washington, I might have considered posting it here with the caveat that it's not a true "double permissive left turn" in the sense that there is no "oncoming" vehicular traffic.
Bit late to reply on this, but given a strict reading of the thread's title, a left turn against a crosswalk displaying the walk signal would count. While I agree that it is quite a different in operation due to not needing to yield to opposing traffic, in Traffic Engineering terms this is still considered a permitted/permissive left turn. In fact, the "normal" right turn you mention is also considered a permitted right. (A protected right with a green arrow requires both crosswalks to be Don't Walk and is usually shown with the opposing protected left.)
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on February 11, 2020, 02:44:28 PM
Post by: Amtrakprod on February 11, 2020, 02:44:28 PM
Quote from: stevashe on February 09, 2020, 11:14:52 PMAgreedQuote from: jakeroot on February 04, 2020, 03:53:59 AMQuote from: mrsman on February 03, 2020, 07:38:09 PM
While this is your thread Jake, I would prefer that examples like this not be included. There are probably many intersections out there with some form of double left that doesn't need to yield to vehicular traffic, but yields to pedestrians. Basically, T-intersections or one-way streets. But these are really different from situations where you would yield to vehicles in the way that you approach them.
If there is no opposing traffic, in what sense are you making a permissive turn? The turn is functionally equivalent to a right turn, as you have to watch for pedestrians, but during green ball phase you have no vehicles to watch out for.
In those situations, the vast majority will be turns with green ball (or perhaps FYA to highlight yielding to peds). Very few of this situation would involve a red arrow, protected only turn (such as very high pedestrian volume).
No, it's good. You make a legitimate point. I'm sure they're far more common than regular dual-permissive left turns. I don't personally know of any that work this way in WA (all my local examples are from British Columbia), which is why I was initially fine with their inclusion. But all things considered, traffic control-wise, it's certainly not as interesting as a dual permissive left across traffic.
Nevertheless, if someone wanted to share a location where a traffic light works in this fashion, I'm not sure where else they'd post about it. Another reason I was fine with it. If I ran into one in Washington, I might have considered posting it here with the caveat that it's not a true "double permissive left turn" in the sense that there is no "oncoming" vehicular traffic.
Bit late to reply on this, but given a strict reading of the thread's title, a left turn against a crosswalk displaying the walk signal would count. While I agree that it is quite a different in operation due to not needing to yield to opposing traffic, in Traffic Engineering terms this is still considered a permitted/permissive left turn. In fact, the "normal" right turn you mention is also considered a permitted right. (A protected right with a green arrow requires both crosswalks to be Don't Walk and is usually shown with the opposing protected left.)
iPhone
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 11, 2020, 04:01:09 PM
Post by: jakeroot on February 11, 2020, 04:01:09 PM
Quote from: stevashe on February 09, 2020, 11:14:52 PMQuote from: jakeroot on February 04, 2020, 03:53:59 AMQuote from: mrsman on February 03, 2020, 07:38:09 PM
While this is your thread Jake, I would prefer that examples like this not be included. There are probably many intersections out there with some form of double left that doesn't need to yield to vehicular traffic, but yields to pedestrians. Basically, T-intersections or one-way streets. But these are really different from situations where you would yield to vehicles in the way that you approach them.
If there is no opposing traffic, in what sense are you making a permissive turn? The turn is functionally equivalent to a right turn, as you have to watch for pedestrians, but during green ball phase you have no vehicles to watch out for.
In those situations, the vast majority will be turns with green ball (or perhaps FYA to highlight yielding to peds). Very few of this situation would involve a red arrow, protected only turn (such as very high pedestrian volume).
No, it's good. You make a legitimate point. I'm sure they're far more common than regular dual-permissive left turns. I don't personally know of any that work this way in WA (all my local examples are from British Columbia), which is why I was initially fine with their inclusion. But all things considered, traffic control-wise, it's certainly not as interesting as a dual permissive left across traffic.
Nevertheless, if someone wanted to share a location where a traffic light works in this fashion, I'm not sure where else they'd post about it. Another reason I was fine with it. If I ran into one in Washington, I might have considered posting it here with the caveat that it's not a true "double permissive left turn" in the sense that there is no "oncoming" vehicular traffic.
Bit late to reply on this, but given a strict reading of the thread's title, a left turn against a crosswalk displaying the walk signal would count. While I agree that it is quite a different in operation due to not needing to yield to opposing traffic, in Traffic Engineering terms this is still considered a permitted/permissive left turn. In fact, the "normal" right turn you mention is also considered a permitted right. (A protected right with a green arrow requires both crosswalks to be Don't Walk and is usually shown with the opposing protected left.)
Here I am being late myself.
My original idea with creating this thread was to discuss this style of phasing, not exactly to list each example. But that's what ended up coming from that, and that's totally cool because there really should be a database of these for future study.
At any rate, I think what makes oncoming vehicles more interesting is that they are approaching at various speeds, with varying gaps, and require drivers to give a bit more thought than yielding to pedestrians (who, walking, all travel around the same speed and are certainly less dangerous to cars than the other way around). There is still something very interesting about double left turns yielding to pedestrians, as they are decidedly quite rare, but they are a bit more mundane compared to left turns where yielding to pedestrians and vehicles is required.
Now, in light of there not being a thread for listing those situations, I am fine with them being posted here. It's just that they weren't in the original spirit of the thread (which I had in my head as being "against traffic" but didn't necessarily specify, beyond the listed examples thus far all being against traffic).
Title: Re: Double left turns with permissive phasing
Post by: mrsman on February 13, 2020, 01:17:07 AM
Post by: mrsman on February 13, 2020, 01:17:07 AM
Quote from: jakeroot on February 11, 2020, 04:01:09 PMQuote from: stevashe on February 09, 2020, 11:14:52 PMQuote from: jakeroot on February 04, 2020, 03:53:59 AMQuote from: mrsman on February 03, 2020, 07:38:09 PM
While this is your thread Jake, I would prefer that examples like this not be included. There are probably many intersections out there with some form of double left that doesn't need to yield to vehicular traffic, but yields to pedestrians. Basically, T-intersections or one-way streets. But these are really different from situations where you would yield to vehicles in the way that you approach them.
If there is no opposing traffic, in what sense are you making a permissive turn? The turn is functionally equivalent to a right turn, as you have to watch for pedestrians, but during green ball phase you have no vehicles to watch out for.
In those situations, the vast majority will be turns with green ball (or perhaps FYA to highlight yielding to peds). Very few of this situation would involve a red arrow, protected only turn (such as very high pedestrian volume).
No, it's good. You make a legitimate point. I'm sure they're far more common than regular dual-permissive left turns. I don't personally know of any that work this way in WA (all my local examples are from British Columbia), which is why I was initially fine with their inclusion. But all things considered, traffic control-wise, it's certainly not as interesting as a dual permissive left across traffic.
Nevertheless, if someone wanted to share a location where a traffic light works in this fashion, I'm not sure where else they'd post about it. Another reason I was fine with it. If I ran into one in Washington, I might have considered posting it here with the caveat that it's not a true "double permissive left turn" in the sense that there is no "oncoming" vehicular traffic.
Bit late to reply on this, but given a strict reading of the thread's title, a left turn against a crosswalk displaying the walk signal would count. While I agree that it is quite a different in operation due to not needing to yield to opposing traffic, in Traffic Engineering terms this is still considered a permitted/permissive left turn. In fact, the "normal" right turn you mention is also considered a permitted right. (A protected right with a green arrow requires both crosswalks to be Don't Walk and is usually shown with the opposing protected left.)
Here I am being late myself.
My original idea with creating this thread was to discuss this style of phasing, not exactly to list each example. But that's what ended up coming from that, and that's totally cool because there really should be a database of these for future study.
At any rate, I think what makes oncoming vehicles more interesting is that they are approaching at various speeds, with varying gaps, and require drivers to give a bit more thought than yielding to pedestrians (who, walking, all travel around the same speed and are certainly less dangerous to cars than the other way around). There is still something very interesting about double left turns yielding to pedestrians, as they are decidedly quite rare, but they are a bit more mundane compared to left turns where yielding to pedestrians and vehicles is required.
Now, in light of there not being a thread for listing those situations, I am fine with them being posted here. It's just that they weren't in the original spirit of the thread (which I had in my head as being "against traffic" but didn't necessarily specify, beyond the listed examples thus far all being against traffic).
What makes specific examples interesting is the extent that they are exceptions to a rule. And to the exent that they are exceptions, we try to discuss why they are present and what circumstances would lead to their being exceptions to the rule.
In most cases when you have a two-way street with a double left turn lane, the vast majority of cases will have a protected only left turn set up. Left turn permitted only with a protected left turn arrow, and left turns not permitted when opposing traffic has green. Exceptions to that occur in certain more liberal jurisdictions (like Tucson), or in situations where there are unusually good sight lines, especially if opposing lefts are also prohibited. These generally provide for a protected left, but also allow for left turns to be made during the phase of opposing traffic as well. These are interesting as they vary from the expectation. These are the main subject of this thread.
A special subset of the above can also occur without provision of any left turn protection at all and sometimes even without signals at all. You still have two left turn lanes that can turn left at times other than the protected phase. Also very unique.
With a dual left turn, where one is an option straight/left lane, the expectation is also generally a protected only turn, but for the most part, these present as split-phased signals (to avoid blocking straight traffic on green ball lights). Split-phase is a special example of protected left turn. To the extent that any of these signals are designed to allow a permitted turn while opposing traffic has right of way is also a special exception worthy of discussion (like 1st/Main in L.A. in the 1980's as Jake posted recently).
A dual left turn from a one way street to a one way street does not face opposing traffic other than pedestrians. Yes, you have to yield to pedestrians so in a technical sense it is a permitted turn. But the vast majority of these intersections permit the turn at all times. Occasionally, there may be signage (or state law) prohibiting turn on red [or prohibiting turn on red from the rightmost left turn lane]. But it is extremely rare to find a left from one way to one way that doesn't allow the turn during green ball phase. In fact, most of these do not even provide any protected left turn at all. A left turn on arrow only setup is rare and generally only present in very heavy pedestrian crossings or in the presence of protected bike lanes.
Here is an example of a left turn lane and left turn option lane from one way to one way controlled only by regular signal in Downtown Sacramento. Left turns are even permitted from both lanes on red signal. Signage reminds drivers that are turning to yield to pedestrians. Even in a downtown with a significant (but not extreme) level of pedestrian activity, no protected left is provided. Examples like this abound in Sacramento and many other cities. A protected left turn in this situation is quite rare. Those are more noteworthy than the protected/permitted left in such a case.
https://www.google.com/maps/@38.5822031,-121.5004067,3a,75y,100.9h,79.31t/data=!3m6!1e1!3m4!1sOeDqLTJ1MZbCgX-xsfn4Yg!2e0!7i13312!8i6656
Here's a similar example in Baltimore. No turn on red, and perhaps a leading pedestrain interval, but left turns are permitted without a protected left:
https://www.google.com/maps/@39.2874062,-76.6232488,3a,75y,254.33h,80.99t/data=!3m6!1e1!3m4!1sYB0-4vXZRCqp9CADR9Lozg!2e0!7i13312!8i6656
Similarly with T-interesections. If one street ends at another at a T-intersection where the terminating street has two left turn lanes, we expect the left turn to be permitted at all times that the signal is green, even if there is a pedestrian crossing. A left turn on arrow only situation is more rare, usually only used with heavy pedestrian crossings or a bike lane setup or some other unusual hazard.
Here's an example in Los Angeles, Century Park W at Olympic:
https://www.google.com/maps/@34.0532311,-118.4163626,3a,75y,114.07h,76.99t/data=!3m7!1e1!3m5!1segXAI0GciMXMGOBcJb9X7g!2e0!6s%2F%2Fgeo2.ggpht.com%2Fcbk%3Fpanoid%3DegXAI0GciMXMGOBcJb9X7g%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D305.7235%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192
Again, I don't find any of these above examples noteworthy since they don't defy the expectation. The expectation is that in situations with dual left turn lanes that only need to yield to a pedestrian crossing (and not uncoming vehicles), left turns are allowed during the permitted phase and protected lefts aren't generally even provided.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 24, 2020, 03:13:05 PM
Post by: jakeroot on February 24, 2020, 03:13:05 PM
Found another in Chicago: https://goo.gl/maps/Zn42Wji2djFMVPdd9
This brings the Chicago area tothree four known installations:
N Sheridan Road @ W Bryn Mawr Ave (https://goo.gl/maps/8DEpRwMKMZ8tc3EK7) (option lane)
N Columbus Drive (NB) @ E Grand Ave (https://goo.gl/maps/Zn42Wji2djFMVPdd9) (former option lane, now two dedicated turns) (NEW)
N Columbus Drive (SB) @ E Illinois Street (https://goo.gl/maps/Zu7i8GP8ij2q6kKg9) (former option lane, now two dedicated turns) (NEW)
Thorndale Ave @ Park Blvd, Itasca (https://goo.gl/maps/SZSFA9SQdQVQ5JJM9) (true double left) (removed, now an off-ramp from the 390 Toll Road)
This brings the Chicago area to
N Sheridan Road @ W Bryn Mawr Ave (https://goo.gl/maps/8DEpRwMKMZ8tc3EK7) (option lane)
N Columbus Drive (NB) @ E Grand Ave (https://goo.gl/maps/Zn42Wji2djFMVPdd9) (former option lane, now two dedicated turns) (NEW)
N Columbus Drive (SB) @ E Illinois Street (https://goo.gl/maps/Zu7i8GP8ij2q6kKg9) (former option lane, now two dedicated turns) (NEW)
Thorndale Ave @ Park Blvd, Itasca (https://goo.gl/maps/SZSFA9SQdQVQ5JJM9) (true double left) (removed, now an off-ramp from the 390 Toll Road)
Title: Re: Double left turns with permissive phasing
Post by: deathtopumpkins on February 25, 2020, 08:37:26 AM
Post by: deathtopumpkins on February 25, 2020, 08:37:26 AM
If you turn around in that new one you'll find another: Columbus SB @ Illinois St
There MAY also be another in Chicago on Sheridan at Devon: https://goo.gl/maps/zTfUKoWth4HEGsUW7
I can't recall the phasing off the top of my head, and Streetview is inconclusive, but I suspect it may just be split phased.
There MAY also be another in Chicago on Sheridan at Devon: https://goo.gl/maps/zTfUKoWth4HEGsUW7
I can't recall the phasing off the top of my head, and Streetview is inconclusive, but I suspect it may just be split phased.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 25, 2020, 01:50:42 PM
Post by: jakeroot on February 25, 2020, 01:50:42 PM
Quote from: deathtopumpkins on February 25, 2020, 08:37:26 AM
If you turn around in that new one you'll find another: Columbus SB @ Illinois St
There MAY also be another in Chicago on Sheridan at Devon: https://goo.gl/maps/zTfUKoWth4HEGsUW7
I can't recall the phasing off the top of my head, and Streetview is inconclusive, but I suspect it may just be split phased.
Guess I need to look around a bit more! Thanks for that fourth one.
The one at Devon looks to be split-phased. Old imagery shows both directions with 4-section signals, which (from what I can tell) are only used in Illinois at split-phased intersections or one-way streets.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on March 02, 2020, 09:29:01 PM
Post by: Amtrakprod on March 02, 2020, 09:29:01 PM
These setups are ALL OVER in TX along I35.
https://www.google.com/maps/@29.4388701,-98.4505458,3a,75y,194.04h,84.4t/data=!3m6!1e1!3m4!1sNj5vp60yDorsCzV_1agVpw!2e0!7i16384!8i8192
https://www.google.com/maps/@29.5102392,-98.3973887,3a,75y,78.86h,90.08t/data=!3m6!1e1!3m4!1sUplL-Jex1X2S_FepM8GBJA!2e0!7i16384!8i8192
https://www.google.com/maps/@29.5400891,-98.3792572,3a,66.8y,11.44h,85.27t/data=!3m6!1e1!3m4!1sJ-qXMICqvlIdN_BAbKOQgw!2e0!7i16384!8i8192
https://www.google.com/maps/@29.552288,-98.3554288,3a,33.9y,340.29h,91.59t/data=!3m6!1e1!3m4!1s0oTChvoS5crsnfABISmdSA!2e0!7i16384!8i8192
https://www.google.com/maps/@29.6002848,-98.2770688,3a,39.6y,321.97h,91.74t/data=!3m6!1e1!3m4!1sQw_svlCdMGP4rMIFgyW2WQ!2e0!7i16384!8i8192
And this!!!!
https://www.google.com/maps/@29.4387288,-98.4609631,3a,31.7y,3.23h,91.26t/data=!3m6!1e1!3m4!1sEnNKghe8vkX2j_TSRMDKgw!2e0!7i16384!8i8192
Flashing yellow arrow and doghouse combo! Shared permissive left turn lanes are strange but common out here!
https://www.google.com/maps/@29.4388701,-98.4505458,3a,75y,194.04h,84.4t/data=!3m6!1e1!3m4!1sNj5vp60yDorsCzV_1agVpw!2e0!7i16384!8i8192
https://www.google.com/maps/@29.5102392,-98.3973887,3a,75y,78.86h,90.08t/data=!3m6!1e1!3m4!1sUplL-Jex1X2S_FepM8GBJA!2e0!7i16384!8i8192
https://www.google.com/maps/@29.5400891,-98.3792572,3a,66.8y,11.44h,85.27t/data=!3m6!1e1!3m4!1sJ-qXMICqvlIdN_BAbKOQgw!2e0!7i16384!8i8192
https://www.google.com/maps/@29.552288,-98.3554288,3a,33.9y,340.29h,91.59t/data=!3m6!1e1!3m4!1s0oTChvoS5crsnfABISmdSA!2e0!7i16384!8i8192
https://www.google.com/maps/@29.6002848,-98.2770688,3a,39.6y,321.97h,91.74t/data=!3m6!1e1!3m4!1sQw_svlCdMGP4rMIFgyW2WQ!2e0!7i16384!8i8192
And this!!!!
https://www.google.com/maps/@29.4387288,-98.4609631,3a,31.7y,3.23h,91.26t/data=!3m6!1e1!3m4!1sEnNKghe8vkX2j_TSRMDKgw!2e0!7i16384!8i8192
Flashing yellow arrow and doghouse combo! Shared permissive left turn lanes are strange but common out here!
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 02, 2020, 10:40:26 PM
Post by: jakeroot on March 02, 2020, 10:40:26 PM
In terms of states with the most number of these, Texas and Colorado might be the leaders. Both are the only states that I've seen that seem to not only permit it, but actively encourage it.
The reason that neither state is mentioned in this list is simply because there are too many to list. Colorado was the first place I saw the setup, and I saw many in Texas when I was there in 2013.
As an example from Colorado, one needs only to take a glance around Castle Rock. At least 90% of their double left turns use permissive phasing (and there are a lot of them). And it's not like they're relics of the past; basically all of them are FYA installations that mostly date from the last 10 years (many which replaced double-doghouse setups).
The reason that neither state is mentioned in this list is simply because there are too many to list. Colorado was the first place I saw the setup, and I saw many in Texas when I was there in 2013.
As an example from Colorado, one needs only to take a glance around Castle Rock. At least 90% of their double left turns use permissive phasing (and there are a lot of them). And it's not like they're relics of the past; basically all of them are FYA installations that mostly date from the last 10 years (many which replaced double-doghouse setups).
Title: Re: Double left turns with permissive phasing
Post by: Revive 755 on March 02, 2020, 10:58:51 PM
Post by: Revive 755 on March 02, 2020, 10:58:51 PM
Quote from: jakeroot on February 25, 2020, 01:50:42 PM
The one at Devon looks to be split-phased. Old imagery shows both directions with 4-section signals, which (from what I can tell) are only used in Illinois at split-phased intersections or one-way streets.
Rockford has plenty of four sections with bimodal arrows for left turns. The Chicagoland IDOT District doesn't allow them, but since Chicago doesn't follow a lot of IDOT's policies (or the national MUTCD either) anyway . . .
Quote from: jakeroot on February 24, 2020, 03:13:05 PM
Found another in Chicago: https://goo.gl/maps/Zn42Wji2djFMVPdd9
This brings the Chicago area tothreefour known installations:
N Sheridan Road @ W Bryn Mawr Ave (https://goo.gl/maps/8DEpRwMKMZ8tc3EK7) (option lane)
N Columbus Drive (NB) @ E Grand Ave (https://goo.gl/maps/Zn42Wji2djFMVPdd9) (former option lane, now two dedicated turns) (NEW)
N Columbus Drive (SB) @ E Illinois Street (https://goo.gl/maps/Zu7i8GP8ij2q6kKg9) (former option lane, now two dedicated turns) (NEW)
Thorndale Ave @ Park Blvd, Itasca (https://goo.gl/maps/SZSFA9SQdQVQ5JJM9) (true double left) (removed, now an off-ramp from the 390 Toll Road)
NB Sunset Ridge Road at Skokie Boulevard in Northbrook, IL (https://goo.gl/maps/y7wNqM5fJajUkXXT7) used to have one (left + left-thru-right)
Did Joliet Street at Cass Street in downtown Joliet get removed? (https://goo.gl/maps/LSegLmDAYmpL2kmJA) (left + left-thru)
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 03, 2020, 01:53:01 AM
Post by: jakeroot on March 03, 2020, 01:53:01 AM
Quote from: Revive 755 on March 02, 2020, 10:58:51 PMQuote from: jakeroot on February 25, 2020, 01:50:42 PM
The one at Devon looks to be split-phased. Old imagery shows both directions with 4-section signals, which (from what I can tell) are only used in Illinois at split-phased intersections or one-way streets.
Rockford has plenty of four sections with bimodal arrows for left turns. The Chicagoland IDOT District doesn't allow them, but since Chicago doesn't follow a lot of IDOT's policies (or the national MUTCD either) anyway . . .
Good to know. Did not realize that bimodal signals were used in Illinois in any capacity.
Quote from: Revive 755 on March 02, 2020, 10:58:51 PMQuote from: jakeroot on February 24, 2020, 03:13:05 PM
Found another in Chicago: https://goo.gl/maps/Zn42Wji2djFMVPdd9
This brings the Chicago area tothreefour known installations:
N Sheridan Road @ W Bryn Mawr Ave (https://goo.gl/maps/8DEpRwMKMZ8tc3EK7) (option lane)
N Columbus Drive (NB) @ E Grand Ave (https://goo.gl/maps/Zn42Wji2djFMVPdd9) (former option lane, now two dedicated turns) (NEW)
N Columbus Drive (SB) @ E Illinois Street (https://goo.gl/maps/Zu7i8GP8ij2q6kKg9) (former option lane, now two dedicated turns) (NEW)
Thorndale Ave @ Park Blvd, Itasca (https://goo.gl/maps/SZSFA9SQdQVQ5JJM9) (true double left) (removed, now an off-ramp from the 390 Toll Road)
NB Sunset Ridge Road at Skokie Boulevard in Northbrook, IL (https://goo.gl/maps/y7wNqM5fJajUkXXT7) used to have one (left + left-thru-right)
Did Joliet Street at Cass Street in downtown Joliet get removed? (https://goo.gl/maps/LSegLmDAYmpL2kmJA) (left + left-thru)
Another two, that's great! I remember Brandon mentioning the one in Joliet way back when, but there was a bunch of confusion over whether it was split-phased or permissive, with the consensus being that it was permissive. If that street view image is to be believed, there's no question (and I'm sure, with you being familiar with the area, are already well aware of that). Since the image was from September of last year, I highly doubt it has been removed. I had simply forgotten about it (both it, and that Joliet was so close to Chicago).
Title: Re: Double left turns with permissive phasing
Post by: deathtopumpkins on March 03, 2020, 08:59:28 AM
Post by: deathtopumpkins on March 03, 2020, 08:59:28 AM
That one from Northbrook, IL reminded me of one I had forgotten about in Cambridge, MA, that I don't think has been mentioned:
https://goo.gl/maps/6nZKYFeKn2PTUmtm9
If it's not clear from the streetview imagery, the dual left from Cambridgeside Pl onto Land Blvd runs concurrently with the signal for the hotel driveway across Land Blvd.
Is this the first "pure" example (i.e. not LTOR) from Mass?
https://goo.gl/maps/6nZKYFeKn2PTUmtm9
If it's not clear from the streetview imagery, the dual left from Cambridgeside Pl onto Land Blvd runs concurrently with the signal for the hotel driveway across Land Blvd.
Is this the first "pure" example (i.e. not LTOR) from Mass?
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 03, 2020, 01:06:47 PM
Post by: jakeroot on March 03, 2020, 01:06:47 PM
Quote from: deathtopumpkins on March 03, 2020, 08:59:28 AM
That one from Northbrook, IL reminded me of one I had forgotten about in Cambridge, MA, that I don't think has been mentioned:
https://goo.gl/maps/6nZKYFeKn2PTUmtm9
If it's not clear from the streetview imagery, the dual left from Cambridgeside Pl onto Land Blvd runs concurrently with the signal for the hotel driveway across Land Blvd.
Is this the first "pure" example (i.e. not LTOR) from Mass?
Nice find. Judging by that imagery, not everyone is yielding properly!
I think it was mentioned that there was a temporary variation in either Springfield or Worcester (or somewhere else), but that it was removed. That would make this the only permanent one that I know of.
Title: Re: Double left turns with permissive phasing
Post by: deathtopumpkins on March 04, 2020, 09:43:22 AM
Post by: deathtopumpkins on March 04, 2020, 09:43:22 AM
And I realized yesterday that there's an almost identical setup downtown that hadn't occured to me either! So I guess it's not the only one.
https://goo.gl/maps/gxEd538jb4eEPbhF9
The dual left from North St to Congress St runs concurrently with the City Hall garage exit across the street.
https://goo.gl/maps/gxEd538jb4eEPbhF9
The dual left from North St to Congress St runs concurrently with the City Hall garage exit across the street.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 04, 2020, 06:32:41 PM
Post by: jakeroot on March 04, 2020, 06:32:41 PM
Quote from: deathtopumpkins on March 04, 2020, 09:43:22 AM
And I realized yesterday that there's an almost identical setup downtown that hadn't occured to me either! So I guess it's not the only one.
https://goo.gl/maps/gxEd538jb4eEPbhF9
The dual left from North St to Congress St runs concurrently with the City Hall garage exit across the street.
Bit awkward with the RHD setup leaving City Hall. Still would count, since left turns yield to everything else, no matter how awkward.
Title: Re: Double left turns with permissive phasing
Post by: Revive 755 on March 07, 2020, 11:07:18 PM
Post by: Revive 755 on March 07, 2020, 11:07:18 PM
Another one that may not have been previously mentioned for Chicagoland: SB IL 31 at Chicago Street near Downtown Elgin (left plus left-thru). (https://goo.gl/maps/CUP2ASjon5SB4i559)
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 08, 2020, 07:55:34 PM
Post by: jakeroot on March 08, 2020, 07:55:34 PM
Quote from: Revive 755 on March 07, 2020, 11:07:18 PM
Another one that may not have been previously mentioned for Chicagoland: SB IL 31 at Chicago Street near Downtown Elgin (left plus left-thru). (https://goo.gl/maps/CUP2ASjon5SB4i559)
That one even has a double 5-section tower, unlike the others from Chicago. Extra cool.
It would seem that Chicago is actually full of these things.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on March 10, 2020, 11:19:32 AM
Post by: mrsman on March 10, 2020, 11:19:32 AM
DC is going through a process of adjusting the signals on all double turns to avoid conflict with pedestrians. I don't believe there were any double lefts permissive against opposing traffic [which is the main emphasis of this thread], but there were double lefts and double rights against pedestrians that are now going to become protected only turns to separate turning traffic from pedestrians.
In the name of Vision Zero.
https://ddot.dc.gov/page/intersections-dual-turn-lanes
In the name of Vision Zero.
https://ddot.dc.gov/page/intersections-dual-turn-lanes
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 10, 2020, 08:02:54 PM
Post by: jakeroot on March 10, 2020, 08:02:54 PM
Quote from: mrsman on March 10, 2020, 11:19:32 AM
DC is going through a process of adjusting the signals on all double turns to avoid conflict with pedestrians. I don't believe there were any double lefts permissive against opposing traffic [which is the main emphasis of this thread], but there were double lefts and double rights against pedestrians that are now going to become protected only turns to separate turning traffic from pedestrians.
In the name of Vision Zero.
https://ddot.dc.gov/page/intersections-dual-turn-lanes
There are/were definitely a bunch. Quite a few of those mentioned in the "completed" column were against traffic.
Probably the busiest was westbound Independence at 12th St SW, which I captured a video of last year (note two lanes of traffic waiting to turn left at the beginning):
https://youtu.be/x5RbNLwuoqc
The intersection was definitely awkward given the sheer number of movements occurring simultaneously, plus the overlapping turns and the yellow trap for eastbound Independence traffic. Oh my!
My mother works just a couple blocks from the intersection, and I've walked through it many times before (especially given the metro stop right on that corner). For as busy as it is, I don't recall any collisions or even close calls. Everything moves fairly slow, and there's so many pedestrians that it's basically impossible to not notice them.
Oddly, none of the mentioned intersections are this one at Louisiana NW and New Jersey NW (https://goo.gl/maps/cgJKeU5RptMULypk6), a near-classic double permissive left (with an option lane). Guess this one stays.
From a layman's perspective, something I think would really help DC would be better channelization of lanes. Independence @ 12th St SW could easily be improved with offsetting the left turn lanes, and certainly some improved markings would help, but I guess it's just too expensive
Title: Re: Double left turns with permissive phasing
Post by: mrsman on March 11, 2020, 10:17:38 PM
Post by: mrsman on March 11, 2020, 10:17:38 PM
3rd/Independence seems to be one of the first examples of what is going on here.
Plus, it seems like the old and new configurations can be found on GSV.
Original configuration has a left turn lane and an option left/straight lane. Permissive lagging left (opposing lefts prohibited). Because of this, it isn't too dangerous to allow the permissive phasing. Opposing lefts prohibited, so the opposing lefts don't block the view. And most of teh time, it's busy enough that no turns are happening during the permissive phase anyway, but where opposing traffic is light, you won't block the straight traffic since you don't have to wait for the green arrow.
Now, to accommodate pedestrian safety, the option lane became a left turn lane and it is controlled by protected only lefts.
-------
As one considers this whole topic, there seem to be certain things that are common in these situations. Certain states like Arizona, Colorado, and Texas tend to be more permissive than others. More common in situations where opposing lefts are prohibited. More common where there are option lanes rather than full double lanes. Any other general observations, Jake?
Plus, it seems like the old and new configurations can be found on GSV.
Original configuration has a left turn lane and an option left/straight lane. Permissive lagging left (opposing lefts prohibited). Because of this, it isn't too dangerous to allow the permissive phasing. Opposing lefts prohibited, so the opposing lefts don't block the view. And most of teh time, it's busy enough that no turns are happening during the permissive phase anyway, but where opposing traffic is light, you won't block the straight traffic since you don't have to wait for the green arrow.
Now, to accommodate pedestrian safety, the option lane became a left turn lane and it is controlled by protected only lefts.
-------
As one considers this whole topic, there seem to be certain things that are common in these situations. Certain states like Arizona, Colorado, and Texas tend to be more permissive than others. More common in situations where opposing lefts are prohibited. More common where there are option lanes rather than full double lanes. Any other general observations, Jake?
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on March 18, 2020, 10:01:37 AM
Post by: fwydriver405 on March 18, 2020, 10:01:37 AM
Found this one in Nogales AZ near the southern terminus of Interstate 19. The one on Grand Ave is a definite yes, but not sure about the one on Crawford St where one of the approaches are right turn only:
Grand Ave to Crawford St/I-19 N (definite yes) (https://www.google.com/maps/@31.3343849,-110.941405,3a,36.7y,29.66h,88.94t/data=!3m6!1e1!3m4!1s5NGTDS3cpjJCjdz1VQd1HQ!2e0!7i13312!8i6656)
Crawford St (unsure about) (https://www.google.com/maps/@31.3346917,-110.9411623,3a,72.5y,291.21h,87.46t/data=!3m6!1e1!3m4!1skKYqqNLC5s2b8MT8uqyqfw!2e0!7i13312!8i6656)
Grand Ave to Crawford St/I-19 N (definite yes) (https://www.google.com/maps/@31.3343849,-110.941405,3a,36.7y,29.66h,88.94t/data=!3m6!1e1!3m4!1s5NGTDS3cpjJCjdz1VQd1HQ!2e0!7i13312!8i6656)
Crawford St (unsure about) (https://www.google.com/maps/@31.3346917,-110.9411623,3a,72.5y,291.21h,87.46t/data=!3m6!1e1!3m4!1skKYqqNLC5s2b8MT8uqyqfw!2e0!7i13312!8i6656)
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 19, 2020, 03:13:39 AM
Post by: jakeroot on March 19, 2020, 03:13:39 AM
Quote from: mrsman on March 11, 2020, 10:17:38 PM
As one considers this whole topic, there seem to be certain things that are common in these situations. Certain states like Arizona, Colorado, and Texas tend to be more permissive than others. More common in situations where opposing lefts are prohibited. More common where there are option lanes rather than full double lanes. Any other general observations, Jake?
Not a whole lot, beyond where they're most common.
Many of the Texas variants have surprised me with their negative-offset construction, like this one in Fort Worth (https://goo.gl/maps/mSPB7j2tyuCizxG88) that was disabled due to a high number of crashes. Colorado also has a surprising number without any consideration of oncoming visibility, but they don't (usually (https://goo.gl/maps/fHkwty9a6ofw6VWTA)) construct medians on the left (without any gap on the right, like Tucson) that make visibility worse than without any median. Unlike Texas, I've not heard of any being shut off in Colorado, so they must be better-trained at handling these (not surprising given the sheer number across Colorado ... probably the highest per-capita in the US).
Another observation might be that they are sometimes used without consideration at side-streets, where there is limited available green time to call for separate movements. Three examples of this have existed along Montlake Boulevard in Seattle: here (https://goo.gl/maps/n37trFv8uAysRPDh8) (with a severe path overlap) and here (https://goo.gl/maps/bNymyZ7U4hVsLY3c6); a third example (https://goo.gl/maps/8EHbgYmrcxc9Jd1q6) now operates with flashing yellow right arrows for oncoming traffic, as does another to the south at equally-busy Rainier Ave (https://goo.gl/maps/561wVykwT6Jsfyg98).
In a similar vein, they are more common when opposite a driveway; Pierce County, WA's only example (https://goo.gl/maps/xXacktSEinz7gNxq8) of a double-permissive left was this kind of setup (now split-phased); another example (https://goo.gl/maps/wCDGCmyt3uR2JSYu5) in Tucson like this. The one in Boston just up-thread is opposite a driveway leaving city hall as well.
Another minor observation would be Washington and Oregon's lack of interest in prohibiting double-left turns onto on-ramps during red periods. Neither DOT installs double-left turns with true permissive phasing (yield on green, or yield on FYA), but rarely (if ever) prohibit double left turns on red from two-way to one-way streets. This is not a true double-permissive left in the spirit of this thread, but it's an interesting observation. In practice, they don't work any different than Maryland's flashing red arrows (though stopping is absolutely required). Idaho and Michigan have similar laws, though the former does not allow turns against red arrows, and the latter already has several true permissive double left turns along state highways, unlike Washington and Oregon.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 19, 2020, 03:25:03 AM
Post by: jakeroot on March 19, 2020, 03:25:03 AM
Quote from: fwydriver405 on March 18, 2020, 10:01:37 AM
Found this one in Nogales AZ near the southern terminus of Interstate 19. The one on Grand Ave is a definite yes, but not sure about the one on Crawford St where one of the approaches are right turn only:
Grand Ave to Crawford St/I-19 N (definite yes) (https://www.google.com/maps/@31.3343849,-110.941405,3a,36.7y,29.66h,88.94t/data=!3m6!1e1!3m4!1s5NGTDS3cpjJCjdz1VQd1HQ!2e0!7i13312!8i6656)
Crawford St (unsure about) (https://www.google.com/maps/@31.3346917,-110.9411623,3a,72.5y,291.21h,87.46t/data=!3m6!1e1!3m4!1skKYqqNLC5s2b8MT8uqyqfw!2e0!7i13312!8i6656)
Looks to me like the latter also operates with permissive phasing. I believe that the green arrows should be green orbs, as green arrows are not to be used when other traffic that may conflict with that movement, has anything other than a red indication. This rule is ignored fairly often these days, with the normalisation of right-turn signals (particularly those with flashing yellow arrows), but I think the rule still remains.
Title: Re: Double left turns with permissive phasing
Post by: kphoger on March 27, 2020, 05:53:22 PM
Post by: kphoger on March 27, 2020, 05:53:22 PM
Quote from: jakeroot on August 23, 2019, 04:11:44 PMQuote from: kphoger on August 23, 2019, 03:10:35 PMQuote from: jakeroot on August 22, 2019, 01:26:17 AMQuote from: kphoger on August 21, 2019, 04:51:29 PM
The worst I've personally driven through is this example (https://goo.gl/maps/frSx7vuy4d99Q4HKA) in Coahuila. A single overhead signal for each direction of a four-lane divided federal highway with very heavy commercial traffic.
Yikes, that is bad. Looks to run split-phasing as well. Also not so good.
While split phasing is quite common in Mexico, I don't think this one does. I could be wrong, but I don't see any left turn arrows to make me think it does either.
I was basing it on these views:
https://goo.gl/maps/ME7bkpc2ZEvL1yFPA
https://goo.gl/maps/BMJgXEpGcc6ZgCTq5
Quote from: kphoger on August 23, 2019, 04:18:53 PM
Yeah, I noticed that too. I don't remember from personal experience, but I don't see how that would work without arrows.
Confirmed in person a week ago.
This stoplight runs split phasing with a single signal head in each direction and no arrows. Even though left turns are therefore protected, you'd never know it by looking at the signal.
AADT here was 14,330 last year, with 23% buses and trucks.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 28, 2020, 04:16:16 AM
Post by: jakeroot on March 28, 2020, 04:16:16 AM
Quote from: kphoger on March 27, 2020, 05:53:22 PM
Confirmed in person a week ago.
This stoplight runs split phasing with a single signal head in each direction and no arrows. Even though left turns are therefore protected, you'd never know it by looking at the signal.
AADT here was 14,330 last year, with 23% buses and trucks.
Really appreciate the update! Seems like Mexico is seriously lacking in proper signalisation outside of certain areas (Northern Mexico seems to be in worse shape).
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 28, 2020, 04:27:40 AM
Post by: jakeroot on March 28, 2020, 04:27:40 AM
Quote from: jakeroot on February 24, 2020, 03:13:05 PM
Found another in Chicago: https://goo.gl/maps/Zn42Wji2djFMVPdd9
This brings the Chicago area tothreefour known installations:
N Sheridan Road @ W Bryn Mawr Ave (https://goo.gl/maps/8DEpRwMKMZ8tc3EK7) (option lane)
N Columbus Drive (NB) @ E Grand Ave (https://goo.gl/maps/Zn42Wji2djFMVPdd9) (former option lane, now two dedicated turns)(NEW)
N Columbus Drive (SB) @ E Illinois Street (https://goo.gl/maps/Zu7i8GP8ij2q6kKg9) (former option lane, now two dedicated turns)(NEW)
Thorndale Ave @ Park Blvd, Itasca (https://goo.gl/maps/SZSFA9SQdQVQ5JJM9) (true double left) (removed, now an off-ramp from the 390 Toll Road)
Found more in Chicago. Both seem to be a fairly central area, so I'm definitely surprised someone hasn't mentioned either:
E Jackson Drive (WB) @ S Columbus Drive (https://goo.gl/maps/nY11a5j7tpGHMycU7) (option lane) (NEW)
E Monroe Street (EB) @ LSD (https://goo.gl/maps/y8LPBSbbDavLT6659) (two dedicated turn lanes) (NEW) (no protected phase)
Chicago has quickly become #1 among largest US cities! Of the ten largest cities, those in Texas might have some onto frontage roads, but these are so damn common I don't feel like including them on this list. Really not until you get towards Seattle or Denver, do you get cities with at least a couple of known installations (Denver having quite a few, Seattle having less than in the past). Eventually, down at #34, is Tucson, which is still reigning champ AFAIK.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on March 30, 2020, 12:50:08 AM
Post by: mrsman on March 30, 2020, 12:50:08 AM
Quote from: jakeroot on March 28, 2020, 04:27:40 AMQuote from: jakeroot on February 24, 2020, 03:13:05 PM
Found another in Chicago: https://goo.gl/maps/Zn42Wji2djFMVPdd9
This brings the Chicago area tothreefour known installations:
N Sheridan Road @ W Bryn Mawr Ave (https://goo.gl/maps/8DEpRwMKMZ8tc3EK7) (option lane)
N Columbus Drive (NB) @ E Grand Ave (https://goo.gl/maps/Zn42Wji2djFMVPdd9) (former option lane, now two dedicated turns)(NEW)
N Columbus Drive (SB) @ E Illinois Street (https://goo.gl/maps/Zu7i8GP8ij2q6kKg9) (former option lane, now two dedicated turns)(NEW)
Thorndale Ave @ Park Blvd, Itasca (https://goo.gl/maps/SZSFA9SQdQVQ5JJM9) (true double left) (removed, now an off-ramp from the 390 Toll Road)
Found more in Chicago. Both seem to be a fairly central area, so I'm definitely surprised someone hasn't mentioned either:
E Jackson Drive (WB) @ S Columbus Drive (https://goo.gl/maps/nY11a5j7tpGHMycU7) (option lane) (NEW)
E Monroe Street (EB) @ LSD (https://goo.gl/maps/y8LPBSbbDavLT6659) (two dedicated turn lanes) (NEW) (no protected phase)
Chicago has quickly become #1 among largest US cities! Of the ten largest cities, those in Texas might have some onto frontage roads, but these are so damn common I don't feel like including them on this list. Really not until you get towards Seattle or Denver, do you get cities with at least a couple of known installations (Denver having quite a few, Seattle having less than in the past). Eventually, down at #34, is Tucson, which is still reigning champ AFAIK.
Monroe/LSD is against a driveway from a Yacht Club. while still a double permissive turn, given that it is a private driveway, it is unlikely to get too much traffic.
I.e. aside from a small amount of driveway traffic, this is essentially a T-intersection.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 30, 2020, 02:22:14 AM
Post by: jakeroot on March 30, 2020, 02:22:14 AM
Quote from: mrsman on March 30, 2020, 12:50:08 AM
Monroe/LSD is against a driveway from a Yacht Club. while still a double permissive turn, given that it is a private driveway, it is unlikely to get too much traffic.
I.e. aside from a small amount of driveway traffic, this is essentially a T-intersection.
Indeed, not a ton of oncoming traffic (certainly the reason why there is no protected phase). But there is a lot of pedestrian traffic, and there does appear to be at least a few major attractions along that driveway, so I would still include it in this thread. It seems like it would be busy enough during tourist season (whenever this is, in Chicago).
As far as double left turns across driveways, I'm not against including them. I would absolutely include them, but I think each has to be considered on its individual merits: does it seem to get a lot of traffic? Does the driveway serve several businesses? Etc, etc. If it's just a regular turn across a single driveway from a home? Boring. But a double left turn across a private drive that has several active businesses and a lot of foot traffic to boot? That's pretty damn interesting.
More to the point, would the left turn receive split phasing or regular protected phasing in most municipalities? If the answer is "yes", it's worthy of this thread IMO.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on March 31, 2020, 07:00:15 PM
Post by: mrsman on March 31, 2020, 07:00:15 PM
Quote from: jakeroot on March 30, 2020, 02:22:14 AMQuote from: mrsman on March 30, 2020, 12:50:08 AM
Monroe/LSD is against a driveway from a Yacht Club. while still a double permissive turn, given that it is a private driveway, it is unlikely to get too much traffic.
I.e. aside from a small amount of driveway traffic, this is essentially a T-intersection.
Indeed, not a ton of oncoming traffic (certainly the reason why there is no protected phase). But there is a lot of pedestrian traffic, and there does appear to be at least a few major attractions along that driveway, so I would still include it in this thread. It seems like it would be busy enough during tourist season (whenever this is, in Chicago).
As far as double left turns across driveways, I'm not against including them. I would absolutely include them, but I think each has to be considered on its individual merits: does it seem to get a lot of traffic? Does the driveway serve several businesses? Etc, etc. If it's just a regular turn across a single driveway from a home? Boring. But a double left turn across a private drive that has several active businesses and a lot of foot traffic to boot? That's pretty damn interesting.
More to the point, would the left turn receive split phasing or regular protected phasing in most municipalities? If the answer is "yes", it's worthy of this thread IMO.
Sure, it merits inclusion because it is still yielding to opposing traffic. It just should be noted that since it is practically at the end of the road (only a few feet from Lake Michigan), the nature of traffic coming out of the driveway is not huge. Although, yes, technically more than at a private driveway.
Chicago is sort of interesting in this degree. Yes, it should be celebrated that there are quite a number of intersections with permissive double lefts. But it has other issues that I strongly disagree with. It seems to have many intersections with 5 aspect signals that are left on green arrow only, when that type of signal is almost universally used for PPLTs. Yes there is signage to that effect, but it still defies the general expectation.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 01, 2020, 02:26:11 AM
Post by: jakeroot on April 01, 2020, 02:26:11 AM
Quote from: mrsman on March 31, 2020, 07:00:15 PMQuote from: jakeroot on March 30, 2020, 02:22:14 AMQuote from: mrsman on March 30, 2020, 12:50:08 AM
Monroe/LSD is against a driveway from a Yacht Club. while still a double permissive turn, given that it is a private driveway, it is unlikely to get too much traffic.
I.e. aside from a small amount of driveway traffic, this is essentially a T-intersection.
Indeed, not a ton of oncoming traffic (certainly the reason why there is no protected phase). But there is a lot of pedestrian traffic, and there does appear to be at least a few major attractions along that driveway, so I would still include it in this thread. It seems like it would be busy enough during tourist season (whenever this is, in Chicago).
As far as double left turns across driveways, I'm not against including them. I would absolutely include them, but I think each has to be considered on its individual merits: does it seem to get a lot of traffic? Does the driveway serve several businesses? Etc, etc. If it's just a regular turn across a single driveway from a home? Boring. But a double left turn across a private drive that has several active businesses and a lot of foot traffic to boot? That's pretty damn interesting.
More to the point, would the left turn receive split phasing or regular protected phasing in most municipalities? If the answer is "yes", it's worthy of this thread IMO.
Sure, it merits inclusion because it is still yielding to opposing traffic. It just should be noted that since it is practically at the end of the road (only a few feet from Lake Michigan), the nature of traffic coming out of the driveway is not huge. Although, yes, technically more than at a private driveway.
Chicago is sort of interesting in this degree. Yes, it should be celebrated that there are quite a number of intersections with permissive double lefts. But it has other issues that I strongly disagree with. It seems to have many intersections with 5 aspect signals that are left on green arrow only, when that type of signal is almost universally used for PPLTs. Yes there is signage to that effect, but it still defies the general expectation.
Indeed. On many fronts, Illinois leads the midwest (hell, the country) in their signalization efforts, with many intersections resembling California-style placement (https://goo.gl/maps/rDQLzyRtLkQb1kaH7) but with many single-lane left turns using permissive phasing (unlike most of California), and apparently quite a few double lefts using it as well. But then yes, in Chicago, you have those ridiculous "on green arrow only" signs along several major arterials. I can only assume they were installed to satisfy the Chicago DOT's requirements for X-number of through signal heads, a difficult task for those arterials where protected phasing is desired but where overhead signals are not used. But that's a fairly poor excuse with advances in signal technology and placement strategies, and things should have been fixed a while ago.
I have wondered, given the Illinois tendency to push as far forward into the intersection as possible when turning (my method, but standard Illinois practice too), if some of the "on green arrow only" signs were removed, such as the one at Monroe/LSD, if drivers would instinctively start to turn with the green ball? Or even they'd get on autopilot and wait for the green arrow anyway. Based on what I know about "FIBs", I'm surprised they're obeyed at all.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on April 01, 2020, 08:41:03 AM
Post by: Amtrakprod on April 01, 2020, 08:41:03 AM
Quote from: jakeroot on April 01, 2020, 02:26:11 AMI would agree. If i had to rank traffic lights in the USA, Illinois is first place easily.Quote from: mrsman on March 31, 2020, 07:00:15 PMQuote from: jakeroot on March 30, 2020, 02:22:14 AMQuote from: mrsman on March 30, 2020, 12:50:08 AM
Monroe/LSD is against a driveway from a Yacht Club. while still a double permissive turn, given that it is a private driveway, it is unlikely to get too much traffic.
I.e. aside from a small amount of driveway traffic, this is essentially a T-intersection.
Indeed, not a ton of oncoming traffic (certainly the reason why there is no protected phase). But there is a lot of pedestrian traffic, and there does appear to be at least a few major attractions along that driveway, so I would still include it in this thread. It seems like it would be busy enough during tourist season (whenever this is, in Chicago).
As far as double left turns across driveways, I'm not against including them. I would absolutely include them, but I think each has to be considered on its individual merits: does it seem to get a lot of traffic? Does the driveway serve several businesses? Etc, etc. If it's just a regular turn across a single driveway from a home? Boring. But a double left turn across a private drive that has several active businesses and a lot of foot traffic to boot? That's pretty damn interesting.
More to the point, would the left turn receive split phasing or regular protected phasing in most municipalities? If the answer is "yes", it's worthy of this thread IMO.
Sure, it merits inclusion because it is still yielding to opposing traffic. It just should be noted that since it is practically at the end of the road (only a few feet from Lake Michigan), the nature of traffic coming out of the driveway is not huge. Although, yes, technically more than at a private driveway.
Chicago is sort of interesting in this degree. Yes, it should be celebrated that there are quite a number of intersections with permissive double lefts. But it has other issues that I strongly disagree with. It seems to have many intersections with 5 aspect signals that are left on green arrow only, when that type of signal is almost universally used for PPLTs. Yes there is signage to that effect, but it still defies the general expectation.
Indeed. On many fronts, Illinois leads the midwest (hell, the country) in their signalization efforts, with many intersections resembling California-style placement (https://goo.gl/maps/rDQLzyRtLkQb1kaH7) but with many single-lane left turns using permissive phasing (unlike most of California), and apparently quite a few double lefts using it as well. But then yes, in Chicago, you have those ridiculous "on green arrow only" signs along several major arterials. I can only assume they were installed to satisfy the Chicago DOT's requirements for X-number of through signal heads, a difficult task for those arterials where protected phasing is desired but where overhead signals are not used. But that's a fairly poor excuse with advances in signal technology and placement strategies, and things should have been fixed a while ago.
I have wondered, given the Illinois tendency to push as far forward into the intersection as possible when turning (my method, but standard Illinois practice too), if some of the "on green arrow only" signs were removed, such as the one at Monroe/LSD, if drivers would instinctively start to turn with the green ball? Or even they'd get on autopilot and wait for the green arrow anyway. Based on what I know about "FIBs", I'm surprised they're obeyed at all.
iPhone
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 01, 2020, 03:13:12 PM
Post by: jakeroot on April 01, 2020, 03:13:12 PM
Quote from: Amtrakprod on April 01, 2020, 08:41:03 AM
I would agree. If i had to rank traffic lights in the USA, Illinois is first place easily.
I might still put California first, but only because of their consistency. Illinois has some terrible inconsistencies. Springfield has more consistent (and thorough) placement strategies than Bloomington, for example (who uses only basic Illinois requirements: two signals for every movement). Apparently near-side signals are not an absolutely requirement in Illinois. It just so happens that Chicago and surrounding municipalities (including ISTHA) have really good strategies.
Title: Re: Double left turns with permissive phasing
Post by: deathtopumpkins on April 02, 2020, 09:25:57 AM
Post by: deathtopumpkins on April 02, 2020, 09:25:57 AM
IMHO California has way too many protected lefts to ever rank first.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on April 02, 2020, 01:15:18 PM
Post by: mrsman on April 02, 2020, 01:15:18 PM
Quote from: deathtopumpkins on April 02, 2020, 09:25:57 AM
IMHO California has way too many protected lefts to ever rank first.
Correct, only first in signal placement. Near dead last in signal operation.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on April 02, 2020, 02:29:32 PM
Post by: fwydriver405 on April 02, 2020, 02:29:32 PM
Quote from: mrsman on April 02, 2020, 01:15:18 PMQuote from: deathtopumpkins on April 02, 2020, 09:25:57 AM
IMHO California has way too many protected lefts to ever rank first.
Correct, only first in signal placement. Near dead last in signal operation.
Found this one in Downtown San Francisco (option lane) (https://www.google.com/maps/@37.7782294,-122.4009307,3a,35.3y,115.59h,82.61t/data=!3m6!1e1!3m4!1sJwO5v6S2_xSde0klRgGg_A!2e0!7i16384!8i8192). The left lane can choose between I-80 E or Bryant St, and the middle to Bryant St or continue straight to 5th St. Many drivers I've seen during rush hour, use the middle lane to turn onto I-80 E...
I believe there's another one somewhere in SF but not sure where.
EDIT: A few more -
Van Ness and Broadway (albeit temporary? - 2 left turn lanes converted from left + option) (https://www.google.com/maps/@37.7959908,-122.4235818,3a,26.4y,155.38h,91.91t/data=!3m6!1e1!3m4!1sTZ85n9eIsaQ_vM7CFlG_mw!2e0!7i16384!8i8192)
Sloat Blvd and 19th Ave (https://www.google.com/maps/@37.7345949,-122.4755383,3a,38y,89h,87.54t/data=!3m6!1e1!3m4!1sNR9Or460omA2ZMGojtK6tw!2e0!7i16384!8i8192) (left + option)
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 02, 2020, 04:20:03 PM
Post by: jakeroot on April 02, 2020, 04:20:03 PM
^^
Holy s***! I didn't think California had any of these (left from earlier years or otherwise). Awesome finds, fwydriver!
Literally the only two I've ever found in California, beyond any that may have existed at one-way streets in downtown LA back before the 2000s, were these two:
* Cupertino, outside of the new Apple Park during construction (https://goo.gl/maps/itapjjmFxLmgn6ZDA)
* San Jose, exit from the Aligent Technologies Campus (https://goo.gl/maps/3Fi9Wo3L14gwwHQ99)
To actually see not just one or two, but three proper double left turns along major city streets with signals is really cool, and not something I thought existed in California (at least not anymore...I do recognize that these appear to be old installations). The latter two (at Broadway, and at 19th Ave) are particularly cool because they aren't on to one-way streets, although there is no oncoming left turn.
EDIT: The one at Sloat/19th is also cool just because of how big the intersection is. Anywhere else in California, I suspect this would either be split-phased (as wasteful as that would be given the lack of an oncoming left), or the double left turns restriped without an option lane, and a protected-only signal put in place.
Holy s***! I didn't think California had any of these (left from earlier years or otherwise). Awesome finds, fwydriver!
Literally the only two I've ever found in California, beyond any that may have existed at one-way streets in downtown LA back before the 2000s, were these two:
* Cupertino, outside of the new Apple Park during construction (https://goo.gl/maps/itapjjmFxLmgn6ZDA)
* San Jose, exit from the Aligent Technologies Campus (https://goo.gl/maps/3Fi9Wo3L14gwwHQ99)
To actually see not just one or two, but three proper double left turns along major city streets with signals is really cool, and not something I thought existed in California (at least not anymore...I do recognize that these appear to be old installations). The latter two (at Broadway, and at 19th Ave) are particularly cool because they aren't on to one-way streets, although there is no oncoming left turn.
EDIT: The one at Sloat/19th is also cool just because of how big the intersection is. Anywhere else in California, I suspect this would either be split-phased (as wasteful as that would be given the lack of an oncoming left), or the double left turns restriped without an option lane, and a protected-only signal put in place.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on April 03, 2020, 10:18:15 AM
Post by: mrsman on April 03, 2020, 10:18:15 AM
Quote from: fwydriver405 on April 02, 2020, 02:29:32 PMQuote from: mrsman on April 02, 2020, 01:15:18 PMQuote from: deathtopumpkins on April 02, 2020, 09:25:57 AM
IMHO California has way too many protected lefts to ever rank first.
Correct, only first in signal placement. Near dead last in signal operation.
Found this one in Downtown San Francisco (option lane) (https://www.google.com/maps/@37.7782294,-122.4009307,3a,35.3y,115.59h,82.61t/data=!3m6!1e1!3m4!1sJwO5v6S2_xSde0klRgGg_A!2e0!7i16384!8i8192). The left lane can choose between I-80 E or Bryant St, and the middle to Bryant St or continue straight to 5th St. Many drivers I've seen during rush hour, use the middle lane to turn onto I-80 E...
I believe there's another one somewhere in SF but not sure where.
EDIT: A few more -
Van Ness and Broadway (albeit temporary? - 2 left turn lanes converted from left + option) (https://www.google.com/maps/@37.7959908,-122.4235818,3a,26.4y,155.38h,91.91t/data=!3m6!1e1!3m4!1sTZ85n9eIsaQ_vM7CFlG_mw!2e0!7i16384!8i8192)
Sloat Blvd and 19th Ave (https://www.google.com/maps/@37.7345949,-122.4755383,3a,38y,89h,87.54t/data=!3m6!1e1!3m4!1sNR9Or460omA2ZMGojtK6tw!2e0!7i16384!8i8192) (left + option)
Probably given the traffic demand, both lanes SHOULD be allowed to turn left onto the freeway.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on April 03, 2020, 11:36:20 AM
Post by: mrsman on April 03, 2020, 11:36:20 AM
While good to see more of these, it is understandable to see the sf configurations. No opposing left. Lagging left. Option lane. Clear sightlines.
On very busy streets with option lanes, this signalization is ideal. You may be ALLOWED to turn left during permissive phase, but practically speaking, you will only be ABLE to during the protected phase, during most parts of the day. The typical concerns that normally disallow permissive double left don't really apply here. And it's nice that the DOT recognizes it and allows for the possibility of permissive left and avoids split phasing.
Nexus 5X
On very busy streets with option lanes, this signalization is ideal. You may be ALLOWED to turn left during permissive phase, but practically speaking, you will only be ABLE to during the protected phase, during most parts of the day. The typical concerns that normally disallow permissive double left don't really apply here. And it's nice that the DOT recognizes it and allows for the possibility of permissive left and avoids split phasing.
Nexus 5X
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 03, 2020, 01:14:00 PM
Post by: jakeroot on April 03, 2020, 01:14:00 PM
Quote from: mrsman on April 03, 2020, 10:18:15 AMQuote from: fwydriver405 on April 02, 2020, 02:29:32 PM
Found this one in Downtown San Francisco (option lane) (https://www.google.com/maps/@37.7782294,-122.4009307,3a,35.3y,115.59h,82.61t/data=!3m6!1e1!3m4!1sJwO5v6S2_xSde0klRgGg_A!2e0!7i16384!8i8192). The left lane can choose between I-80 E or Bryant St, and the middle to Bryant St or continue straight to 5th St. Many drivers I've seen during rush hour, use the middle lane to turn onto I-80 E...
Probably given the traffic demand, both lanes SHOULD be allowed to turn left onto the freeway.
I agree. There are three lanes on that on-ramp. No reason they couldn't allow a sharp double left turn.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 03, 2020, 04:30:22 PM
Post by: jakeroot on April 03, 2020, 04:30:22 PM
Quote from: mrsman on April 03, 2020, 11:36:20 AM
While good to see more of these, it is understandable to see the sf configurations. No opposing left. Lagging left. Option lane. Clear sightlines.
On very busy streets with option lanes, this signalization is ideal. You may be ALLOWED to turn left during permissive phase, but practically speaking, you will only be ABLE to during the protected phase, during most parts of the day. The typical concerns that normally disallow permissive double left don't really apply here. And it's nice that the DOT recognizes it and allows for the possibility of permissive left and avoids split phasing.
Again, I agree with your points. Nevertheless, it surprises me that SF installed these to begin with. I never associated California with permissive left turns along major arterials (outside of LA proper), much less any that allow left turns from two lanes. I think most Californian municipalities, and even San Francisco themselves along any reconstructed arterials, would design the road layout in a manner appropriate for protected-only left turns if the road were designed today. Which is more than unfortunate IMO, since these seem to work adequately when properly designed.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on April 03, 2020, 07:07:53 PM
Post by: fwydriver405 on April 03, 2020, 07:07:53 PM
Quote from: jakeroot on April 03, 2020, 04:30:22 PMQuote from: mrsman on April 03, 2020, 11:36:20 AM
While good to see more of these, it is understandable to see the sf configurations. No opposing left. Lagging left. Option lane. Clear sightlines.
On very busy streets with option lanes, this signalization is ideal. You may be ALLOWED to turn left during permissive phase, but practically speaking, you will only be ABLE to during the protected phase, during most parts of the day. The typical concerns that normally disallow permissive double left don't really apply here. And it's nice that the DOT recognizes it and allows for the possibility of permissive left and avoids split phasing.
Again, I agree with your points. Nevertheless, it surprises me that SF installed these to begin with. I never associated California with permissive left turns along major arterials (outside of LA proper), much less any that allow left turns from two lanes. I think most Californian municipalities, and even San Francisco themselves along any reconstructed arterials, would design the road layout in a manner appropriate for protected-only left turns if the road were designed today. Which is more than unfortunate IMO, since these seem to work adequately when properly designed.
I believe Van Ness Ave (https://www.sfmta.com/project-updates/how-get-around-without-turning-left-van-ness) is being reconstructed in that area to remove left turns in that area and to add bus lanes in the middle of the road. The only left turns that are being retained are:
SB Van Ness onto EB Broadway (the example I posted)
NB Van Ness onto WB Lombard (triple left turn lane, protected only)
I wonder what will happen with the SB Van Ness onto EB Broadway double left when the entire project is complete... especially with the new bus lanes.
Also, at least one SF intersection was converted from PPLT double left + thru to protected only recently. Harrison to I-80 E's (current (https://www.google.com/maps/@37.7862294,-122.3927,3a,18y,236.57h,93.99t/data=!3m7!1e1!3m5!1sMnz8Kah0kxmLePtwMViAxQ!2e0!6s%2F%2Fgeo0.ggpht.com%2Fcbk%3Fpanoid%3DMnz8Kah0kxmLePtwMViAxQ%26output%3Dthumbnail%26cb_client%3Dsearch.revgeo_and_fetch.gps%26thumb%3D2%26w%3D96%26h%3D64%26yaw%3D240.5388%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192)) middle lane was converted from thru-left (https://www.google.com/maps/@37.7862696,-122.3926549,3a,75y,238.26h,96t/data=!3m7!1e1!3m5!1spMda-UFLSc0TVjqzQDFuhg!2e0!5s20110401T000000!7i13312!8i6656) to a dedicated only left turn lane in 2013. Of course, they had to change the phasing from PPLT lag left to protected only. Still lagging left though... (https://youtu.be/4OWi4VVqm64?t=30)(pay attention to the arrow in the distant signal)
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 04, 2020, 12:40:26 AM
Post by: jakeroot on April 04, 2020, 12:40:26 AM
Quote from: fwydriver405 on April 03, 2020, 07:07:53 PM
Also, at least one SF intersection was converted from PPLT double left + thru to protected only recently. Harrison to I-80 E's (current (https://www.google.com/maps/@37.7862294,-122.3927,3a,18y,236.57h,93.99t/data=!3m7!1e1!3m5!1sMnz8Kah0kxmLePtwMViAxQ!2e0!6s%2F%2Fgeo0.ggpht.com%2Fcbk%3Fpanoid%3DMnz8Kah0kxmLePtwMViAxQ%26output%3Dthumbnail%26cb_client%3Dsearch.revgeo_and_fetch.gps%26thumb%3D2%26w%3D96%26h%3D64%26yaw%3D240.5388%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192)) middle lane was converted from thru-left (https://www.google.com/maps/@37.7862696,-122.3926549,3a,75y,238.26h,96t/data=!3m7!1e1!3m5!1spMda-UFLSc0TVjqzQDFuhg!2e0!5s20110401T000000!7i13312!8i6656) to a dedicated only left turn lane in 2013. Of course, they had to change the phasing from PPLT lag left to protected only. Still lagging left though... (https://youtu.be/4OWi4VVqm64?t=30)(pay attention to the arrow in the distant signal)
So there was even more? Very interesting. Did you live in the area? Curious because that KRON4 video was from soon after the signal was modified, and the story seems to about the massive tailbacks being caused by that left turn. I would be interested in knowing how that signal modification has affected traffic flow. Usually the main arguments against these are either too many crashes, or pedestrian conflicts. But there doesn't seem to be that much oncoming traffic (total non-scientific observation), and there is no pedestrian crossing. So why the change? hmm.
Quote from: fwydriver405 on April 03, 2020, 07:07:53 PM
I believe Van Ness Ave (https://www.sfmta.com/project-updates/how-get-around-without-turning-left-van-ness) is being reconstructed in that area to remove left turns in that area and to add bus lanes in the middle of the road. The only left turns that are being retained are:
SB Van Ness onto EB Broadway (the example I posted)
NB Van Ness onto WB Lombard (triple left turn lane, protected only)
I wonder what will happen with the SB Van Ness onto EB Broadway double left when the entire project is complete... especially with the new bus lanes.
Typically with center bus lanes, any permissive left turns are eliminated, as traffic would have to yield to buses from behind them, oncoming buses, oncoming traffic, and pedestrians. Even I think this might be too much! South Africa, a haven for permissive right turns (they drive on the left), does not allow them across bus lanes, except where the buses do not have constant green lights (such as when they have to make turns (https://goo.gl/maps/GWenWH7WENeJADd58)).
The catch will be if the BRT lanes merge with general traffic near those left turns. If that happens, the left turns can probably stay, as the primary reason for eliminating permissive turns across bus lanes is due to buses coming from behind you. Barring that, there's no reason the double left onto Broadway would need to lose its permissive phase. At exceptionally busy turns, South Africa will merge buses with traffic, but the buses get a "pre-signal" (https://goo.gl/maps/1YNWmPVQC8mobjKt6) that allows them to merge into the through lanes prior to the beginning of the turn lane. I've not seen this used elsewhere, but seems like an option for Van Ness @ Broadway and Lombard.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on April 05, 2020, 04:59:59 PM
Post by: mrsman on April 05, 2020, 04:59:59 PM
Quote from: fwydriver405 on April 03, 2020, 07:07:53 PMQuote from: jakeroot on April 03, 2020, 04:30:22 PMQuote from: mrsman on April 03, 2020, 11:36:20 AM
While good to see more of these, it is understandable to see the sf configurations. No opposing left. Lagging left. Option lane. Clear sightlines.
On very busy streets with option lanes, this signalization is ideal. You may be ALLOWED to turn left during permissive phase, but practically speaking, you will only be ABLE to during the protected phase, during most parts of the day. The typical concerns that normally disallow permissive double left don't really apply here. And it's nice that the DOT recognizes it and allows for the possibility of permissive left and avoids split phasing.
Again, I agree with your points. Nevertheless, it surprises me that SF installed these to begin with. I never associated California with permissive left turns along major arterials (outside of LA proper), much less any that allow left turns from two lanes. I think most Californian municipalities, and even San Francisco themselves along any reconstructed arterials, would design the road layout in a manner appropriate for protected-only left turns if the road were designed today. Which is more than unfortunate IMO, since these seem to work adequately when properly designed.
I believe Van Ness Ave (https://www.sfmta.com/project-updates/how-get-around-without-turning-left-van-ness) is being reconstructed in that area to remove left turns in that area and to add bus lanes in the middle of the road. The only left turns that are being retained are:
SB Van Ness onto EB Broadway (the example I posted)
NB Van Ness onto WB Lombard (triple left turn lane, protected only)
I wonder what will happen with the SB Van Ness onto EB Broadway double left when the entire project is complete... especially with the new bus lanes.
Also, at least one SF intersection was converted from PPLT double left + thru to protected only recently. Harrison to I-80 E's (current (https://www.google.com/maps/@37.7862294,-122.3927,3a,18y,236.57h,93.99t/data=!3m7!1e1!3m5!1sMnz8Kah0kxmLePtwMViAxQ!2e0!6s%2F%2Fgeo0.ggpht.com%2Fcbk%3Fpanoid%3DMnz8Kah0kxmLePtwMViAxQ%26output%3Dthumbnail%26cb_client%3Dsearch.revgeo_and_fetch.gps%26thumb%3D2%26w%3D96%26h%3D64%26yaw%3D240.5388%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192)) middle lane was converted from thru-left (https://www.google.com/maps/@37.7862696,-122.3926549,3a,75y,238.26h,96t/data=!3m7!1e1!3m5!1spMda-UFLSc0TVjqzQDFuhg!2e0!5s20110401T000000!7i13312!8i6656) to a dedicated only left turn lane in 2013. Of course, they had to change the phasing from PPLT lag left to protected only. Still lagging left though... (https://youtu.be/4OWi4VVqm64?t=30)(pay attention to the arrow in the distant signal)
San Francisco is pretty well known for having many major 2-way corridors that completely disallow nearly all left turns altogether: 19th Ave, Sunset, Geary. In pre-construction days there were several intersections where lefts were prohibited from Van Ness, but it's true that more were allowed than just Lombard and Broadway. Lombard-Van Ness - Broadway is a main connecting route from the Golden Gate Bridge to Downtown SF, which is why there are multiple left turn lanes and why the lefts are still allowed even with the construction (and will probably still be allowed after the bus lanes are put in place).
I think that the bus lane would probably end at Greenwhich (one block south of Lombard). They need some way to allow for that massive left turn, and there would be no additional room for a bus lane. At Broadway, there will probably be a protected-only left (to be made from the lane that is to the right of the bus lane), but it may be limited to one lane.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on April 05, 2020, 07:03:37 PM
Post by: fwydriver405 on April 05, 2020, 07:03:37 PM
Quote from: jakeroot on April 04, 2020, 12:40:26 AM
So there was even more? Very interesting. Did you live in the area? Curious because that KRON4 video was from soon after the signal was modified, and the story seems to about the massive tailbacks being caused by that left turn. I would be interested in knowing how that signal modification has affected traffic flow. Usually the main arguments against these are either too many crashes, or pedestrian conflicts. But there doesn't seem to be that much oncoming traffic (total non-scientific observation), and there is no pedestrian crossing. So why the change? hmm.
I observed those double left turns when I was on holiday to Downtown San Francisco in 2013 and 2015 and passed thru Harrison and 1st Ave to get on to the Bay Bridge, as well as passing thru Van Ness Ave and Broadway on our way to the Golden Gate Bridge. The rest of the intersections were observed during Stanley Robert's former "People Behaving Badly" series when he used to work at KRON4.
Quote from: mrsman on April 05, 2020, 04:59:59 PM
I think that the bus lane would probably end at Greenwhich (one block south of Lombard). They need some way to allow for that massive left turn, and there would be no additional room for a bus lane. At Broadway, there will probably be a protected-only left (to be made from the lane that is to the right of the bus lane), but it may be limited to one lane.
Does Downtown SF use flashing yellow arrow signals for permissive turns at all?
Not to be confused with the flashing yellow balls that SF uses at some intersections:
Height and Octavia (https://www.google.com/maps/@37.7729067,-122.4240451,3a,21.3y,78.07h,89.82t/data=!3m7!1e1!3m5!1seKV6OJhQTef6_st96jXMIw!2e0!5s20170801T000000!7i13312!8i6656) (which should really an all-arrow FYA on EB Haight)
Fremont and Harrison (https://www.google.com/maps/@37.7867673,-122.3922255,3a,75y,117.16h,84.74t/data=!3m6!1e1!3m4!1sbfp70WsqzlSxX-Dg3FCNLQ!2e0!7i13312!8i6656) (again, should really be all-arrow signals, red ball for the right turn)
Title: Re: Double left turns with permissive phasing
Post by: mrsman on April 06, 2020, 08:26:25 AM
Post by: mrsman on April 06, 2020, 08:26:25 AM
Quote from: fwydriver405 on April 05, 2020, 07:03:37 PM
Does Downtown SF use flashing yellow arrow signals for permissive turns at all?
I'm not aware of any, but they are allowed in CA, so there should be no problem with them.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on April 10, 2020, 08:04:41 PM
Post by: Amtrakprod on April 10, 2020, 08:04:41 PM
Lincoln NE, https://www.google.com/maps/@40.815802,-96.7083362,3a,30.1y,272.94h,93.67t/data=!3m6!1e1!3m4!1sJhHfcrOHNhFN11UqYIWagA!2e0!7i16384!8i8192
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 10, 2020, 09:16:24 PM
Post by: jakeroot on April 10, 2020, 09:16:24 PM
Quote from: Amtrakprod on April 10, 2020, 08:04:41 PM
Lincoln NE, https://www.google.com/maps/@40.815802,-96.7083362,3a,30.1y,272.94h,93.67t/data=!3m6!1e1!3m4!1sJhHfcrOHNhFN11UqYIWagA!2e0!7i16384!8i8192
That's a very interesting example. There is technically no oncoming traffic that would proceed directly past the yielding traffic, but traffic does still need to yield to oncoming drivers (turning right into their destined lanes), as well as pedestrians. In that sense, it kind of hits the spirit of this thread. There are flashing yellow arrows for both approaches, which is fairly unusual for this kind of downtown intersection, but the oncoming traffic also has a flashing yellow arrow. I'm very interested to see what the "failure to yield" rates are for the double left turn, since both directions have flashing yellow arrows but the dominant direction, in these situations, tends to take priority (as odd as that sounds; more based on my experience to be honest).
That said, I think situations like this, involving one-way downtown streets, are fairly common. Spokane, WA has a lot of double left and double right turns downtown. I'm sure at least one or two requires yielding to peds and vehicles.
Title: Re: Double left turns with permissive phasing
Post by: RestrictOnTheHanger on April 12, 2020, 12:57:04 PM
Post by: RestrictOnTheHanger on April 12, 2020, 12:57:04 PM
Bethpage/Hicksville, NY
https://maps.app.goo.gl/RSYTE3MHjgfJ6Vm59
https://maps.app.goo.gl/RSYTE3MHjgfJ6Vm59
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 12, 2020, 04:25:17 PM
Post by: jakeroot on April 12, 2020, 04:25:17 PM
Quote from: RestrictOnTheHanger on April 12, 2020, 12:57:04 PM
Bethpage/Hicksville, NY
https://maps.app.goo.gl/RSYTE3MHjgfJ6Vm59
Woah! That's cool. I know that NY has some, but almost all that I've seen do not have an oncoming left, or are turns onto one-way streets. Great find!
Title: Re: Double left turns with permissive phasing
Post by: RestrictOnTheHanger on April 12, 2020, 06:43:03 PM
Post by: RestrictOnTheHanger on April 12, 2020, 06:43:03 PM
Quote from: jakeroot on April 12, 2020, 04:25:17 PMQuote from: RestrictOnTheHanger on April 12, 2020, 12:57:04 PM
Bethpage/Hicksville, NY
https://maps.app.goo.gl/RSYTE3MHjgfJ6Vm59
Woah! That's cool. I know that NY has some, but almost all that I've seen do not have an oncoming left, or are turns onto one-way streets. Great find!
Another one in Garden City, same county(Nassau). A lagging double permissive turn, rare for turns onto a 2 way street.
https://maps.app.goo.gl/aW6ujm7BVdTXSD9y5
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 13, 2020, 12:27:18 AM
Post by: jakeroot on April 13, 2020, 12:27:18 AM
Quote from: RestrictOnTheHanger on April 12, 2020, 06:43:03 PMQuote from: jakeroot on April 12, 2020, 04:25:17 PMQuote from: RestrictOnTheHanger on April 12, 2020, 12:57:04 PM
Bethpage/Hicksville, NY
https://maps.app.goo.gl/RSYTE3MHjgfJ6Vm59
Woah! That's cool. I know that NY has some, but almost all that I've seen do not have an oncoming left, or are turns onto one-way streets. Great find!
Another one in Garden City, same county(Nassau). A lagging double permissive turn, rare for turns onto a 2 way street.
https://maps.app.goo.gl/aW6ujm7BVdTXSD9y5
Another cool find. Although moderately less interesting, given the lack of an opposing left turn. Still, yet another good find in New York.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on April 17, 2020, 10:31:52 AM
Post by: fwydriver405 on April 17, 2020, 10:31:52 AM
Atlanta, GA at Cascade Road on the onramp to I-285 N. (https://www.google.com/maps/@33.7229589,-84.5022648,3a,81.7y,75.29h,78.73t/data=!3m6!1e1!3m4!1sbjh2607dph04ZU1IoyZUgQ!2e0!7i13312!8i6656) Double doghouse configuration, middle lane is a left/thru lane. Not sure how many more double permissive lefts are there in the Atlanta metro area...
If FYA's were to be used at that intersection with the current lane configuration and phasing, would the leftmost signal be an FYA, middle doghouse, and right 3-section signal consisting of all balls?
If FYA's were to be used at that intersection with the current lane configuration and phasing, would the leftmost signal be an FYA, middle doghouse, and right 3-section signal consisting of all balls?
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 17, 2020, 02:19:01 PM
Post by: jakeroot on April 17, 2020, 02:19:01 PM
Quote from: fwydriver405 on April 17, 2020, 10:31:52 AM
Atlanta, GA at Cascade Road on the onramp to I-285 N. (https://www.google.com/maps/@33.7229589,-84.5022648,3a,81.7y,75.29h,78.73t/data=!3m6!1e1!3m4!1sbjh2607dph04ZU1IoyZUgQ!2e0!7i13312!8i6656) Double doghouse configuration, middle lane is a left/thru lane. Not sure how many more double permissive lefts are there in the Atlanta metro area...
If FYA's were to be used at that intersection with the current lane configuration and phasing, would the leftmost signal be an FYA, middle doghouse, and right 3-section signal consisting of all balls?
Looks like it might have been removed: the green arrow is no longer activating for the right-most doghouse, and the option lane arrow has disappeared from the pavement. But the option lane sign is still overhead (see all three in this link (https://goo.gl/maps/TuiqD6dEaQS388wB9)). Honestly, this is how all option lane double left turns onto on-ramps should operate. I've seen some that are split phased. To force through traffic to stop just because you have an option lane seems idiotic, especially with the excellent visibility that left turning traffic would typically have (although the shrubs in this median do hamper visibility a bit).
Typically, with option lanes, I think you'd see it where the left-most signal was an FYA, and middle signal was a doghouse with an FYA instead of regular arrows, and a regular 3-section signal on the right. This is how it's done at this intersection in MN (https://goo.gl/maps/EjD6H22azDyw18Yi7).
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on April 18, 2020, 12:17:47 PM
Post by: Amtrakprod on April 18, 2020, 12:17:47 PM
Quote from: fwydriver405 on April 17, 2020, 10:31:52 AMIt would likely look like this: https://www.google.com/maps/@29.4387288,-98.4609631,3a,28.2y,2.68h,94.06t/data=!3m6!1e1!3m4!1sEnNKghe8vkX2j_TSRMDKgw!2e0!7i16384!8i8192
Atlanta, GA at Cascade Road on the onramp to I-285 N. (https://www.google.com/maps/@33.7229589,-84.5022648,3a,81.7y,75.29h,78.73t/data=!3m6!1e1!3m4!1sbjh2607dph04ZU1IoyZUgQ!2e0!7i13312!8i6656) Double doghouse configuration, middle lane is a left/thru lane. Not sure how many more double permissive lefts are there in the Atlanta metro area...
If FYA's were to be used at that intersection with the current lane configuration and phasing, would the leftmost signal be an FYA, middle doghouse, and right 3-section signal consisting of all balls?
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on April 18, 2020, 12:18:45 PM
Post by: Amtrakprod on April 18, 2020, 12:18:45 PM
Quote from: jakeroot on April 17, 2020, 02:19:01 PMIt also is totally off here: https://www.google.com/maps/@33.7230047,-84.5022569,3a,75y,117.78h,77.02t/data=!3m6!1e1!3m4!1siQe-f0CXUSJHZZ-DNofe2w!2e0!7i16384!8i8192Quote from: fwydriver405 on April 17, 2020, 10:31:52 AM
Atlanta, GA at Cascade Road on the onramp to I-285 N. (https://www.google.com/maps/@33.7229589,-84.5022648,3a,81.7y,75.29h,78.73t/data=!3m6!1e1!3m4!1sbjh2607dph04ZU1IoyZUgQ!2e0!7i13312!8i6656) Double doghouse configuration, middle lane is a left/thru lane. Not sure how many more double permissive lefts are there in the Atlanta metro area...
If FYA's were to be used at that intersection with the current lane configuration and phasing, would the leftmost signal be an FYA, middle doghouse, and right 3-section signal consisting of all balls?
Looks like it might have been removed: the green arrow is no longer activating for the right-most doghouse, and the option lane arrow has disappeared from the pavement. But the option lane sign is still overhead (see all three in this link (https://goo.gl/maps/TuiqD6dEaQS388wB9)). Honestly, this is how all option lane double left turns onto on-ramps should operate. I've seen some that are split phased. To force through traffic to stop just because you have an option lane seems idiotic, especially with the excellent visibility that left turning traffic would typically have (although the shrubs in this median do hamper visibility a bit).
Typically, with option lanes, I think you'd see it where the left-most signal was an FYA, and middle signal was a doghouse with an FYA instead of regular arrows, and a regular 3-section signal on the right. This is how it's done at this intersection in MN (https://goo.gl/maps/EjD6H22azDyw18Yi7).
Title: Re: Double left turns with permissive phasing
Post by: roadfro on April 18, 2020, 01:02:12 PM
Post by: roadfro on April 18, 2020, 01:02:12 PM
Quote from: jakeroot on April 17, 2020, 02:19:01 PM
Looks like it might have been removed: the green arrow is no longer activating for the right-most doghouse, and the option lane arrow has disappeared from the pavement. But the option lane sign is still overhead (see all three in this link (https://goo.gl/maps/TuiqD6dEaQS388wB9)). Honestly, this is how all option lane double left turns onto on-ramps should operate. I've seen some that are split phased. To force through traffic to stop just because you have an option lane seems idiotic, especially with the excellent visibility that left turning traffic would typically have (although the shrubs in this median do hamper visibility a bit).
Well, you're forcing some traffic to stop regardless. In the typical split-phase setup, the opposing through traffic has to stop. In this kind of scenario with an option lane not employing split phasing, any left turning traffic in the option lane waiting for gap in opposing traffic will block any through traffic behind them in the option lane. If this happens to be on a coordinated signal corridor, that permissive feature of the option lane is likely to break up the platoon riding the green wave.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 18, 2020, 03:27:10 PM
Post by: jakeroot on April 18, 2020, 03:27:10 PM
Quote from: roadfro on April 18, 2020, 01:02:12 PMQuote from: jakeroot on April 17, 2020, 02:19:01 PM
Looks like it might have been removed: the green arrow is no longer activating for the right-most doghouse, and the option lane arrow has disappeared from the pavement. But the option lane sign is still overhead (see all three in this link (https://goo.gl/maps/TuiqD6dEaQS388wB9)). Honestly, this is how all option lane double left turns onto on-ramps should operate. I've seen some that are split phased. To force through traffic to stop just because you have an option lane seems idiotic, especially with the excellent visibility that left turning traffic would typically have (although the shrubs in this median do hamper visibility a bit).
Well, you're forcing some traffic to stop regardless. In the typical split-phase setup, the opposing through traffic has to stop. In this kind of scenario with an option lane not employing split phasing, any left turning traffic in the option lane waiting for gap in opposing traffic will block any through traffic behind them in the option lane. If this happens to be on a coordinated signal corridor, that permissive feature of the option lane is likely to break up the platoon riding the green wave.
Split phasing would force all traffic to stop, regardless. Allowing through traffic to proceed might block the option lane, or it might not. Clearly, permissive phasing allows for greater flexibility and much easier coordination. This flexibility is especially clear when you consider the time of day. During rush hour, the option lane might favor left turning traffic. During off hours, it might favor through traffic instead. Again, there is flexibility that you don't have with split-phasing.
The only legit argument might be safety, and even that's a stretch when you consider how good the visibility would be.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 18, 2020, 03:27:36 PM
Post by: jakeroot on April 18, 2020, 03:27:36 PM
Quote from: Amtrakprod on April 18, 2020, 12:18:45 PMQuote from: jakeroot on April 17, 2020, 02:19:01 PMIt also is totally off here: https://www.google.com/maps/@33.7230047,-84.5022569,3a,75y,117.78h,77.02t/data=!3m6!1e1!3m4!1siQe-f0CXUSJHZZ-DNofe2w!2e0!7i16384!8i8192Quote from: fwydriver405 on April 17, 2020, 10:31:52 AM
Atlanta, GA at Cascade Road on the onramp to I-285 N. (https://www.google.com/maps/@33.7229589,-84.5022648,3a,81.7y,75.29h,78.73t/data=!3m6!1e1!3m4!1sbjh2607dph04ZU1IoyZUgQ!2e0!7i13312!8i6656) Double doghouse configuration, middle lane is a left/thru lane. Not sure how many more double permissive lefts are there in the Atlanta metro area...
If FYA's were to be used at that intersection with the current lane configuration and phasing, would the leftmost signal be an FYA, middle doghouse, and right 3-section signal consisting of all balls?
Looks like it might have been removed: the green arrow is no longer activating for the right-most doghouse, and the option lane arrow has disappeared from the pavement. But the option lane sign is still overhead (see all three in this link (https://goo.gl/maps/TuiqD6dEaQS388wB9)). Honestly, this is how all option lane double left turns onto on-ramps should operate. I've seen some that are split phased. To force through traffic to stop just because you have an option lane seems idiotic, especially with the excellent visibility that left turning traffic would typically have (although the shrubs in this median do hamper visibility a bit).
Typically, with option lanes, I think you'd see it where the left-most signal was an FYA, and middle signal was a doghouse with an FYA instead of regular arrows, and a regular 3-section signal on the right. This is how it's done at this intersection in MN (https://goo.gl/maps/EjD6H22azDyw18Yi7).
I saw that as well. No idea what's going on at that intersection.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on April 18, 2020, 04:19:12 PM
Post by: fwydriver405 on April 18, 2020, 04:19:12 PM
Quote from: jakeroot on April 18, 2020, 03:27:36 PMQuote from: Amtrakprod on April 18, 2020, 12:18:45 PMQuote from: jakeroot on April 17, 2020, 02:19:01 PMIt also is totally off here: https://www.google.com/maps/@33.7230047,-84.5022569,3a,75y,117.78h,77.02t/data=!3m6!1e1!3m4!1siQe-f0CXUSJHZZ-DNofe2w!2e0!7i16384!8i8192Quote from: fwydriver405 on April 17, 2020, 10:31:52 AM
Atlanta, GA at Cascade Road on the onramp to I-285 N. (https://www.google.com/maps/@33.7229589,-84.5022648,3a,81.7y,75.29h,78.73t/data=!3m6!1e1!3m4!1sbjh2607dph04ZU1IoyZUgQ!2e0!7i13312!8i6656) Double doghouse configuration, middle lane is a left/thru lane. Not sure how many more double permissive lefts are there in the Atlanta metro area...
If FYA's were to be used at that intersection with the current lane configuration and phasing, would the leftmost signal be an FYA, middle doghouse, and right 3-section signal consisting of all balls?
Looks like it might have been removed: the green arrow is no longer activating for the right-most doghouse, and the option lane arrow has disappeared from the pavement. But the option lane sign is still overhead (see all three in this link (https://goo.gl/maps/TuiqD6dEaQS388wB9)). Honestly, this is how all option lane double left turns onto on-ramps should operate. I've seen some that are split phased. To force through traffic to stop just because you have an option lane seems idiotic, especially with the excellent visibility that left turning traffic would typically have (although the shrubs in this median do hamper visibility a bit).
Typically, with option lanes, I think you'd see it where the left-most signal was an FYA, and middle signal was a doghouse with an FYA instead of regular arrows, and a regular 3-section signal on the right. This is how it's done at this intersection in MN (https://goo.gl/maps/EjD6H22azDyw18Yi7).
I saw that as well. No idea what's going on at that intersection.
Here's the permissive phase as of Sept. 2019 (https://www.google.com/maps/@33.7229332,-84.5019798,3a,68.1y,46.63h,95.27t/data=!3m6!1e1!3m4!1svKDgAqUCoMD3FofoLxTOsA!2e0!7i16384!8i8192). It's hard to see, but there is no arrow where the doghouses are, and the oncoming signal has a green. The middle doghouse is still out in this example...
Title: Re: Double left turns with permissive phasing
Post by: mrsman on April 19, 2020, 09:13:00 AM
Post by: mrsman on April 19, 2020, 09:13:00 AM
Quote from: jakeroot on April 18, 2020, 03:27:10 PMQuote from: roadfro on April 18, 2020, 01:02:12 PMQuote from: jakeroot on April 17, 2020, 02:19:01 PM
Looks like it might have been removed: the green arrow is no longer activating for the right-most doghouse, and the option lane arrow has disappeared from the pavement. But the option lane sign is still overhead (see all three in this link (https://goo.gl/maps/TuiqD6dEaQS388wB9)). Honestly, this is how all option lane double left turns onto on-ramps should operate. I've seen some that are split phased. To force through traffic to stop just because you have an option lane seems idiotic, especially with the excellent visibility that left turning traffic would typically have (although the shrubs in this median do hamper visibility a bit).
Well, you're forcing some traffic to stop regardless. In the typical split-phase setup, the opposing through traffic has to stop. In this kind of scenario with an option lane not employing split phasing, any left turning traffic in the option lane waiting for gap in opposing traffic will block any through traffic behind them in the option lane. If this happens to be on a coordinated signal corridor, that permissive feature of the option lane is likely to break up the platoon riding the green wave.
Split phasing would force all traffic to stop, regardless. Allowing through traffic to proceed might block the option lane, or it might not. Clearly, permissive phasing allows for greater flexibility and much easier coordination. This flexibility is especially clear when you consider the time of day. During rush hour, the option lane might favor left turning traffic. During off hours, it might favor through traffic instead. Again, there is flexibility that you don't have with split-phasing.
The only legit argument might be safety, and even that's a stretch when you consider how good the visibility would be.
Split phasing is almost always worse for overall traffic delay. The exception is if the left turn of both directions are really heavy movements. Split-phasing takes away too much time from the other phases of the intersection.
A well coordinated permissive left turn with an option lane can work really well, and overall far less delay than split phasing. This is especially true if the left turn is lagging and the opposing left is prohibited.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 28, 2020, 04:19:08 AM
Post by: jakeroot on April 28, 2020, 04:19:08 AM
I have located another in California, this one adjacent to the UC Berkeley Campus; it does involve an option lane but is otherwise completely normal:
Eastbound University Ave @ Oxford St, Berkeley, CA (https://goo.gl/maps/ipsnmvjhBRUyMm3H7) (click forward into the intersection to see the other direction showing green).
The left turn is complete with a "LEFT TURNS YIELD" sign on the left.
This installation seems to be the only double left turn yield along public roads outside of SF-proper anywhere in California, at least to my knowledge (I would have said all of California prior to fwydriver405 alerting us to those in SF). The only other one outside of SF-proper is in Santa Clara (https://goo.gl/maps/FnYU4vJ6W9VvRkgDA), but it's from a driveway).
Eastbound University Ave @ Oxford St, Berkeley, CA (https://goo.gl/maps/ipsnmvjhBRUyMm3H7) (click forward into the intersection to see the other direction showing green).
The left turn is complete with a "LEFT TURNS YIELD" sign on the left.
This installation seems to be the only double left turn yield along public roads outside of SF-proper anywhere in California, at least to my knowledge (I would have said all of California prior to fwydriver405 alerting us to those in SF). The only other one outside of SF-proper is in Santa Clara (https://goo.gl/maps/FnYU4vJ6W9VvRkgDA), but it's from a driveway).
Title: Re: Double left turns with permissive phasing
Post by: mrsman on April 28, 2020, 08:58:40 AM
Post by: mrsman on April 28, 2020, 08:58:40 AM
Quote from: jakeroot on April 28, 2020, 04:19:08 AM
I have located another in California, this one adjacent to the UC Berkeley Campus; it does involve an option lane but is otherwise completely normal:
Eastbound University Ave @ Oxford St, Berkeley, CA (https://goo.gl/maps/ipsnmvjhBRUyMm3H7) (click forward into the intersection to see the other direction showing green).
The left turn is complete with a "LEFT TURNS YIELD" sign on the left.
This installation seems to be the only double left turn yield along public roads outside of SF-proper anywhere in California, at least to my knowledge (I would have said all of California prior to fwydriver405 alerting us to those in SF). The only other one outside of SF-proper is in Santa Clara (https://goo.gl/maps/FnYU4vJ6W9VvRkgDA), but it's from a driveway).
While I normally consider a left turn yield on green sign(or similar) language to be somewhat superfluous, I think it is necessary here. Given that permissive double lefts are so rare in California, a lot of people may just simply make the left on green without yielding, if it weren't for the sign. Another oddity about this intersection is that there is no green arrow at all in this direction. Left turns must always yield, there is no protective phase - which again is rare for any CA double left, including the ones in SF and the ones that used to exist in L.A.
Take a look at the intersection of Beverly/Palm/Santa Monica in Beverly Hills:
https://www.google.com/maps/@34.0773825,-118.3957656,3a,75y,142.85h,99.82t/data=!3m6!1e1!3m4!1sTe7bucP3okOd3P-d7JxzgA!2e0!7i13312!8i6656
This intersection is split-phased, Beverly and Palm have greens at separate times. Normally that means that the lefts are protected at all times that there is a green ball showing. But, when a pedestrian has pushed to call to cross the street, the green ball shows without an arrow. So left turners will have to yield to peds here, but not opposing traffic. If a pedestrian did not push the button, the drivers will see a green arrow and have a protected turn.
Now the Beverly side is the double left, and I believe the left is always protected with an arrow from that perspective, but having driven frequently by this intersection for many years when I lived in L.A. (but over 20 years ago), I know that there's a lot to be watchful for. It is kind of unnerving to see a green orb and think? do I have the ROW to turn? why aren't the opposing traffic advancing? do I have to still watch for peds? (A number of years ago there were no arrows at all, so this new setup is definitely better.)
https://www.google.com/maps/@34.0771874,-118.395557,3a,75y,195.66h,92.94t/data=!3m6!1e1!3m4!1sQZki2cevvqUF8YAx51k9Cw!2e0!7i13312!8i6656
A sign like this (below) would probably make things a lot better. This intersection is also split-phased.
https://www.google.com/maps/@39.0153738,-77.0788889,3a,75y,309.57h,101.14t/data=!3m6!1e1!3m4!1seQ-yT27Tmk1cBWHas8h5gA!2e0!7i16384!8i8192
The sign says "left turns yield to pedestrians on green". So it's clear that it allows for split-phasing, but if there is no green arrow, yield to the pedestrians.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on May 05, 2020, 02:53:42 PM
Post by: jakeroot on May 05, 2020, 02:53:42 PM
Quote from: jakeroot on September 18, 2019, 04:00:26 AMQuote from: paulthemapguy on September 17, 2019, 06:17:36 PM
Found one of these for the first time last weekend, on the east side of Sioux Falls, along a section of SD-42 that was reconstructed last year. I'm guessing they're more commonly found in states with universally low traffic volumes.
(https://live.staticflickr.com/65535/48751134258_df577b7585_c.jpg)
Discussions are more enjoyable with photos :)
Nice! I would guess that the side-street in the photo with the dual-FYA setup (Highline Ave) is relatively quiet, which is actually a great reason to install this type of signal: they can allow side-street traffic to clear far quicker than with protected-only phasing, giving more green time to the primary artery (Arrowhead Parkway in this case).
I can't recall hearing of any others in South Dakota, so I'm guessing their state DOT must not have an objection to these types of installs. Especially as this is along a state route. Of course, this installation might have been installed/maintained by Sioux Falls directly, so that's not something I could be sure of.
Following up on Sioux Falls.
There is another at the off-ramp from northbound I-29 at Maple & Russell streets (Exit 81). This one has been in place for as long as street view imagery has been occuring, and the double left turn looks to have been in place since the early 2000s, when the interchange was reconstructed from a diamond into a parclo.
I'm going to assume that, this being the off-ramp from a state-maintained road, that this is a state-maintained intersection. Given this intersection, and other new one at Highline and SD-42 (now on street view (https://goo.gl/maps/bFt1bxak1N6zrcuW7)), I think it's safe to assume that SDDOT has given the thumbs-up to this style of phasing. It would appear that its use is conditional, based on number of lanes and the overall setup (although this is true for regular permissive left turns as well), as other double left turns in Sioux Falls use protected-only phasing (at least for those that I've located).
As a side-note: this is definitely one of my favorite interchanges in the US. There is something very elegant about the way it was designed (the placement of the free-flow ramps especially). South Dakota also has excellent signal placement, and the northbound off-ramp has a double permissive left. Just a lot of "good" things going on here, from my perspective.
https://goo.gl/maps/essAqyJ3UehQjUQe6
(https://i.imgur.com/h0WD0uz.png)
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on May 05, 2020, 06:45:25 PM
Post by: jakeroot on May 05, 2020, 06:45:25 PM
Quote from: mrsman on April 28, 2020, 08:58:40 AMQuote from: jakeroot on April 28, 2020, 04:19:08 AM
I have located another in California, this one adjacent to the UC Berkeley Campus; it does involve an option lane but is otherwise completely normal:
Eastbound University Ave @ Oxford St, Berkeley, CA (https://goo.gl/maps/ipsnmvjhBRUyMm3H7) (click forward into the intersection to see the other direction showing green).
The left turn is complete with a "LEFT TURNS YIELD" sign on the left.
This installation seems to be the only double left turn yield along public roads outside of SF-proper anywhere in California, at least to my knowledge (I would have said all of California prior to fwydriver405 alerting us to those in SF). The only other one outside of SF-proper is in Santa Clara (https://goo.gl/maps/FnYU4vJ6W9VvRkgDA), but it's from a driveway).
While I normally consider a left turn yield on green sign (or similar) language to be somewhat superfluous, I think it is necessary here. Given that permissive double lefts are so rare in California, a lot of people may just simply make the left on green without yielding, if it weren't for the sign. Another oddity about this intersection is that there is no green arrow at all in this direction. Left turns must always yield, there is no protective phase - which again is rare for any CA double left, including the ones in SF and the ones that used to exist in L.A.
Take a look at the intersection of Beverly/Palm/Santa Monica in Beverly Hills:
https://www.google.com/maps/@34.0773825,-118.3957656,3a,75y,142.85h,99.82t/data=!3m6!1e1!3m4!1sTe7bucP3okOd3P-d7JxzgA!2e0!7i13312!8i6656
This intersection is split-phased, Beverly and Palm have greens at separate times. Normally that means that the lefts are protected at all times that there is a green ball showing. But, when a pedestrian has pushed to call to cross the street, the green ball shows without an arrow. So left turners will have to yield to peds here, but not opposing traffic. If a pedestrian did not push the button, the drivers will see a green arrow and have a protected turn.
Now the Beverly side is the double left, and I believe the left is always protected with an arrow from that perspective, but having driven frequently by this intersection for many years when I lived in L.A. (but over 20 years ago), I know that there's a lot to be watchful for. It is kind of unnerving to see a green orb and think? do I have the ROW to turn? why aren't the opposing traffic advancing? do I have to still watch for peds? (A number of years ago there were no arrows at all, so this new setup is definitely better.)
https://www.google.com/maps/@34.0771874,-118.395557,3a,75y,195.66h,92.94t/data=!3m6!1e1!3m4!1sQZki2cevvqUF8YAx51k9Cw!2e0!7i13312!8i6656
A sign like this (below) would probably make things a lot better. This intersection is also split-phased.
https://www.google.com/maps/@39.0153738,-77.0788889,3a,75y,309.57h,101.14t/data=!3m6!1e1!3m4!1seQ-yT27Tmk1cBWHas8h5gA!2e0!7i16384!8i8192
The sign says "left turns yield to pedestrians on green". So it's clear that it allows for split-phasing, but if there is no green arrow, yield to the pedestrians.
Not sure why I keep missing your posts.
Seems that, of all the double permissive left turns without dedicated turn lanes (so maybe one dedicated left turn lane, adjacent to an optional left/straight lane), they are largely permissive-only. The exception seems to be those onto one-way streets, where a lagging green arrow is most common.
An example of the above (permissive-only) is in Seattle, from NE 44th onto Montlake Blvd:
https://goo.gl/maps/5QScXHpcBvYJTQkw7
In 98% of municipalities, this would be split-phased, but it is permissive-only here. An advanced left could be used, but there is no reason as there is little oncoming traffic. Most of the time, this intersection operates as a T-intersection (practically, anyways). At any rate, a "LEFT TURNS MUST YIELD" would be a nice sign, short of changing the operation of the intersection altogether.
I have not seen an intersection operate like those two in Los Angeles and Maryland, but it is a very logical setup for an intersection that could otherwise be very low capacity when a pedestrian push-button is selected. I would be very interested to know if, in those municipalities that setup intersections in this manner, if it's acceptable to use permissive phasing with two left turn lanes, but only when the pedestrian walk sign is on (so traffic is only yielding to pedestrians, not through traffic). If the double left turn is the heaviest movement of the split-phase, and a pedestrian wanted to cross along that edge of the intersection (conflicting with the double left turn), that would, in a typical split-phase intersection, force the double left turn to wait for the entire walk cycle, all the while waiting for oncoming traffic (perhaps no one coming at all).
In Federal Way, WA, there is an offset intersection that is ordinarily split-phased, but has flashing yellow arrows for the intersecting streets when the walk signs are activated (very similar to those in LA and Maryland, but a little different). I took a video a few years (and a few pounds :-D) ago. What I don't recall is whether both walk signs activate simultaneously, or if one of the oncoming directions still has a green light during the walk phase. I need to go back and get another video!
https://youtu.be/jEVhAABx0q4
Title: Re: Double left turns with permissive phasing
Post by: mrsman on May 06, 2020, 07:10:00 PM
Post by: mrsman on May 06, 2020, 07:10:00 PM
Quote from: jakeroot on May 05, 2020, 06:45:25 PMQuote from: mrsman on April 28, 2020, 08:58:40 AMQuote from: jakeroot on April 28, 2020, 04:19:08 AM
I have located another in California, this one adjacent to the UC Berkeley Campus; it does involve an option lane but is otherwise completely normal:
Eastbound University Ave @ Oxford St, Berkeley, CA (https://goo.gl/maps/ipsnmvjhBRUyMm3H7) (click forward into the intersection to see the other direction showing green).
The left turn is complete with a "LEFT TURNS YIELD" sign on the left.
This installation seems to be the only double left turn yield along public roads outside of SF-proper anywhere in California, at least to my knowledge (I would have said all of California prior to fwydriver405 alerting us to those in SF). The only other one outside of SF-proper is in Santa Clara (https://goo.gl/maps/FnYU4vJ6W9VvRkgDA), but it's from a driveway).
While I normally consider a left turn yield on green sign (or similar) language to be somewhat superfluous, I think it is necessary here. Given that permissive double lefts are so rare in California, a lot of people may just simply make the left on green without yielding, if it weren't for the sign. Another oddity about this intersection is that there is no green arrow at all in this direction. Left turns must always yield, there is no protective phase - which again is rare for any CA double left, including the ones in SF and the ones that used to exist in L.A.
Take a look at the intersection of Beverly/Palm/Santa Monica in Beverly Hills:
https://www.google.com/maps/@34.0773825,-118.3957656,3a,75y,142.85h,99.82t/data=!3m6!1e1!3m4!1sTe7bucP3okOd3P-d7JxzgA!2e0!7i13312!8i6656
This intersection is split-phased, Beverly and Palm have greens at separate times. Normally that means that the lefts are protected at all times that there is a green ball showing. But, when a pedestrian has pushed to call to cross the street, the green ball shows without an arrow. So left turners will have to yield to peds here, but not opposing traffic. If a pedestrian did not push the button, the drivers will see a green arrow and have a protected turn.
Now the Beverly side is the double left, and I believe the left is always protected with an arrow from that perspective, but having driven frequently by this intersection for many years when I lived in L.A. (but over 20 years ago), I know that there's a lot to be watchful for. It is kind of unnerving to see a green orb and think? do I have the ROW to turn? why aren't the opposing traffic advancing? do I have to still watch for peds? (A number of years ago there were no arrows at all, so this new setup is definitely better.)
https://www.google.com/maps/@34.0771874,-118.395557,3a,75y,195.66h,92.94t/data=!3m6!1e1!3m4!1sQZki2cevvqUF8YAx51k9Cw!2e0!7i13312!8i6656
A sign like this (below) would probably make things a lot better. This intersection is also split-phased.
https://www.google.com/maps/@39.0153738,-77.0788889,3a,75y,309.57h,101.14t/data=!3m6!1e1!3m4!1seQ-yT27Tmk1cBWHas8h5gA!2e0!7i16384!8i8192
The sign says "left turns yield to pedestrians on green". So it's clear that it allows for split-phasing, but if there is no green arrow, yield to the pedestrians.
Not sure why I keep missing your posts.
Seems that, of all the double permissive left turns without dedicated turn lanes (so maybe one dedicated left turn lane, adjacent to an optional left/straight lane), they are largely permissive-only. The exception seems to be those onto one-way streets, where a lagging green arrow is most common.
An example of the above (permissive-only) is in Seattle, from NE 44th onto Montlake Blvd:
https://goo.gl/maps/5QScXHpcBvYJTQkw7
In 98% of municipalities, this would be split-phased, but it is permissive-only here. An advanced left could be used, but there is no reason as there is little oncoming traffic. Most of the time, this intersection operates as a T-intersection (practically, anyways). At any rate, a "LEFT TURNS MUST YIELD" would be a nice sign, short of changing the operation of the intersection altogether.
I have not seen an intersection operate like those two in Los Angeles and Maryland, but it is a very logical setup for an intersection that could otherwise be very low capacity when a pedestrian push-button is selected. I would be very interested to know if, in those municipalities that setup intersections in this manner, if it's acceptable to use permissive phasing with two left turn lanes, but only when the pedestrian walk sign is on (so traffic is only yielding to pedestrians, not through traffic). If the double left turn is the heaviest movement of the split-phase, and a pedestrian wanted to cross along that edge of the intersection (conflicting with the double left turn), that would, in a typical split-phase intersection, force the double left turn to wait for the entire walk cycle, all the while waiting for oncoming traffic (perhaps no one coming at all).
In Federal Way, WA, there is an offset intersection that is ordinarily split-phased, but has flashing yellow arrows for the intersecting streets when the walk signs are activated (very similar to those in LA and Maryland, but a little different). I took a video a few years (and a few pounds :-D) ago. What I don't recall is whether both walk signs activate simultaneously, or if one of the oncoming directions still has a green light during the walk phase. I need to go back and get another video!
https://youtu.be/jEVhAABx0q4
For most split-phased intersections, especially, when the split-phased side is a relatively narrow street, in my opinion it would be better if only one of the crosswalks were provided (i.e. prohibit crossing on one side of the street, the side with the busiest left turns). In that sense, we can limit the amount of time of the split-phasing dramatically.
So if the westbound to southbound left is heavier than eastbound to northbound, make the westbound left the first left and allow pedestrians to only cross on the north side of the intersection. During this first phase, westbound to southbound will have a protected left and pedestrians can cross. During the second phase, eastbound to northbound, those drivers will have to yield to the pedestrians, but since it is the last part of the signal phase, there should be few pedestrians in the way. Left turns should yield to pedestrians (only) and not oncoming traffic, but there should be no green arrow for this and it should be clearly delineated as such.
As far as your question regarding whether CA or MD allows a double left against pedestrians but not against traffic, I am not sure that exists. Generally both jurisdictions do not allow permissive double lefts, although there are some exceptions that are noted on this thread. I don't believe there is an exception to allow a permissive left on a two way street against pedestrians, but not against vehicular traffic. Of course, if we were on a one-way street, or a T intersection, where there is no possibility of oncoming vehicular traffic, double lefts against a pedestrian crossing are common and allowed in the permissive setting.
One could surmise that the MD situation [allowing a split phase with a yield to pedestrians] could exist on a split-phase where one or both sides has a double left (or left + option lane left). But to my knowledge, nothing like "yield to pedestrians on green" has been implemented at an intersection with a double left. It is also not helpful that MD still doesn't employ the flashing yellow arrow, which could make some of these situations more tenable. It should be noted that at the Connecticut/Saul intersection that I posted earlier, the left that has to yield to pedestrians is on the side with far less traffic. The busier left of the split phase does not face a pedestrian crossing at all.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on May 07, 2020, 05:49:07 PM
Post by: jakeroot on May 07, 2020, 05:49:07 PM
Quote from: mrsman on May 06, 2020, 07:10:00 PM
For most split-phased intersections, especially, when the split-phased side is a relatively narrow street, in my opinion it would be better if only one of the crosswalks were provided (i.e. prohibit crossing on one side of the street, the side with the busiest left turns). In that sense, we can limit the amount of time of the split-phasing dramatically.
So if the westbound to southbound left is heavier than eastbound to northbound, make the westbound left the first left and allow pedestrians to only cross on the north side of the intersection. During this first phase, westbound to southbound will have a protected left and pedestrians can cross. During the second phase, eastbound to northbound, those drivers will have to yield to the pedestrians, but since it is the last part of the signal phase, there should be few pedestrians in the way. Left turns should yield to pedestrians (only) and not oncoming traffic, but there should be no green arrow for this and it should be clearly delineated as such.
As far as your question regarding whether CA or MD allows a double left against pedestrians but not against traffic, I am not sure that exists. Generally both jurisdictions do not allow permissive double lefts, although there are some exceptions that are noted on this thread. I don't believe there is an exception to allow a permissive left on a two way street against pedestrians, but not against vehicular traffic. Of course, if we were on a one-way street, or a T intersection, where there is no possibility of oncoming vehicular traffic, double lefts against a pedestrian crossing are common and allowed in the permissive setting.
One could surmise that the MD situation [allowing a split phase with a yield to pedestrians] could exist on a split-phase where one or both sides has a double left (or left + option lane left). But to my knowledge, nothing like "yield to pedestrians on green" has been implemented at an intersection with a double left. It is also not helpful that MD still doesn't employ the flashing yellow arrow, which could make some of these situations more tenable. It should be noted that at the Connecticut/Saul intersection that I posted earlier, the left that has to yield to pedestrians is on the side with far less traffic. The busier left of the split phase does not face a pedestrian crossing at all.
I think it is far more standard for split-phased intersections to have only one crosswalk along the edge adjacent to the heavier leg's through movement, but I appreciate it when agencies try and figure something else out.
I went back and filmed the intersection in that video above, so it shows the whole phase. Turns out that when someone activates the crosswalk, and the left-facing FYA activates, the oncoming green signal (for left and right turns) is also active; you can see this happening in the second half of the video, when I cross the crosswalk on the right. So other than right-turning traffic having a green signal, every other movement occurs simultaneously. This seems to miss the point of split-phasing, and the regulatory signage for the FYA does not indicate that yielding to oncoming traffic is required.
As noted by a commentor, the solid yellow to indicate the end of the permissive FYA phase is below the FYA (see 0:18). I suppose that's a bit odd.
https://youtu.be/qA7YCmfNhv4
Title: Re: Double left turns with permissive phasing
Post by: mrsman on May 08, 2020, 06:29:15 PM
Post by: mrsman on May 08, 2020, 06:29:15 PM
That does seem to be a weird setup, but apparently safe. Hope it works well for Federal Way.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on June 10, 2020, 12:28:55 AM
Post by: jakeroot on June 10, 2020, 12:28:55 AM
Another in Garden City, Kansas. Centre lane is optional:
https://goo.gl/maps/SGYFPKAxyEWgAHqv7
New install around 2011 or 2012, from the looks of it.
https://goo.gl/maps/SGYFPKAxyEWgAHqv7
New install around 2011 or 2012, from the looks of it.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on June 29, 2020, 12:24:01 AM
Post by: jakeroot on June 29, 2020, 12:24:01 AM
I'm in Indiana for a couple days, and spotted an intersection with two.
East 116th St @ IKEA Way (https://goo.gl/maps/2gjAMsEuQRD46w8C6)
The eastbound double left turn is now an FYA, but remains permissive.
When I went through it earlier today, at about 1300, the flashing yellow arrows were active. No idea if they were switched so they could be operated based on the time of day.
East 116th St @ IKEA Way (https://goo.gl/maps/2gjAMsEuQRD46w8C6)
The eastbound double left turn is now an FYA, but remains permissive.
When I went through it earlier today, at about 1300, the flashing yellow arrows were active. No idea if they were switched so they could be operated based on the time of day.
Title: Re: Double left turns with permissive phasing
Post by: stevashe on June 29, 2020, 02:08:21 PM
Post by: stevashe on June 29, 2020, 02:08:21 PM
Quote from: Amtrakprod on April 18, 2020, 12:18:45 PMQuote from: jakeroot on April 17, 2020, 02:19:01 PMIt also is totally off here: https://www.google.com/maps/@33.7230047,-84.5022569,3a,75y,117.78h,77.02t/data=!3m6!1e1!3m4!1siQe-f0CXUSJHZZ-DNofe2w!2e0!7i16384!8i8192Quote from: fwydriver405 on April 17, 2020, 10:31:52 AM
Atlanta, GA at Cascade Road on the onramp to I-285 N. (https://www.google.com/maps/@33.7229589,-84.5022648,3a,81.7y,75.29h,78.73t/data=!3m6!1e1!3m4!1sbjh2607dph04ZU1IoyZUgQ!2e0!7i13312!8i6656) Double doghouse configuration, middle lane is a left/thru lane. Not sure how many more double permissive lefts are there in the Atlanta metro area...
If FYA's were to be used at that intersection with the current lane configuration and phasing, would the leftmost signal be an FYA, middle doghouse, and right 3-section signal consisting of all balls?
Looks like it might have been removed: the green arrow is no longer activating for the right-most doghouse, and the option lane arrow has disappeared from the pavement. But the option lane sign is still overhead (see all three in this link (https://goo.gl/maps/TuiqD6dEaQS388wB9)). Honestly, this is how all option lane double left turns onto on-ramps should operate. I've seen some that are split phased. To force through traffic to stop just because you have an option lane seems idiotic, especially with the excellent visibility that left turning traffic would typically have (although the shrubs in this median do hamper visibility a bit).
Typically, with option lanes, I think you'd see it where the left-most signal was an FYA, and middle signal was a doghouse with an FYA instead of regular arrows, and a regular 3-section signal on the right. This is how it's done at this intersection in MN (https://goo.gl/maps/EjD6H22azDyw18Yi7).
The new most recent streetview from March 2020 shows the arrow is back on! https://goo.gl/maps/FX9n1X2jMCCkDn6G8 I assume this wasn't available at the time those messages were posted. Since it's back, I'm thinking the light may have just been burnt out. It also suggests that the lane is indeed still an option lane since the sign was also left up, they must have just opted not to reinstall the arrows after repaving for whatever reason.
Quote from: jakeroot on April 13, 2020, 12:27:18 AMQuote from: RestrictOnTheHanger on April 12, 2020, 06:43:03 PM
Another one in Garden City, same county(Nassau). A lagging double permissive turn, rare for turns onto a 2 way street.
https://maps.app.goo.gl/aW6ujm7BVdTXSD9y5
Another cool find. Although moderately less interesting, given the lack of an opposing left turn. Still, yet another good find in New York.
What I find interesting about this intersection is the double left from Oak St has only 1 receiving lane on Commercial Ave! :-o Seems like an accident waiting to happen for anyone that doesn't know they have to merge within the intersection. Did anyone else notice that?
Title: Re: Double left turns with permissive phasing
Post by: kphoger on June 29, 2020, 03:04:28 PM
Post by: kphoger on June 29, 2020, 03:04:28 PM
Quote from: stevashe on June 29, 2020, 02:08:21 PM
What I find interesting about this intersection is the double left from Oak St has only 1 receiving lane on Commercial Ave! :-o Seems like an accident waiting to happen for anyone that doesn't know they have to merge within the intersection. Did anyone else notice that?
Tell you what, I wouldn't to be parallel-parked where those pickups are!
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on July 16, 2020, 10:25:04 AM
Post by: fwydriver405 on July 16, 2020, 10:25:04 AM
Thought I'd NEVER see a double permissive left in New England in person ever. This is in Providence RI at the Empire and Fountain St (https://goo.gl/maps/T9CLgeuQrqc6YBGL7) intersection. Left + left-thru configuration with a 4-section Bimodal PPLT (This signal seems to be very common in RI as much as it is in NH)
Title: Re: Double left turns with permissive phasing
Post by: Ned Weasel on July 16, 2020, 10:35:52 AM
Post by: Ned Weasel on July 16, 2020, 10:35:52 AM
Quote from: stevashe on June 29, 2020, 02:08:21 PMQuote from: jakeroot on April 13, 2020, 12:27:18 AMQuote from: RestrictOnTheHanger on April 12, 2020, 06:43:03 PM
Another one in Garden City, same county(Nassau). A lagging double permissive turn, rare for turns onto a 2 way street.
https://maps.app.goo.gl/aW6ujm7BVdTXSD9y5
Another cool find. Although moderately less interesting, given the lack of an opposing left turn. Still, yet another good find in New York.
What I find interesting about this intersection is the double left from Oak St has only 1 receiving lane on Commercial Ave! :-o Seems like an accident waiting to happen for anyone that doesn't know they have to merge within the intersection. Did anyone else notice that?
What the hell!? What traffic engineer allowed that!? If the receiving area was wider, one could argue that it's two unstriped lanes merging down to one after the intersection (which is actually a thing: https://goo.gl/maps/UkpHrMMGTGRrxzCi7), but from what I can measure on Google Maps, there's only 17 feet between those lane stripes.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 16, 2020, 03:17:52 PM
Post by: jakeroot on July 16, 2020, 03:17:52 PM
Quote from: fwydriver405 on July 16, 2020, 10:25:04 AM
Thought I'd NEVER see a double permissive left in New England in person ever. This is in Providence RI at the Empire and Fountain St (https://goo.gl/maps/T9CLgeuQrqc6YBGL7) intersection. Left + left-thru configuration with a 4-section Bimodal PPLT (This signal seems to be very common in RI as much as it is in NH)
Intriguing, especially given how new it is! Must be a lagging green arrow? Typically, with turns onto one-way streets in downtown areas in similar situations, the green arrow comes on at the end. Could still be a bimodal signal, that displays simultaneous yellow orb and arrow at the very end of the cycle.
Is New York not usually part of New England? Because NYS seems to have quite a few (note post above mine). There's also been at least one in Mass at one point, as well as that "unsignalized" example in Brunswick, ME you posted about on page 14.
Still, probably the part of the country with the least. Several examples have now been located in California, which is the other area of the country I would have grouped in with New England. Other than that, I'm not aware of any in Utah, Montana, or Wyoming, and I don't believe Florida has any examples anymore. I'm 98% sure every other state has at least one example somewhere. MN is a weird example, with tons of double-left FYA signals, but I don't know if they actually use the flashing phase.
Title: Re: Double left turns with permissive phasing
Post by: kphoger on July 16, 2020, 03:23:29 PM
Post by: kphoger on July 16, 2020, 03:23:29 PM
Quote from: jakeroot on July 16, 2020, 03:17:52 PM
Is New York not usually part of New England?
(https://upload.wikimedia.org/wikipedia/commons/2/2e/New_England_USA.svg)
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 16, 2020, 03:25:22 PM
Post by: jakeroot on July 16, 2020, 03:25:22 PM
Quote from: stridentweasel on July 16, 2020, 10:35:52 AMQuote from: stevashe on June 29, 2020, 02:08:21 PMQuote from: jakeroot on April 13, 2020, 12:27:18 AMQuote from: RestrictOnTheHanger on April 12, 2020, 06:43:03 PM
Another one in Garden City, same county(Nassau). A lagging double permissive turn, rare for turns onto a 2 way street.
https://maps.app.goo.gl/aW6ujm7BVdTXSD9y5
Another cool find. Although moderately less interesting, given the lack of an opposing left turn. Still, yet another good find in New York.
What I find interesting about this intersection is the double left from Oak St has only 1 receiving lane on Commercial Ave! :-o Seems like an accident waiting to happen for anyone that doesn't know they have to merge within the intersection. Did anyone else notice that?
What the hell!? What traffic engineer allowed that!? If the receiving area was wider, one could argue that it's two unstriped lanes merging down to one after the intersection (which is actually a thing: https://goo.gl/maps/UkpHrMMGTGRrxzCi7), but from what I can measure on Google Maps, there's only 17 feet between those lane stripes.
Check out this example (https://youtu.be/q3dditaRyB8) of a double-left followed by a merge (jump to 0:55). Insanely short. But still nothing compared to merging in the turn :-D.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 16, 2020, 03:42:42 PM
Post by: jakeroot on July 16, 2020, 03:42:42 PM
Quote from: kphoger on July 16, 2020, 03:23:29 PMQuote from: jakeroot on July 16, 2020, 03:17:52 PM
Is New York not usually part of New England?
(https://upload.wikimedia.org/wikipedia/commons/2/2e/New_England_USA.svg)
Thanks. It's just funny to me think of NYS as being so culturally disassociated from "New England" that fwydriver405 would be so stunned to find an example of a double permissive left, when there are countless examples in NYS, many being far less than a day's drive from all but the northern reaches of Maine. For the purposes of this thread, I would have absolutely grouped NYS with other states in that region.
That would be called "the Northeast", I suppose.
Title: Re: Double left turns with permissive phasing
Post by: webny99 on July 16, 2020, 03:46:48 PM
Post by: webny99 on July 16, 2020, 03:46:48 PM
Quote from: jakeroot on July 16, 2020, 03:17:52 PM
Is New York not usually part of New England? Because NYS seems to have quite a few (note post above mine).
Uh, no, definitely not. Either Northeast or Mid-Atlantic, but never New England. That's exclusive to the six small states east of us.
Also, what post? I'm not seeing any NY examples posted... "post above [yours]" turned out to be pretty vague. :-D
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 16, 2020, 04:42:09 PM
Post by: jakeroot on July 16, 2020, 04:42:09 PM
Quote from: webny99 on July 16, 2020, 03:46:48 PMQuote from: jakeroot on July 16, 2020, 03:17:52 PM
Is New York not usually part of New England? Because NYS seems to have quite a few (note post above mine).
Uh, no, definitely not. Either Northeast or Mid-Atlantic, but never New England. That's exclusive to the six small states east of us.
Also, what post? I'm not seeing any NY examples posted... "post above [yours]" turned out to be pretty vague. :-D
Yes, I got it. New England is also in the Northeast but not all Northeast states are in New England. Or maybe New York is in the Mid-Atlantic region? The fact that you, as a NYS resident, aren't even sure what region it's in with total certainty, shows that it may not be as clear-cut as some make it out to be.
Reply #443; the original quote (by RestrictOnTheHangar) has an example in Nassau County. There are others on Long Island (such as here (https://goo.gl/maps/cyGHrGQ8xHpNft4M6) and here (https://goo.gl/maps/YCVr7VZmyLW25dNF8)) and other parts of NYC. Flatbush Ave has at least two (@ Tillary & Ave U), and another at Centre & Chambers in Manhattan; I think there's at least one upstate somewhere.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on July 16, 2020, 05:28:10 PM
Post by: Amtrakprod on July 16, 2020, 05:28:10 PM
Quote from: jakeroot on July 16, 2020, 03:42:42 PMQuote from: kphoger on July 16, 2020, 03:23:29 PMQuote from: jakeroot on July 16, 2020, 03:17:52 PM
Is New York not usually part of New England?
(https://upload.wikimedia.org/wikipedia/commons/2/2e/New_England_USA.svg)
Thanks. It's just funny to me think of NYS as being so culturally disassociated from "New England" that fwydriver405 would be so stunned to find an example of a double permissive left, when there are countless examples in NYS, many being far less than a day's drive from all but the northern reaches of Maine. For the purposes of this thread, I would have absolutely grouped NYS with other states in that region.
That would be called "the Northeast", I suppose.
You'll be mocked pretty hard if you come to the real New England and say that NYS is part of it haha. They don't like us and we don't like them, the red sox rivalry didn't help.
Title: Re: Double left turns with permissive phasing
Post by: webny99 on July 16, 2020, 06:02:05 PM
Post by: webny99 on July 16, 2020, 06:02:05 PM
Quote from: jakeroot on July 16, 2020, 04:42:09 PM
Yes, I got it. New England is also in the Northeast but not all Northeast states are in New England. Or maybe New York is in the Mid-Atlantic region? The fact that you, as a NYS resident, aren't even sure what region it's in with total certainty, shows that it may not be as clear-cut as some make it out to be.
I'm 100% sure that New York is in the Northeast. New England and Mid-Atlantic are both subsets of the Northeast. NY fits into the latter if you have to choose, but it's a bit hard to call Buffalo "Mid-Atlantic", so Northeast is really the only safe bet for the state as a whole.
I guess you could also argue that New York is simply its own subset of the Northeast: it's almost as big as New England, after all.
Quote from: jakeroot on July 16, 2020, 04:42:09 PM
Reply #443; the original quote (by RestrictOnTheHangar) has an example in Nassau County.
Got it, thank you. I had clicked on his link, but overlooked the one in the nested quote.
Title: Re: Double left turns with permissive phasing
Post by: NoGoodNamesAvailable on July 16, 2020, 06:18:00 PM
Post by: NoGoodNamesAvailable on July 16, 2020, 06:18:00 PM
Quote from: stridentweasel on July 16, 2020, 10:35:52 AM
What the hell!? What traffic engineer allowed that!? If the receiving area was wider, one could argue that it's two unstriped lanes merging down to one after the intersection (which is actually a thing: https://goo.gl/maps/UkpHrMMGTGRrxzCi7), but from what I can measure on Google Maps, there's only 17 feet between those lane stripes.
Honestly, par for the course for Nassau county. Plenty of bad engineering to be found.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 16, 2020, 06:22:36 PM
Post by: jakeroot on July 16, 2020, 06:22:36 PM
Quote from: NoGoodNamesAvailable on July 16, 2020, 06:18:00 PMQuote from: stridentweasel on July 16, 2020, 10:35:52 AM
What the hell!? What traffic engineer allowed that!? If the receiving area was wider, one could argue that it's two unstriped lanes merging down to one after the intersection (which is actually a thing: https://goo.gl/maps/UkpHrMMGTGRrxzCi7), but from what I can measure on Google Maps, there's only 17 feet between those lane stripes.
Honestly, par for the course for Nassau county. Plenty of bad engineering to be found.
Maybe so, although Nassau County has quite a few examples of what I'm looking for in this thread. So it's not all bad! Although it depends on your perspective, granted.
Quote from: webny99 on July 16, 2020, 06:02:05 PM
I guess you could also argue that New York is simply its own subset of the Northeast: it's almost as big as New England, after all.
I vote for this option. :-D
Title: Re: Double left turns with permissive phasing
Post by: mrsman on July 16, 2020, 10:33:18 PM
Post by: mrsman on July 16, 2020, 10:33:18 PM
Quote from: jakeroot on July 16, 2020, 04:42:09 PMQuote from: webny99 on July 16, 2020, 03:46:48 PMQuote from: jakeroot on July 16, 2020, 03:17:52 PM
Is New York not usually part of New England? Because NYS seems to have quite a few (note post above mine).
Uh, no, definitely not. Either Northeast or Mid-Atlantic, but never New England. That's exclusive to the six small states east of us.
Also, what post? I'm not seeing any NY examples posted... "post above [yours]" turned out to be pretty vague. :-D
Yes, I got it. New England is also in the Northeast but not all Northeast states are in New England. Or maybe New York is in the Mid-Atlantic region? The fact that you, as a NYS resident, aren't even sure what region it's in with total certainty, shows that it may not be as clear-cut as some make it out to be.
Reply #443; the original quote (by RestrictOnTheHangar) has an example in Nassau County. There are others on Long Island (such as here (https://goo.gl/maps/cyGHrGQ8xHpNft4M6) and here (https://goo.gl/maps/YCVr7VZmyLW25dNF8)) and other parts of NYC. Flatbush Ave has at least two (@ Tillary & Ave U), and another at Centre & Chambers in Manhattan; I think there's at least one upstate somewhere.
This issue is confused as well on this forum given the way that the states are grouped into different regions. Traditionally, the states were divided as such:
New England: CT, RI, MA, VT, NH, ME
Mid-Atlantic: NY, NJ, PA
Southeast: DE*, MD, VA, WV, plus other southeastern states.
* DE is sometimes grouped with Mid-Atlantic.
The reason why MD, VA, WV were grouped in the southeast was because they are states that are south of the Mason-Dixon line. But today, those states have more of a northeastern feel, especially MD.
This forum groups all of the New England and Mid-Atlantic states as Northeastern. This makes for a huge group with more posts than any other region. IMO, it would have been better to keep this split as two regions: New England and Mid-Atlantic. The number of posts in each of these regions would be more manageable.
The forum groups DE, MD, VA, and WV as the Mid-Atlantic group. These states do belong together as a group as they are distinct from the more southern states and the traditoinal Mid-Atlantic states of NY, NJ, and PA. The problem is that the name doesn't really fit the group. A better name would be "near south" or the now popular "Delmarva".
In short, NY, NJ, PA are Mid-Atlantic states even though in this forum MD, VA, and WV are grouped (incorrectly) as Mid-Atlantic states. Given the new political realities in those three states, they are disctinct from other southern states.
Title: Re: Double left turns with permissive phasing
Post by: US 89 on July 17, 2020, 01:43:03 AM
Post by: US 89 on July 17, 2020, 01:43:03 AM
Just remembered a double permissive left I encountered in Parker, Colorado about a month ago. It caught me by surprise, as I don’t routinely drive in areas with them.
https://goo.gl/maps/89js24aYYDRwa3sV8
I am not usually a fan of these, but if we’re going to have them I’d say this type of environment is where they fit best: wide open suburban arterials with good sight lines.
https://goo.gl/maps/89js24aYYDRwa3sV8
I am not usually a fan of these, but if we’re going to have them I’d say this type of environment is where they fit best: wide open suburban arterials with good sight lines.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on July 17, 2020, 07:56:48 AM
Post by: mrsman on July 17, 2020, 07:56:48 AM
Quote from: US 89 on July 17, 2020, 01:43:03 AM
Just remembered a double permissive left I encountered in Parker, Colorado about a month ago. It caught me by surprise, as I don't routinely drive in areas with them.
https://goo.gl/maps/89js24aYYDRwa3sV8
I am not usually a fan of these, but if we're going to have them I'd say this type of environment is where they fit best: wide open suburban arterials with good sight lines.
While this intersection is signalized with 4 aspect FYA signals, GSV shows a red arrow at the same time as green orb in one of the directions. To me, it seems like the signal is probably operating with TOD changes. During part of the day, protected only, and at other parts of the day allowing for the permissive FYA indication.
I feel that this is a reasonable compromise. In many areas that are uncomfortable with allowing a double permissive turn, they could restrict it based on time of day (or actual traffic levels based on sensor readings). At busier times, it's a regular double left with protected only operation. At off times, permissive turns are allowed.
To take it one step further, during off times, the DOT can restrict traffic so that only one of the two left turn lanes is used. A red X lane (similar to what is used on reversible roads) can restrict traffic from using the rightmost of the two dual left turn lanes during times of permissive signal operation. I don't know of any place that does that, but the possibility exists. At any event, this avoids the annoying necessity of waiting forever for a green arrow at 2 a.m.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on July 17, 2020, 09:03:45 AM
Post by: fwydriver405 on July 17, 2020, 09:03:45 AM
Quote from: jakeroot on July 16, 2020, 03:17:52 PM
Intriguing, especially given how new it is! Must be a lagging green arrow? Typically, with turns onto one-way streets in downtown areas in similar situations, the green arrow comes on at the end. Could still be a bimodal signal, that displays simultaneous yellow orb and arrow at the very end of the cycle.
The green arrow is actually leading (bimodal yellow+green arrow) at this intersection - was expecting it to be a lagging green arrow. Could it be because of the short distance between intersections?
Quote from: jakeroot on July 16, 2020, 03:17:52 PM
Thanks. It's just funny to me think of NYS as being so culturally disassociated from "New England" that fwydriver405 would be so stunned to find an example of a double permissive left, when there are countless examples in NYS, many being far less than a day's drive from all but the northern reaches of Maine. For the purposes of this thread, I would have absolutely grouped NYS with other states in that region.
That would be called "the Northeast", I suppose.
I usually don't get out of Northern New England a lot... I usually don't go farther than Boston or the South Shore in MA (outside of 128), west to Lowell/Nashua, and Portland and Rochester to the north. But you are correct that NYS from my part of Maine is less that a day's drive - about 5 to 10 hours depending on where you go to in NYS.
At least in my area and in New Hampshire, we don't associate NYS as part of New England but we do consider it part of the Northeast. The regions mrsman mentioned on reply no. 443 is how we view these regions though I'm not sure about DE as I have always put it on the mid-Atlantic segment for some time now.
Quote from: Amtrakprod on July 16, 2020, 05:28:10 PM
You'll be mocked pretty hard if you come to the real New England and say that NYS is part of it haha. They don't like us and we don't like them, the red sox rivalry didn't help.
You're sure right on that part! :sombrero: Even some of the locals in my city think NYS is a part of New England... :banghead:
Title: Re: Double left turns with permissive phasing
Post by: RestrictOnTheHanger on July 17, 2020, 10:15:27 PM
Post by: RestrictOnTheHanger on July 17, 2020, 10:15:27 PM
Quote from: US 89 on July 17, 2020, 01:43:03 AM
Just remembered a double permissive left I encountered in Parker, Colorado about a month ago. It caught me by surprise, as I don't routinely drive in areas with them.
https://goo.gl/maps/89js24aYYDRwa3sV8
I am not usually a fan of these, but if we're going to have them I'd say this type of environment is where they fit best: wide open suburban arterials with good sight lines.
I second the time of day variable phasing comment above. Navigating around shows that the older setup had doghouses over the left turn lanes, but with red arrows instead of red ball on top (for all directions). The FYAs were probably put in to comply with the MUTCD.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on July 19, 2020, 08:02:20 PM
Post by: mrsman on July 19, 2020, 08:02:20 PM
Quote from: RestrictOnTheHanger on July 17, 2020, 10:15:27 PMQuote from: US 89 on July 17, 2020, 01:43:03 AM
Just remembered a double permissive left I encountered in Parker, Colorado about a month ago. It caught me by surprise, as I don't routinely drive in areas with them.
https://goo.gl/maps/89js24aYYDRwa3sV8
I am not usually a fan of these, but if we're going to have them I'd say this type of environment is where they fit best: wide open suburban arterials with good sight lines.
I second the time of day variable phasing comment above. Navigating around shows that the older setup had doghouses over the left turn lanes, but with red arrows instead of red ball on top (for all directions). The FYAs were probably put in to comply with the MUTCD.
That's quite interesting. Do you know what the other indications of the doghouses were? I don't think I've ever seen a 5 aspect signal with a red arrow. What would each aspect be?
If I could surmise a guess, RA, YA, GA, YA , FYA. Two YA indications, one to terminate green arrow and one to terminate FYA. But I'm glad they changed to the more common 4 aspect FYA signals.
Title: Re: Double left turns with permissive phasing
Post by: US 89 on July 19, 2020, 10:11:45 PM
Post by: US 89 on July 19, 2020, 10:11:45 PM
Quote from: mrsman on July 19, 2020, 08:02:20 PMQuote from: RestrictOnTheHanger on July 17, 2020, 10:15:27 PMQuote from: US 89 on July 17, 2020, 01:43:03 AM
Just remembered a double permissive left I encountered in Parker, Colorado about a month ago. It caught me by surprise, as I don’t routinely drive in areas with them.
https://goo.gl/maps/89js24aYYDRwa3sV8
I am not usually a fan of these, but if we’re going to have them I’d say this type of environment is where they fit best: wide open suburban arterials with good sight lines.
I second the time of day variable phasing comment above. Navigating around shows that the older setup had doghouses over the left turn lanes, but with red arrows instead of red ball on top (for all directions). The FYAs were probably put in to comply with the MUTCD.
That's quite interesting. Do you know what the other indications of the doghouses were? I don't think I've ever seen a 5 aspect signal with a red arrow. What would each aspect be?
If I could surmise a guess, RA, YA, GA, YA , FYA. Two YA indications, one to terminate green arrow and one to terminate FYA. But I'm glad they changed to the more common 4 aspect FYA signals.
Looks like they were just regular doghouses, but with an arrow in the top instead of a light. Here's a GSV from 2018, before the FYAs went in (https://goo.gl/maps/N8ugyX6xKTjZs9gE8).
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 20, 2020, 12:43:43 AM
Post by: jakeroot on July 20, 2020, 12:43:43 AM
For the record, and I don't mean to sound arrogant: there is no need to point out any in Colorado.
Amongst all 50 states, Colorado seems to be the only one that not only allows double permissive left turns, but seems to encourage them. I have yet to find a major city in Colorado that didn't have at least one example, with many (such as Castle Rock, Arvada, Boulder, or Denver proper) having dozens (if not tens of dozens) of examples.
From what I've seen, quite a few do utilize TOD phasing. Colorado was a heavy user of the 'red-arrow in a doghouse' signal for decades. Although this is not to say that most operate this way. I would guess maybe 1 in 10 had this style of phasing.
Amongst all 50 states, Colorado seems to be the only one that not only allows double permissive left turns, but seems to encourage them. I have yet to find a major city in Colorado that didn't have at least one example, with many (such as Castle Rock, Arvada, Boulder, or Denver proper) having dozens (if not tens of dozens) of examples.
From what I've seen, quite a few do utilize TOD phasing. Colorado was a heavy user of the 'red-arrow in a doghouse' signal for decades. Although this is not to say that most operate this way. I would guess maybe 1 in 10 had this style of phasing.
Title: Re: Double left turns with permissive phasing
Post by: RestrictOnTheHanger on July 21, 2020, 04:42:19 PM
Post by: RestrictOnTheHanger on July 21, 2020, 04:42:19 PM
I never knew that type of doghouse was used before FYAs for TOD. These posts from different parts of the country are useful. Not everyone has been to/driven in every state nor knows generally what each jurisdiction does/not do.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on July 21, 2020, 07:32:09 PM
Post by: mrsman on July 21, 2020, 07:32:09 PM
Quote from: RestrictOnTheHanger on July 21, 2020, 04:42:19 PM
I never knew that type of doghouse was used before FYAs for TOD. These posts from different parts of the country are useful. Not everyone has been to/driven in every state nor knows generally what each jurisdiction does/not do.
I guess to a degree its kind of like Dallas phasing*. You focus on the signal that is in front of you. If you are in the left turn lane, your signal is the doghouse. Since the only people looking at the doghouse are turning left, a red arrow makes sense. But I think for this to work, the red arrow is only on when the adjacent signals have red orbs. (but not vice versa, you could have green arrow when adjacent signals have red orbs)
* But unlike Dallas phasing it doesn't seem to block the thru signals from view, so these should not be used for lagging lefts because of yellow trap issues.
Title: Re: Double left turns with permissive phasing
Post by: kphoger on July 22, 2020, 09:50:39 AM
Post by: kphoger on July 22, 2020, 09:50:39 AM
That's a lot of people who voted "Cat".
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 22, 2020, 01:42:08 PM
Post by: jakeroot on July 22, 2020, 01:42:08 PM
Quote from: mrsman on July 21, 2020, 07:32:09 PMQuote from: RestrictOnTheHanger on July 21, 2020, 04:42:19 PM
I never knew that type of doghouse was used before FYAs for TOD. These posts from different parts of the country are useful. Not everyone has been to/driven in every state nor knows generally what each jurisdiction does/not do.
I guess to a degree its kind of like Dallas phasing*. You focus on the signal that is in front of you. If you are in the left turn lane, your signal is the doghouse. Since the only people looking at the doghouse are turning left, a red arrow makes sense. But I think for this to work, the red arrow is only on when the adjacent signals have red orbs. (but not vice versa, you could have green arrow when adjacent signals have red orbs)
* But unlike Dallas phasing it doesn't seem to block the thru signals from view, so these should not be used for lagging lefts because of yellow trap issues.
Correct. The signals are quite like Dallas Phasing, apart from their inability to allow lagging green arrows. During the permissive time of day, they operate exactly like a regular doghouse: activated with adjacent green orb signals, with leading green arrows only. During the protected time of day, the arrows are the only signal faces utilized. There is the red arrow on the top, but this makes no difference to drivers apart from during the protected times of day, when it would be displayed when the adjacent traffic has a green orb displayed.
Honestly, the fact that this kind of display wasn't more common is surprising to me. As far as I know, before the advent of the FYA, it was the only way to allow permissive left turns based on time of day. For most jurisdictions, I suspect that TOD phasing wasn't really important for single left turns; that's fairly evident when you consider that ~99% of Colorado's red arrow doghouses are/were at double left turns, where TOD phasing may actually be important to reduce crashes. Based on this, I think we can assume that Colorado was also an early adopter of double permissive left turns, and one of the first to actually consider how time of day played into crash rates.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 22, 2020, 02:03:15 PM
Post by: jakeroot on July 22, 2020, 02:03:15 PM
Quote from: kphoger on July 22, 2020, 09:50:39 AM
That's a lot of people who voted "Cat".
Still kind of regret adding it as an option :-D. Only because there are 15 people who voted for neither "yes" or "no".
Quote from: RestrictOnTheHanger on July 21, 2020, 04:42:19 PM
I never knew that type of doghouse was used before FYAs for TOD. These posts from different parts of the country are useful. Not everyone has been to/driven in every state nor knows generally what each jurisdiction does/not do.
I don't know if this comment was directed at me. My comment around not mentioning those in Colorado is that, for those that are privy to the current double permissive left turn situation, it's already fairly well-known that Colorado has quite a lot of examples. I would have the same reaction if someone posted an example from Tucson; they're so unbelievably common in those jurisdictions, that it's simply not worth pointing out.
Normally, I would say "well, maybe they only saw one", to be a little fairer. But in places like Colorado or Tucson, they aren't really isolated. For example, considering US-89's example from Parker: I don't know how he got to Parker without seeing any others, nor how he left Parker without noticing any additional examples (be them FYA or doghouses). They are literally all over the Denver metro area, and there are multiple other examples in Parker itself (such as here (https://goo.gl/maps/obVbWeSo9gEGxquY6), here (https://goo.gl/maps/nhPzYsecDCNDbF3D9), or here (https://goo.gl/maps/ociamG7bvHDkoVzM6) -- I found these very quickly).
One exception: if your drive through Colorado was literally all freeway, I can see why you might only see one or two. Still, if you venture a couple miles off any freeway in a relatively suburban or urban area, you should see at least a couple examples.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 22, 2020, 02:15:31 PM
Post by: jakeroot on July 22, 2020, 02:15:31 PM
I think I've posted about this before: Japan has literally hundreds, perhaps thousands, of double permissive right turns (they drive on the left). Apart from a couple examples that I might have noted a while back, I haven't posted anymore. Today, I managed to find a triple permissive right turn in Osaka (link and image below).
This marks only the third triple permissive turn I've found (first two in South Africa here (https://goo.gl/maps/iybCT9m7AJ5xd4ny7) and here (https://goo.gl/maps/tj8mLkCQ9GYPK27k9) -- spin camera around to note signal state). Apart from maybe an isolated curb-to-curb turn, I suspect this is not something seen anywhere in North America, and is apparently only found in areas where permissive turns are normal for double lane turns (such as South Africa or Japan).
North end of Abeno Bridge, near the Abenobashi Terminal Building (https://www.google.com/maps/@34.6477741,135.5132102,91m/data=!3m1!1e3?hl=en) ---- Street View link (https://goo.gl/maps/jFwZtVxEAaA9LuaYA).
note the dotted markings indicating where to yield: there are three lanes leading to those dotted lines (outer lane is optional straight/right)...
(https://i.imgur.com/xZGzg70.png)
This marks only the third triple permissive turn I've found (first two in South Africa here (https://goo.gl/maps/iybCT9m7AJ5xd4ny7) and here (https://goo.gl/maps/tj8mLkCQ9GYPK27k9) -- spin camera around to note signal state). Apart from maybe an isolated curb-to-curb turn, I suspect this is not something seen anywhere in North America, and is apparently only found in areas where permissive turns are normal for double lane turns (such as South Africa or Japan).
North end of Abeno Bridge, near the Abenobashi Terminal Building (https://www.google.com/maps/@34.6477741,135.5132102,91m/data=!3m1!1e3?hl=en) ---- Street View link (https://goo.gl/maps/jFwZtVxEAaA9LuaYA).
note the dotted markings indicating where to yield: there are three lanes leading to those dotted lines (outer lane is optional straight/right)...
(https://i.imgur.com/xZGzg70.png)
Title: Re: Double left turns with permissive phasing
Post by: kphoger on July 22, 2020, 02:42:30 PM
Post by: kphoger on July 22, 2020, 02:42:30 PM
Quote from: jakeroot on July 22, 2020, 02:15:31 PM
I think I've posted about this before: Japan has literally hundreds, perhaps thousands, of double permissive right turns (they drive on the left). Apart from a couple examples that I might have noted a while back, I haven't posted anymore. Today, I managed to find a triple permissive right turn in Osaka (link and image below).
This marks only the third triple permissive turn I've found (first two in South Africa here (https://goo.gl/maps/iybCT9m7AJ5xd4ny7) and here (https://goo.gl/maps/tj8mLkCQ9GYPK27k9) -- spin camera around to note signal state). Apart from maybe an isolated curb-to-curb turn, I suspect this is not something seen anywhere in North America, and is apparently only found in areas where permissive turns are normal for double lane turns (such as South Africa or Japan).
North end of Abeno Bridge, near the Abenobashi Terminal Building (https://www.google.com/maps/@34.6477741,135.5132102,91m/data=!3m1!1e3?hl=en) ---- Street View link (https://goo.gl/maps/jFwZtVxEAaA9LuaYA).
note the dotted markings indicating where to yield: there are three lanes leading to those dotted lines (outer lane is optional straight/right)...
Here is GSV (https://goo.gl/maps/bA8i5Ayc3RuAvNZ67) of three vehicles waiting their turn.
And here is a relatively clear view (https://goo.gl/maps/9sFnMddQUdA7RgYw8) of the three lanes.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 22, 2020, 03:01:46 PM
Post by: jakeroot on July 22, 2020, 03:01:46 PM
Quote from: kphoger on July 22, 2020, 02:42:30 PMQuote from: jakeroot on July 22, 2020, 02:15:31 PM
I think I've posted about this before: Japan has literally hundreds, perhaps thousands, of double permissive right turns (they drive on the left). Apart from a couple examples that I might have noted a while back, I haven't posted anymore. Today, I managed to find a triple permissive right turn in Osaka (link and image below).
This marks only the third triple permissive turn I've found (first two in South Africa here (https://goo.gl/maps/iybCT9m7AJ5xd4ny7) and here (https://goo.gl/maps/tj8mLkCQ9GYPK27k9) -- spin camera around to note signal state). Apart from maybe an isolated curb-to-curb turn, I suspect this is not something seen anywhere in North America, and is apparently only found in areas where permissive turns are normal for double lane turns (such as South Africa or Japan).
North end of Abeno Bridge, near the Abenobashi Terminal Building (https://www.google.com/maps/@34.6477741,135.5132102,91m/data=!3m1!1e3?hl=en) ---- Street View link (https://goo.gl/maps/jFwZtVxEAaA9LuaYA).
note the dotted markings indicating where to yield: there are three lanes leading to those dotted lines (outer lane is optional straight/right)...
Here is GSV (https://goo.gl/maps/bA8i5Ayc3RuAvNZ67) of three vehicles waiting their turn.
And here is a relatively clear view (https://goo.gl/maps/9sFnMddQUdA7RgYw8) of the three lanes.
Not to crush you, but your first link is literally like 10 meters downwind from my Street View link (third paragraph) :-D
Funniest thing to me is how differently they are designed in Japan compared to other places like Tucson, where there is some fairly strict design guidelines for permissive turns across traffic. Japan basically says "go past this point and you'll hit other cars", but positive and negative offset is apparently not an issue (although this makes them more like Colorado, where there is no strict design guidelines).
I do really like Japan's propensity to use in-intersection yield lines. These make sense to me, and I don't know why they aren't used in the US. They are fairly common in other countries.
Title: Re: Double left turns with permissive phasing
Post by: stevashe on July 24, 2020, 05:22:37 PM
Post by: stevashe on July 24, 2020, 05:22:37 PM
Quote from: jakeroot on July 16, 2020, 03:17:52 PM
MN is a weird example, with tons of double-left FYA signals, but I don't know if they actually use the flashing phase.
I know of at least one FYA that does use the flashing phase, since I've seen it in person. I actually posted about it here before, but there wasn't streetview at the time, and I don't have a picture, but there is now: https://goo.gl/maps/NBTPF44iuPxGXmEFA. Unfortunately it only shows it with red arrows, but I assure you, it does flash! (The presence of the "Left Turn Yield on FYA" sign supports this as well.)
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 24, 2020, 07:22:33 PM
Post by: jakeroot on July 24, 2020, 07:22:33 PM
Quote from: stevashe on July 24, 2020, 05:22:37 PMQuote from: jakeroot on July 16, 2020, 03:17:52 PM
MN is a weird example, with tons of double-left FYA signals, but I don't know if they actually use the flashing phase.
I know of at least one FYA that does use the flashing phase, since I've seen it in person. I actually posted about it here before, but there wasn't streetview at the time, and I don't have a picture, but there is now: https://goo.gl/maps/NBTPF44iuPxGXmEFA. Unfortunately it only shows it with red arrows, but I assure you, it does flash! (The presence of the "Left Turn Yield on FYA" sign supports this as well.)
I believe you! Was it late at night?
Here's a GSV still that shows it with red arrows while the through traffic is green: https://goo.gl/maps/EmyGXW6G4hUXQDMR7
My understanding was that Minnesota was switching to all FYA displays, and operating them appropriately as needed. But that virtually all remained in protected-only mode, with just some operating with permissive phasing during off-peak (night-time only?) hours.
Title: Re: Double left turns with permissive phasing
Post by: kphoger on July 25, 2020, 10:46:48 AM
Post by: kphoger on July 25, 2020, 10:46:48 AM
Quote from: jakeroot on July 16, 2020, 03:17:52 PM
MN is a weird example, with tons of double-left FYA signals, but I don't know if they actually use the flashing phase.
Rogers Dr NB @ Diamond Lake Rd, Rogers, MN (https://goo.gl/maps/x5sFrwC7UqHjvTzZ9) – imagery from July 2019
(https://i.imgur.com/cuWttIV.png)
Title: Re: Double left turns with permissive phasing
Post by: mrsman on July 25, 2020, 11:03:59 PM
Post by: mrsman on July 25, 2020, 11:03:59 PM
Quote from: jakeroot on July 24, 2020, 07:22:33 PMQuote from: stevashe on July 24, 2020, 05:22:37 PMQuote from: jakeroot on July 16, 2020, 03:17:52 PM
MN is a weird example, with tons of double-left FYA signals, but I don't know if they actually use the flashing phase.
I know of at least one FYA that does use the flashing phase, since I've seen it in person. I actually posted about it here before, but there wasn't streetview at the time, and I don't have a picture, but there is now: https://goo.gl/maps/NBTPF44iuPxGXmEFA. Unfortunately it only shows it with red arrows, but I assure you, it does flash! (The presence of the "Left Turn Yield on FYA" sign supports this as well.)
I believe you! Was it late at night?
Here's a GSV still that shows it with red arrows while the through traffic is green: https://goo.gl/maps/EmyGXW6G4hUXQDMR7
My understanding was that Minnesota was switching to all FYA displays, and operating them appropriately as needed. But that virtually all remained in protected-only mode, with just some operating with permissive phasing during off-peak (night-time only?) hours.
It seems that the next intersection further south has a double left with FYA allowing a permissive left turn. The FYA is blank (which likely means that it occurred while the FYA was flashing and the camera captured it during the off mode). There is a car making a turn while cross traffic is coming.
https://www.google.com/maps/@44.8560521,-93.3631234,3a,73.1y,162.26h,78.98t/data=!3m6!1e1!3m4!1sAlbLLA0aAj1G90cLQ4x2gg!2e0!7i16384!8i8192?hl=en
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 26, 2020, 12:03:37 AM
Post by: jakeroot on July 26, 2020, 12:03:37 AM
^^^
Sweet, nice find. Both of you.
There's also this classic in Eden Prairie with an option lane: https://goo.gl/maps/KyCQYU8cimcm1VFv9
I think we can surmise, with great certainty, that most in the state do not operate with permissive phasing during daylight hours. I think the question is whether they are also disabled during night hours.
Sweet, nice find. Both of you.
There's also this classic in Eden Prairie with an option lane: https://goo.gl/maps/KyCQYU8cimcm1VFv9
I think we can surmise, with great certainty, that most in the state do not operate with permissive phasing during daylight hours. I think the question is whether they are also disabled during night hours.
Title: Re: Double left turns with permissive phasing
Post by: kphoger on July 28, 2020, 01:27:37 PM
Post by: kphoger on July 28, 2020, 01:27:37 PM
Quote from: mrsman on July 25, 2020, 11:03:59 PM
It seems that the next intersection further south has a double left with FYA allowing a permissive left turn. The FYA is blank (which likely means that it occurred while the FYA was flashing and the camera captured it during the off mode). There is a car making a turn while cross traffic is coming.
https://www.google.com/maps/@44.8560521,-93.3631234,3a,73.1y,162.26h,78.98t/data=!3m6!1e1!3m4!1sAlbLLA0aAj1G90cLQ4x2gg!2e0!7i16384!8i8192?hl=en
If you move back one step (https://goo.gl/maps/8U7MQkuG82HSKygSA), it's flashing yellow.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on July 31, 2020, 07:47:49 PM
Post by: Amtrakprod on July 31, 2020, 07:47:49 PM
Not permissive but close?
https://www.google.com/maps/@42.4793074,-71.1520325,3a,75y,59.72h,90.07t/data=!3m6!1e1!3m4!1stTjgz-pa2o1vgihJgokqWg!2e0!7i16384!8i8192
https://www.google.com/maps/@42.4793074,-71.1520325,3a,75y,59.72h,90.07t/data=!3m6!1e1!3m4!1stTjgz-pa2o1vgihJgokqWg!2e0!7i16384!8i8192
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 31, 2020, 11:49:54 PM
Post by: jakeroot on July 31, 2020, 11:49:54 PM
Quote from: Amtrakprod on July 31, 2020, 07:47:49 PM
Not permissive but close?
https://www.google.com/maps/@42.4793074,-71.1520325,3a,75y,59.72h,90.07t/data=!3m6!1e1!3m4!1stTjgz-pa2o1vgihJgokqWg!2e0!7i16384!8i8192
Close, but not really in the way that I'm looking for in this thread.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on October 10, 2020, 01:13:05 PM
Post by: jakeroot on October 10, 2020, 01:13:05 PM
I was going to avoid mentioning any that I found in Minnesota, given their propensity to use FYAs even when the plan is to use protected-only phasing, but I did find one today that was actually flashing:
Westbound Maryland Ave to southbound I-35E, St Paul (https://goo.gl/maps/BSE5bu5JaNx4Z8GX8)
Have I been mistaken in assuming that, despite the double FYA being hilariously common in MN, that they almost never use permissive phasing? Or is it more common than I realize in certain conditions (on-ramp left turns, late at night, etc).
Westbound Maryland Ave to southbound I-35E, St Paul (https://goo.gl/maps/BSE5bu5JaNx4Z8GX8)
Have I been mistaken in assuming that, despite the double FYA being hilariously common in MN, that they almost never use permissive phasing? Or is it more common than I realize in certain conditions (on-ramp left turns, late at night, etc).
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on October 10, 2020, 09:01:52 PM
Post by: jakeroot on October 10, 2020, 09:01:52 PM
Finally found an example in Hawaii:
Southbound Victoria Street @ King St (https://goo.gl/maps/ywBQdnijLPAZRWUNA); Honolulu (spin camera to see opposing signal state)
I find it odd that the solid line directs the outer left turn lane into the farther lanes, ostensibly the area where the opposing right turn would turn into it. All despite King St being 5 or 6 lanes eastbound.
Southbound Victoria Street @ King St (https://goo.gl/maps/ywBQdnijLPAZRWUNA); Honolulu (spin camera to see opposing signal state)
I find it odd that the solid line directs the outer left turn lane into the farther lanes, ostensibly the area where the opposing right turn would turn into it. All despite King St being 5 or 6 lanes eastbound.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on October 29, 2020, 08:56:22 PM
Post by: Amtrakprod on October 29, 2020, 08:56:22 PM
In NYC: https://www.google.com/maps/@40.7163818,-73.9959115,3a,46.2y,233.81h,89.73t/data=!3m6!1e1!3m4!1sOyPlYT-kTl0ph4T1-JRifw!2e0!7i16384!8i8192
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on October 30, 2020, 12:29:40 AM
Post by: jakeroot on October 30, 2020, 12:29:40 AM
Quote from: Amtrakprod on October 29, 2020, 08:56:22 PM
In NYC: https://www.google.com/maps/@40.7163818,-73.9959115,3a,46.2y,233.81h,89.73t/data=!3m6!1e1!3m4!1sOyPlYT-kTl0ph4T1-JRifw!2e0!7i16384!8i8192
An interesting case of "we need two lanes for both movements, but there's no way to fit split phasing into this intersection". So they just option the center lane and keep it protected/permissive. Very nice, NYCDOT.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on November 01, 2020, 02:14:08 PM
Post by: mrsman on November 01, 2020, 02:14:08 PM
Quote from: jakeroot on October 30, 2020, 12:29:40 AMQuote from: Amtrakprod on October 29, 2020, 08:56:22 PM
In NYC: https://www.google.com/maps/@40.7163818,-73.9959115,3a,46.2y,233.81h,89.73t/data=!3m6!1e1!3m4!1sOyPlYT-kTl0ph4T1-JRifw!2e0!7i16384!8i8192
An interesting case of "we need two lanes for both movements, but there's no way to fit split phasing into this intersection". So they just option the center lane and keep it protected/permissive. Very nice, NYCDOT.
This occurs in a few places in NYC for exactly the reasons you state. Generally, these involve a lagging left and opposing left being prohibited, so that someone stuck behind a car going left in the option lane can be assured that they will have the opportunity to go at the end of the cycle. Prohibiting the opposing left avoids a yellow trap problem that would otherwise be caused with the lagging left.
As this is right near the entrance to the Manhattan bridge, and a busy area, it is very rare that someone would be able to make the permitted turn, so effectively the turns only occur during the protected phase. But theoretically, yes, turns are permitted on green orb when yielding to opposing traffic.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on November 01, 2020, 03:43:13 PM
Post by: jakeroot on November 01, 2020, 03:43:13 PM
Quote from: mrsman on November 01, 2020, 02:14:08 PMQuote from: jakeroot on October 30, 2020, 12:29:40 AMQuote from: Amtrakprod on October 29, 2020, 08:56:22 PM
In NYC: https://www.google.com/maps/@40.7163818,-73.9959115,3a,46.2y,233.81h,89.73t/data=!3m6!1e1!3m4!1sOyPlYT-kTl0ph4T1-JRifw!2e0!7i16384!8i8192
An interesting case of "we need two lanes for both movements, but there's no way to fit split phasing into this intersection". So they just option the center lane and keep it protected/permissive. Very nice, NYCDOT.
This occurs in a few places in NYC for exactly the reasons you state. Generally, these involve a lagging left and opposing left being prohibited, so that someone stuck behind a car going left in the option lane can be assured that they will have the opportunity to go at the end of the cycle. Prohibiting the opposing left avoids a yellow trap problem that would otherwise be caused with the lagging left.
As this is right near the entrance to the Manhattan bridge, and a busy area, it is very rare that someone would be able to make the permitted turn, so effectively the turns only occur during the protected phase. But theoretically, yes, turns are permitted on green orb when yielding to opposing traffic.
It's kind of crazy to me to think that it was only a single lane left turn before. I would have to assume that this isn't the primary entrance to the Manhattan Bridge.
Anyone in the area care to comment how split the center lane is in terms of whether it's primarily used by left turns or through traffic?
Title: Re: Double left turns with permissive phasing
Post by: mrsman on November 03, 2020, 01:14:43 PM
Post by: mrsman on November 03, 2020, 01:14:43 PM
Quote from: jakeroot on November 01, 2020, 03:43:13 PMQuote from: mrsman on November 01, 2020, 02:14:08 PMQuote from: jakeroot on October 30, 2020, 12:29:40 AMQuote from: Amtrakprod on October 29, 2020, 08:56:22 PM
In NYC: https://www.google.com/maps/@40.7163818,-73.9959115,3a,46.2y,233.81h,89.73t/data=!3m6!1e1!3m4!1sOyPlYT-kTl0ph4T1-JRifw!2e0!7i16384!8i8192
An interesting case of "we need two lanes for both movements, but there's no way to fit split phasing into this intersection". So they just option the center lane and keep it protected/permissive. Very nice, NYCDOT.
This occurs in a few places in NYC for exactly the reasons you state. Generally, these involve a lagging left and opposing left being prohibited, so that someone stuck behind a car going left in the option lane can be assured that they will have the opportunity to go at the end of the cycle. Prohibiting the opposing left avoids a yellow trap problem that would otherwise be caused with the lagging left.
As this is right near the entrance to the Manhattan bridge, and a busy area, it is very rare that someone would be able to make the permitted turn, so effectively the turns only occur during the protected phase. But theoretically, yes, turns are permitted on green orb when yielding to opposing traffic.
It's kind of crazy to me to think that it was only a single lane left turn before. I would have to assume that this isn't the primary entrance to the Manhattan Bridge.
Anyone in the area care to comment how split the center lane is in terms of whether it's primarily used by left turns or through traffic?
From my experience, it seems like most people in the middle lane go to the bridge, instead of continuing down Bowery. An exception may be during the morning hours as more traffic is likely headed toward Downtown and not to Brooklyn.
Fewer people may be headed south on Bowery, given the closure of Park Row near police headquarters since 9/11. Perhaps it was this closure that caused more traffic headed Downtown to use FDR or Broadway, while having more people using the bridge take Bowery. Bowery is still not the main flow of traffic into the bridge, far more of the traffic is headed from the western side of the area and taking Canal, especially traffic from the Holland Tunnel.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on November 03, 2020, 02:47:54 PM
Post by: jakeroot on November 03, 2020, 02:47:54 PM
Quote from: mrsman on November 03, 2020, 01:14:43 PM
From my experience, it seems like most people in the middle lane go to the bridge, instead of continuing down Bowery. An exception may be during the morning hours as more traffic is likely headed toward Downtown and not to Brooklyn.
This seems like an important point, and where option-lane setups can actually be quite ideal. The flow of traffic not necessarily even throughout the day, so allowing traffic to determine the dominant movement of the center lane based on time of day allows a great deal of flexibility without the added cost (and likely conversion to protected-only phasing) of a double left + double through setup.
The only real issues right now, if I had to guess, would be (A) traffic cops making the overall setup and phasing totally redundant (unless they are there to preserve order and let the signals do the work...I don't know how NYC operates in this regard); (B) the potential for pedestrian collisions (reduced by the presence of the police in A); and (C) the potential for rear-end crashes if someone in the morning hours turns left from the middle lane, and gets hit from the rear by a car used to center lane traffic continuing south along Bowery. For B and C, I think NYC drivers are well-enough versed in avoiding these situations that neither are likely major issues.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on November 03, 2020, 11:24:46 PM
Post by: jakeroot on November 03, 2020, 11:24:46 PM
Found another in California. Suburban Pleasanton, totally surrounded by protected signals as is the norm in Northern California:
https://goo.gl/maps/oyKJ8JF5sfP9JPJq9
The center lane is an optional left/straight lane.
https://goo.gl/maps/oyKJ8JF5sfP9JPJq9
The center lane is an optional left/straight lane.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on November 04, 2020, 11:50:51 AM
Post by: mrsman on November 04, 2020, 11:50:51 AM
Quote from: jakeroot on November 03, 2020, 11:24:46 PM
Found another in California. Suburban Pleasanton, totally surrounded by protected signals as is the norm in Northern California:
https://goo.gl/maps/oyKJ8JF5sfP9JPJq9
The center lane is an optional left/straight lane.
Good application of double permissive here. Even in states that are generally concerned about allowing double permissive, which CA generally is, there is a realization that where the opposing traffic comes from a really low traffic street, especially a residential one without an outlet and only a handful of houses, there is no problem in allowing the permissive turn - as is generally the case if this were a T intersection. From this view of the intersection, you can see that on a green light, there is no traffic coming from the residential street at all and that is likely the case for a large part of the day.
https://www.google.com/maps/@37.6944605,-121.8781282,3a,75y,332.9h,82.29t/data=!3m6!1e1!3m4!1snpZHTke1Oglrxh9qE_RFzA!2e0!7i13312!8i6656
Title: Re: Double left turns with permissive phasing
Post by: mrsman on November 04, 2020, 12:05:29 PM
Post by: mrsman on November 04, 2020, 12:05:29 PM
Quote from: jakeroot on November 03, 2020, 02:47:54 PMQuote from: mrsman on November 03, 2020, 01:14:43 PM
From my experience, it seems like most people in the middle lane go to the bridge, instead of continuing down Bowery. An exception may be during the morning hours as more traffic is likely headed toward Downtown and not to Brooklyn.
This seems like an important point, and where option-lane setups can actually be quite ideal. The flow of traffic not necessarily even throughout the day, so allowing traffic to determine the dominant movement of the center lane based on time of day allows a great deal of flexibility without the added cost (and likely conversion to protected-only phasing) of a double left + double through setup.
The only real issues right now, if I had to guess, would be (A) traffic cops making the overall setup and phasing totally redundant (unless they are there to preserve order and let the signals do the work...I don't know how NYC operates in this regard); (B) the potential for pedestrian collisions (reduced by the presence of the police in A); and (C) the potential for rear-end crashes if someone in the morning hours turns left from the middle lane, and gets hit from the rear by a car used to center lane traffic continuing south along Bowery. For B and C, I think NYC drivers are well-enough versed in avoiding these situations that neither are likely major issues.
Another thing to also keep in mind for NYC (and many other cities as well) which has a big problem of illegal parking and double parking. Converting the street to 4 SB lanes: 2 left onto the bridge and 2 continuing southbound can only be done cheaply by prohibiting parking for about half a block north of the Bowery/Canal intersection. [I assume that widening the street by narrowing the sidewalk is not feasible at all.] But given the rampant parking issues, the right thru lane, being against the curb, would be constantly blocked under the 2 left and 2 SB setup. So to achieve 2 lanes south with 2 lanes left, and maintain a regular parking lane on both sides of the street, having 3 SB lanes with the middle lane serve as an optional straight/left is the only way to do it, and that's what they did.
Title: Re: Double left turns with permissive phasing
Post by: NoGoodNamesAvailable on November 04, 2020, 10:37:27 PM
Post by: NoGoodNamesAvailable on November 04, 2020, 10:37:27 PM
At I-280 and Northfield Avenue in West Orange, NJ (https://goo.gl/maps/HAgtm8CymwzpiwcCA)
Not sure if this was posted yet. I am pleasantly surprised that they did not split-phase this intersection. There's also a jughandle for left turns onto Wheeler Ave, so in a lot of other states this two-phase intersection would probably have four phases. Sometimes left turning traffic coming off the ramp may not realize that they need to yield to oncoming right turns (NJ's habit of only using green balls for split-phase intersections does not help with this), but since Wheeler Street is pretty minor, drivers are usually slow and cautious and there is rarely an issue.
Not sure if this was posted yet. I am pleasantly surprised that they did not split-phase this intersection. There's also a jughandle for left turns onto Wheeler Ave, so in a lot of other states this two-phase intersection would probably have four phases. Sometimes left turning traffic coming off the ramp may not realize that they need to yield to oncoming right turns (NJ's habit of only using green balls for split-phase intersections does not help with this), but since Wheeler Street is pretty minor, drivers are usually slow and cautious and there is rarely an issue.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on November 04, 2020, 10:46:23 PM
Post by: jakeroot on November 04, 2020, 10:46:23 PM
Quote from: NoGoodNamesAvailable on November 04, 2020, 10:37:27 PM
At I-280 and Northfield Avenue in West Orange, NJ (https://goo.gl/maps/HAgtm8CymwzpiwcCA)
Not sure if this was posted yet. I am pleasantly surprised that they did not split-phase this intersection. There's also a jughandle for left turns onto Wheeler Ave, so in a lot of other states this two-phase intersection would probably have four phases. Sometimes left turning traffic coming off the ramp may not realize that they need to yield to oncoming right turns (NJ's habit of only using green balls for split-phase intersections does not help with this), but since Wheeler Street is pretty minor, drivers are usually slow and cautious and there is rarely an issue.
Not yet posted that I know of.
This reminds me a lot of the one above from Pleasanton, Calif: what I assume is a very busy street meeting what I assume is a very quiet street (as it was pointed out by mrsman). There is no reason to use split-phasing here because that added level of protection would so rarely ever be necessary, and the extra phase would occasionally throw a wrench into the intersection timing. Plus I'm sure drivers would grow tired of waiting for that approach to activate. I'm sure, in many cases, drivers would just barely miss that window of activation and would be kept waiting far longer than necessary.
I do think the intersection could use "yield on green" signs like the one in California, so that drivers are at least aware of the oncoming traffic having precedence over their left turn. Especially if all-green-orb split phased intersections are as common in NJ as you say.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on November 05, 2020, 07:43:47 AM
Post by: mrsman on November 05, 2020, 07:43:47 AM
Quote from: jakeroot on November 04, 2020, 10:46:23 PMQuote from: NoGoodNamesAvailable on November 04, 2020, 10:37:27 PM
At I-280 and Northfield Avenue in West Orange, NJ (https://goo.gl/maps/HAgtm8CymwzpiwcCA)
Not sure if this was posted yet. I am pleasantly surprised that they did not split-phase this intersection. There's also a jughandle for left turns onto Wheeler Ave, so in a lot of other states this two-phase intersection would probably have four phases. Sometimes left turning traffic coming off the ramp may not realize that they need to yield to oncoming right turns (NJ's habit of only using green balls for split-phase intersections does not help with this), but since Wheeler Street is pretty minor, drivers are usually slow and cautious and there is rarely an issue.
Not yet posted that I know of.
This reminds me a lot of the one above from Pleasanton, Calif: what I assume is a very busy street meeting what I assume is a very quiet street (as it was pointed out by mrsman). There is no reason to use split-phasing here because that added level of protection would so rarely ever be necessary, and the extra phase would occasionally throw a wrench into the intersection timing. Plus I'm sure drivers would grow tired of waiting for that approach to activate. I'm sure, in many cases, drivers would just barely miss that window of activation and would be kept waiting far longer than necessary.
I do think the intersection could use "yield on green" signs like the one in California, so that drivers are at least aware of the oncoming traffic having precedence over their left turn. Especially if all-green-orb split phased intersections are as common in NJ as you say.
This seems to be a bit of a special circumstance. The two left turn lanes here do need to yield, but because the street is one-way there is no opposing thru traffic here - only right tunting traffic from Wheeler. That being said, there probably aren't too many like it, because most of the time this type of configuration (heavy one-way, especially a freeway exit, opposing a light residential street) is almost always signalled as split-phase if there are multiple lefts allowed. But given Wheeler is lightly traveled, the only thing I would add is a "left turn yield on green" as the current signalization seems adequate.
Title: Re: Double left turns with permissive phasing
Post by: jeffandnicole on November 05, 2020, 09:18:37 AM
Post by: jeffandnicole on November 05, 2020, 09:18:37 AM
Quote from: jakeroot on November 03, 2020, 02:47:54 PM
The only real issues right now, if I had to guess, would be (A) traffic cops making the overall setup and phasing totally redundant (unless they are there to preserve order and let the signals do the work...I don't know how NYC operates in this regard);
Basically, this. In my experiences and observations, there are a lot of cops on duty at any one time, and unlike what some people think, they can't be all investigating crimes. They need cops on the street available for incidents. But when everything is running ok, the cops are placed at intersections just to monitor and assist as needed. In the GSV link, you see the road is closed, a few cars in the dedicated left turn lane, and the cop, as you pan downstream, appears to either be trying to wave the leading vehicle to go straight or talking to him.
The cops will also help control traffic when needed. Take for example a common one-way to one-way left turn. Hard to make that left turn when pedestrians are non-stop crossing the road. The cop, when the light turns yellow, will take a step (literally, a step), and wave some of that left turning traffic thru the end of the yellow and beginning of the red, just before the opposing direction gets the green and their walk signal. It gets a few of the lagging left turners thru, and with the cop there, keeps things under control. If you have a hotel room above the street where you can watch some of this overhead, it's fairly interesting how they do it, without it turning into a free-for-all.
A few years back, I happened to be staying near the PANYNJ Bus Terminal when a terrorist tried to set off a bomb, and was unsuccessful. Those cops on the street were instantly able to pull out the metal crowd control barriers that NYPD have placed near each intersection, blocking pedestrians and motorists from getting close, and rerouting traffic away from the incident. Once the incident was quickly determined to be a lone attempt, unsuccessful and the threat subsided, the officers allowed pedestrians thru, and when given the all clear, moved the barriers to allow traffic thru. The speed at which all of this occurs is mind-boggling for such a large city, but shows why NYC chose to keep cops at many intersection.
Quote from: jakeroot on November 03, 2020, 02:47:54 PM
(B) the potential for pedestrian collisions (reduced by the presence of the police in A); and (C) the potential for rear-end crashes if someone in the morning hours turns left from the middle lane, and gets hit from the rear by a car used to center lane traffic continuing south along Bowery. For B and C, I think NYC drivers are well-enough versed in avoiding these situations that neither are likely major issues.
Oh, yeah, this is so typical of NYC Driving. And if someone were to be bumped, they at most would get out, look at it, maybe quickly get each other's info, and take off.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on November 07, 2020, 04:55:31 PM
Post by: jakeroot on November 07, 2020, 04:55:31 PM
Found one on PEI. Now removed with the construction of a displaced left turn.
Charlottetown, PEI: Southbound St Peters Rd @ Riverside (TCH) (https://goo.gl/maps/7H8hpw2vZB5GbW6A8).
No idea how common these are in PEI, if at all.
Edit: another across the harbour:
Charlottetown, PEI: Northbound Stratford Rd @ the TCH (https://goo.gl/maps/7fkXbk4DQdS2jv938).
Charlottetown, PEI: Southbound St Peters Rd @ Riverside (TCH) (https://goo.gl/maps/7H8hpw2vZB5GbW6A8).
No idea how common these are in PEI, if at all.
Edit: another across the harbour:
Charlottetown, PEI: Northbound Stratford Rd @ the TCH (https://goo.gl/maps/7fkXbk4DQdS2jv938).
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on November 18, 2020, 12:53:03 AM
Post by: jakeroot on November 18, 2020, 12:53:03 AM
Just posted over in the 'double doghouse' thread by Revive 755. I don't believe this has been posted yet. St Louis, MO:
Quote from: Revive 755 on November 17, 2020, 11:02:48 PM
NB Skinker Boulevard at Forest Park Parkway in St. Louis, MO has a double doghouse for a protected-permissive dual left. (https://goo.gl/maps/RGTsnKGNNdfUiKvq8)
Title: Re: Double left turns with permissive phasing
Post by: RestrictOnTheHanger on November 20, 2020, 11:34:04 PM
Post by: RestrictOnTheHanger on November 20, 2020, 11:34:04 PM
Saw this example in MN via a youtube livestream just now. Based on the GSV taken in daylight it looks like this uses time of day phasing. On the livestream the FYA was in permissive mode
https://maps.app.goo.gl/DVGm9Sqx1hVk5RKJ8
https://maps.app.goo.gl/DVGm9Sqx1hVk5RKJ8
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on November 21, 2020, 10:29:27 AM
Post by: Amtrakprod on November 21, 2020, 10:29:27 AM
Quote from: RestrictOnTheHanger on November 20, 2020, 11:34:04 PMCould you link that live?
Saw this example in MN via a youtube livestream just now. Based on the GSV taken in daylight it looks like this uses time of day phasing. On the livestream the FYA was in permissive mode
https://maps.app.goo.gl/DVGm9Sqx1hVk5RKJ8
iPhone
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on November 21, 2020, 07:23:37 PM
Post by: jakeroot on November 21, 2020, 07:23:37 PM
It seems that Minnesota has wholly adopted the double left flashing yellow arrow + TOD phasing protocol. How often are double protected only signals still installed around there? Seems like FYAs are the de-facto choice. Apart from maybe a triple left turn.
Title: Re: Double left turns with permissive phasing
Post by: RestrictOnTheHanger on November 22, 2020, 12:28:20 AM
Post by: RestrictOnTheHanger on November 22, 2020, 12:28:20 AM
Quote from: Amtrakprod on November 21, 2020, 10:29:27 AMQuote from: RestrictOnTheHanger on November 20, 2020, 11:34:04 PMCould you link that live?
Saw this example in MN via a youtube livestream just now. Based on the GSV taken in daylight it looks like this uses time of day phasing. On the livestream the FYA was in permissive mode
https://maps.app.goo.gl/DVGm9Sqx1hVk5RKJ8
iPhone
https://youtu.be/sJyzGvwkNX4
Skip to 1:11:11 (1h 11m 11s)
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on November 22, 2020, 06:57:48 PM
Post by: jakeroot on November 22, 2020, 06:57:48 PM
Thank you for the link. Pretty nice to see one of these MN examples actually going.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on November 23, 2020, 05:24:35 PM
Post by: Amtrakprod on November 23, 2020, 05:24:35 PM
Nice. I like that Minnesota used TOD for those signals. Minnesota had my favorite uses of flashing yellow arrow signals (besides the flashing yellow bike even though I get the point).
iPhone
iPhone
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on November 26, 2020, 12:04:59 AM
Post by: fwydriver405 on November 26, 2020, 12:04:59 AM
Found this (https://www.google.com/maps/@40.5921464,-105.077672,3a,26.3y,85.5h,88.7t/data=!3m6!1e1!3m4!1shHNrWO6loq_rzeZm3g5ApA!2e0!7i16384!8i8192) one in Fort Collins CO. This one has RR tracks that bisect this intersection...
Title: Re: Double left turns with permissive phasing
Post by: roadfro on November 26, 2020, 03:05:12 PM
Post by: roadfro on November 26, 2020, 03:05:12 PM
Quote from: fwydriver405 on November 26, 2020, 12:04:59 AM
Found this (https://www.google.com/maps/@40.5921464,-105.077672,3a,26.3y,85.5h,88.7t/data=!3m6!1e1!3m4!1shHNrWO6loq_rzeZm3g5ApA!2e0!7i16384!8i8192) one in Fort Collins CO. This one has RR tracks that bisect this intersection...
Green signals for the railroad immediately in front of red signals for the intersection?! Oh, that's messy...
They should have implemented an overlap between the railroad signal and the traffic signal to cut down on the mixed signals displayed here (pun intended) Or, you know, use regular railroad crossing lights & gates.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on November 26, 2020, 08:33:12 PM
Post by: mrsman on November 26, 2020, 08:33:12 PM
Quote from: roadfro on November 26, 2020, 03:05:12 PMQuote from: fwydriver405 on November 26, 2020, 12:04:59 AM
Found this (https://www.google.com/maps/@40.5921464,-105.077672,3a,26.3y,85.5h,88.7t/data=!3m6!1e1!3m4!1shHNrWO6loq_rzeZm3g5ApA!2e0!7i16384!8i8192) one in Fort Collins CO. This one has RR tracks that bisect this intersection...
Green signals for the railroad immediately in front of red signals for the intersection?! Oh, that's messy...
They should have implemented an overlap between the railroad signal and the traffic signal to cut down on the mixed signals displayed here (pun intended) Or, you know, use regular railroad crossing lights & gates.
It's also weird that the trains themselves seem to be controlled by a regular traffic light. This generally only occurs on streetcars or light rail, not heavy rail corridors. Does anyone know what types of trains run on these tracks?
Title: Re: Double left turns with permissive phasing
Post by: US 89 on November 27, 2020, 01:47:04 AM
Post by: US 89 on November 27, 2020, 01:47:04 AM
Quote from: mrsman on November 26, 2020, 08:33:12 PM
It's also weird that the trains themselves seem to be controlled by a regular traffic light. This generally only occurs on streetcars or light rail, not heavy rail corridors. Does anyone know what types of trains run on these tracks?
This is rare but I've seen it on some low traffic industrial freight spurs - here's an example I know of in western Salt Lake City. (https://goo.gl/maps/YCoKT1XbRMkPtmRm6)
Title: Re: Double left turns with permissive phasing
Post by: Dirt Roads on November 27, 2020, 09:53:45 AM
Post by: Dirt Roads on November 27, 2020, 09:53:45 AM
Quote from: mrsman on November 26, 2020, 08:33:12 PM
It's also weird that the trains themselves seem to be controlled by a regular traffic light. This generally only occurs on streetcars or light rail, not heavy rail corridors. Does anyone know what types of trains run on these tracks?
Quote from: US 89 on November 27, 2020, 01:47:04 AM
This is rare but I've seen it on some low traffic industrial freight spurs - here's an example I know of in western Salt Lake City. (https://goo.gl/maps/YCoKT1XbRMkPtmRm6)
This one in SLC looks like a road atop the industrial spur [tracks]. In more intense shipping settings, imbedded tracks (in this usage, rails imbedded in industrial roadways and shipping yards) are fairly common, but this pix looks like a smaller industry that has appropriately their rail spur as an outlet to gain access to a signalized intersection. Almost always, longer industrial spurs are privately maintained. It ain't cheap to maintain imbedded tracks, so I hope they knew what they were getting into when they paved over the spur.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on November 27, 2020, 10:29:00 AM
Post by: fwydriver405 on November 27, 2020, 10:29:00 AM
Quote from: US 89 on November 27, 2020, 01:47:04 AMQuote from: mrsman on November 26, 2020, 08:33:12 PM
It's also weird that the trains themselves seem to be controlled by a regular traffic light. This generally only occurs on streetcars or light rail, not heavy rail corridors. Does anyone know what types of trains run on these tracks?
This is rare but I've seen it on some low traffic industrial freight spurs - here's an example I know of in western Salt Lake City. (https://goo.gl/maps/YCoKT1XbRMkPtmRm6)
I remember watching a video of such a crossing like that in Ohio. Mason, Ohio at US 42 and Tylersville Rd (https://www.google.com/maps/place/US-42+%26+Tylersville+Rd,+Mason,+OH+45040,+USA/@39.3518976,-84.3223125,17z/data=!4m5!3m4!1s0x884059d76bc3ddd5:0x3043dd62d088a792!8m2!3d39.3518976!4d-84.3214327).
Title: Re: Double left turns with permissive phasing
Post by: Dirt Roads on November 27, 2020, 11:35:40 AM
Post by: Dirt Roads on November 27, 2020, 11:35:40 AM
Quote from: mrsman on November 26, 2020, 08:33:12 PM
It's also weird that the trains themselves seem to be controlled by a regular traffic light. This generally only occurs on streetcars or light rail, not heavy rail corridors. Does anyone know what types of trains run on these tracks?
Quote from: US 89 on November 27, 2020, 01:47:04 AM
This is rare but I've seen it on some low traffic industrial freight spurs - here's an example I know of in western Salt Lake City. (https://goo.gl/maps/YCoKT1XbRMkPtmRm6)
Quote from: fwydriver405 on November 27, 2020, 10:29:00 AM
I remember watching a video of such a crossing like that in Ohio. Mason, Ohio at US 42 and Tylersville Rd (https://www.google.com/maps/place/US-42+%26+Tylersville+Rd,+Mason,+OH+45040,+USA/@39.3518976,-84.3223125,17z/data=!4m5!3m4!1s0x884059d76bc3ddd5:0x3043dd62d088a792!8m2!3d39.3518976!4d-84.3214327).
This type of train operation (traffic signals at exempt crossings) is not so uncommon, but the railroad-only traffic signal added to the intersection is very rare. For those who didn't watch carefully, the brakeman walked over to the traffic signal and keyed up the crossing preempt for the traffic signal. Before the advent of crossing predictors (train detection circuits that predict the arrival time based on train speed), this key-up was very common at most urban grade crossings. Exempt crossings require the train crew to flag the crossing before entering the street.
Back to the main topic, this type of train operation (signal key-up) is most certainly used at the double left turn crossing example in western SLC as well.
Title: Re: Double left turns with permissive phasing
Post by: Dirt Roads on November 27, 2020, 11:59:37 AM
Post by: Dirt Roads on November 27, 2020, 11:59:37 AM
Quote from: mrsman on November 26, 2020, 08:33:12 PM
It's also weird that the trains themselves seem to be controlled by a regular traffic light. This generally only occurs on streetcars or light rail, not heavy rail corridors. Does anyone know what types of trains run on these tracks?
Quote from: US 89 on November 27, 2020, 01:47:04 AM
This is rare but I've seen it on some low traffic industrial freight spurs - here's an example I know of in western Salt Lake City. (https://goo.gl/maps/YCoKT1XbRMkPtmRm6)
Quote from: fwydriver405 on November 27, 2020, 10:29:00 AM
I remember watching a video of such a crossing like that in Ohio. Mason, Ohio at US 42 and Tylersville Rd (https://www.google.com/maps/place/US-42+%26+Tylersville+Rd,+Mason,+OH+45040,+USA/@39.3518976,-84.3223125,17z/data=!4m5!3m4!1s0x884059d76bc3ddd5:0x3043dd62d088a792!8m2!3d39.3518976!4d-84.3214327).
Quote from: Dirt Roads on November 27, 2020, 11:35:40 AM
This type of train operation (traffic signals at exempt crossings) is not so uncommon, but the railroad-only traffic signal added to the intersection is very rare. For those who didn't watch carefully, the brakeman walked over to the traffic signal and keyed up the crossing preempt for the traffic signal. Before the advent of crossing predictors (train detection circuits that predict the arrival time based on train speed), this key-up was very common at most urban grade crossings. Exempt crossings require the train crew to flag the crossing before entering the street.
Back to the main topic, this type of train operation (signal key-up) is most certainly used at the double left turn crossing example in western SLC as well.
Oh, and the EXEMPT plaque (R15‑3P or W10‑1aP) is unique to the MUTCD as it is a courtesy to hazmat trucks and school buses that are otherwise required to stop at the crossing. Since many of these crossings are private and not maintained by the railroad, it is difficult to get these EXEMPT plaques maintained properly (note that most private crossing are contracted for maintenance to the railroad, which should keep them maintained).
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on December 06, 2020, 08:32:55 PM
Post by: fwydriver405 on December 06, 2020, 08:32:55 PM
Would this (https://www.google.com/maps/@40.7291022,-74.0105656,3a,89.3y,264.34h,85.22t/data=!3m6!1e1!3m4!1syEy9tAJvkerMyHTirZWegg!2e0!7i16384!8i8192) intersection in New York City count as such? Direction from W Houston St has Left and Left+Thru setup. Looks like the only thing the double left has to yield to is the opposing right turn.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on December 08, 2020, 01:20:06 PM
Post by: mrsman on December 08, 2020, 01:20:06 PM
Quote from: fwydriver405 on December 06, 2020, 08:32:55 PM
Would this (https://www.google.com/maps/@40.7291022,-74.0105656,3a,89.3y,264.34h,85.22t/data=!3m6!1e1!3m4!1syEy9tAJvkerMyHTirZWegg!2e0!7i16384!8i8192) intersection in New York City count as such? Direction from W Houston St has Left and Left+Thru setup. Looks like the only thing the double left has to yield to is the opposing right turn.
Hard to say. There is definitely the need to yield to the opposing right turn, but this is different from standard because the street with the double left is one-way. I think that its fine to note this one, because the usual signalization for a similar setup would be split-phasing, but this clearly has EB and WB traffic at the same time.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on December 08, 2020, 03:40:07 PM
Post by: jakeroot on December 08, 2020, 03:40:07 PM
Quote from: mrsman on December 08, 2020, 01:20:06 PMQuote from: fwydriver405 on December 06, 2020, 08:32:55 PM
Would this (https://www.google.com/maps/@40.7291022,-74.0105656,3a,89.3y,264.34h,85.22t/data=!3m6!1e1!3m4!1syEy9tAJvkerMyHTirZWegg!2e0!7i16384!8i8192) intersection in New York City count as such? Direction from W Houston St has Left and Left+Thru setup. Looks like the only thing the double left has to yield to is the opposing right turn.
Hard to say. There is definitely the need to yield to the opposing right turn, but this is different from standard because the street with the double left is one-way. I think that its fine to note this one, because the usual signalization for a similar setup would be split-phasing, but this clearly has EB and WB traffic at the same time.
I agree, it's not perfect in terms of being like examples from Colorado or Tucson, but it's still an example I would include in this thread. I have posted examples identical to this from both Hawaii and Seattle (basically identical).
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on January 20, 2021, 07:29:08 PM
Post by: fwydriver405 on January 20, 2021, 07:29:08 PM
Saw two intersections with double permissive lefts on a recent trip to the University of Vermont for two games:
https://www.google.com/maps/@44.4744303,-73.1954092,3a,35.6y,54.89h,84.69t/data=!3m6!1e1!3m4!1sqU4mNlgDIpby3ZwN85XmVg!2e0!7i16384!8i8192 (this one is confirmed, as I saw the opposing direction also have a concurrent green as well.)
https://www.google.com/maps/@44.4758217,-73.1926487,3a,24.8y,186.4h,85.56t/data=!3m6!1e1!3m4!1sDMQ344T5QDAEkA_uedCzKQ!2e0!7i13312!8i6656
https://www.google.com/maps/@44.4744303,-73.1954092,3a,35.6y,54.89h,84.69t/data=!3m6!1e1!3m4!1sqU4mNlgDIpby3ZwN85XmVg!2e0!7i16384!8i8192 (this one is confirmed, as I saw the opposing direction also have a concurrent green as well.)
https://www.google.com/maps/@44.4758217,-73.1926487,3a,24.8y,186.4h,85.56t/data=!3m6!1e1!3m4!1sDMQ344T5QDAEkA_uedCzKQ!2e0!7i13312!8i6656
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 29, 2021, 02:19:18 PM
Post by: jakeroot on January 29, 2021, 02:19:18 PM
Quote from: fwydriver405 on January 20, 2021, 07:29:08 PM
Saw two intersections with double permissive lefts on a recent trip to the University of Vermont for two games:
https://www.google.com/maps/@44.4744303,-73.1954092,3a,35.6y,54.89h,84.69t/data=!3m6!1e1!3m4!1sqU4mNlgDIpby3ZwN85XmVg!2e0!7i16384!8i8192 (this one is confirmed, as I saw the opposing direction also have a concurrent green as well.)
https://www.google.com/maps/@44.4758217,-73.1926487,3a,24.8y,186.4h,85.56t/data=!3m6!1e1!3m4!1sDMQ344T5QDAEkA_uedCzKQ!2e0!7i13312!8i6656
I continue to be surprised by how many exist in Vermont. Interesting that two would end up so close to each other.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 29, 2021, 02:36:41 PM
Post by: jakeroot on January 29, 2021, 02:36:41 PM
Another in New York City:
Kissena Blvd @ the LIE (I-495) (https://goo.gl/maps/5tFdENtcruvQw9Fz6) (both on-ramps)
Both directions have Texas-style optional straight/left middle lanes. The signal configuration suggests lagging green arrows for both directions.
---
And another in New York City...this place is full of them:
108th St @ the LIE (I-495) (https://goo.gl/maps/cD81uPMrYM12jNcy6) (also both on-ramps)
This one was recently changed to include flashing yellow arrows. The eastbound on-ramp is a true double left turn; the westbound on-ramp includes an option lane (both still use FYAs)
---
To anyone on Long Island...are there others that haven't been mentioned? The one at the LIE & Oyster Bay Rd in Syosset has been mentioned. Far as I know, neither of the above two have come up.
Kissena Blvd @ the LIE (I-495) (https://goo.gl/maps/5tFdENtcruvQw9Fz6) (both on-ramps)
Both directions have Texas-style optional straight/left middle lanes. The signal configuration suggests lagging green arrows for both directions.
---
And another in New York City...this place is full of them:
108th St @ the LIE (I-495) (https://goo.gl/maps/cD81uPMrYM12jNcy6) (also both on-ramps)
This one was recently changed to include flashing yellow arrows. The eastbound on-ramp is a true double left turn; the westbound on-ramp includes an option lane (both still use FYAs)
---
To anyone on Long Island...are there others that haven't been mentioned? The one at the LIE & Oyster Bay Rd in Syosset has been mentioned. Far as I know, neither of the above two have come up.
Title: Re: Double left turns with permissive phasing
Post by: SkyPesos on January 29, 2021, 02:57:06 PM
Post by: SkyPesos on January 29, 2021, 02:57:06 PM
Not really the same as the ones in this thread; it's quite the opposite but interesting.
At the Mexico and Jungermann intersection (https://www.google.com/maps/@38.7914177,-90.5760139,3a,86.1y,275.71h,84.83t/data=!3m6!1e1!3m4!1smRe-9-PAQ4G6UV370S_koA!2e0!7i13312!8i6656) in St. Charles, MO, similar to Jakeroot's examples above, the center lane is an option lane between left and straight. The difference is that both lanes are in a protected left phasing, which means that left turning cars in the center lane have to wait there until the left arrow in the doghouse is green. This has been fixed later with 2 left turn only lanes later.
At the Mexico and Jungermann intersection (https://www.google.com/maps/@38.7914177,-90.5760139,3a,86.1y,275.71h,84.83t/data=!3m6!1e1!3m4!1smRe-9-PAQ4G6UV370S_koA!2e0!7i13312!8i6656) in St. Charles, MO, similar to Jakeroot's examples above, the center lane is an option lane between left and straight. The difference is that both lanes are in a protected left phasing, which means that left turning cars in the center lane have to wait there until the left arrow in the doghouse is green. This has been fixed later with 2 left turn only lanes later.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 29, 2021, 03:24:42 PM
Post by: jakeroot on January 29, 2021, 03:24:42 PM
Quote from: SkyPesos on January 29, 2021, 02:57:06 PM
Not really the same as the ones in this thread; it's quite the opposite but interesting.
At the Mexico and Jungermann intersection (https://www.google.com/maps/@38.7914177,-90.5760139,3a,86.1y,275.71h,84.83t/data=!3m6!1e1!3m4!1smRe-9-PAQ4G6UV370S_koA!2e0!7i13312!8i6656) in St. Charles, MO, similar to Jakeroot's examples above, the center lane is an option lane between left and straight. The difference is that both lanes are in a protected left phasing, which means that left turning cars in the center lane have to wait there until the left arrow in the doghouse is green. This has been fixed later with 2 left turn only lanes later.
That would be the standard approach in most areas for double left turns involving an option lane. The only difference might be the use of a 4-section signal in the middle (like this example (https://goo.gl/maps/AJb3JW9tiWURXU1g7) near me).
Before anyone else shares additional examples of split-phasing: remember that this thread is for permissive lefts, not protected lefts :D.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on January 29, 2021, 09:09:07 PM
Post by: fwydriver405 on January 29, 2021, 09:09:07 PM
Quote from: jakeroot on January 29, 2021, 02:19:18 PMQuote from: fwydriver405 on January 20, 2021, 07:29:08 PM
Saw two intersections with double permissive lefts on a recent trip to the University of Vermont for two games:
https://www.google.com/maps/@44.4744303,-73.1954092,3a,35.6y,54.89h,84.69t/data=!3m6!1e1!3m4!1sqU4mNlgDIpby3ZwN85XmVg!2e0!7i16384!8i8192 (this one is confirmed, as I saw the opposing direction also have a concurrent green as well.)
https://www.google.com/maps/@44.4758217,-73.1926487,3a,24.8y,186.4h,85.56t/data=!3m6!1e1!3m4!1sDMQ344T5QDAEkA_uedCzKQ!2e0!7i13312!8i6656
I continue to be surprised by how many exist in Vermont. Interesting that two would end up so close to each other.
Speaking of Vermont... I wonder if this double left in St Albans VT is still running permissive/protected at all since 2015, since the newer GSV's show this signal to run in protected only mode. (UPDATE JUN 2022: Still in Protected only mode 24/7)
2015 GSV (permissve/protected) (https://www.google.com/maps/@44.8410292,-73.0837251,3a,28.9y,146.28h,87.99t/data=!3m7!1e1!3m5!1ss_p1yt6m1y8CWAY0RqqLgA!2e0!5s20151101T000000!7i13312!8i6656), Oct 2018 GSV (protected only?) (https://www.google.com/maps/@44.8408616,-73.0836262,3a,65.7y,143.64h,85.76t/data=!3m7!1e1!3m5!1sSLugCFgWB88T3YLoo3aNxg!2e0!5s20181001T000000!7i13312!8i6656)
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 30, 2021, 12:10:10 PM
Post by: jakeroot on January 30, 2021, 12:10:10 PM
Quote from: fwydriver405 on January 29, 2021, 09:09:07 PMQuote from: jakeroot on January 29, 2021, 02:19:18 PMQuote from: fwydriver405 on January 20, 2021, 07:29:08 PM
Saw two intersections with double permissive lefts on a recent trip to the University of Vermont for two games:
https://www.google.com/maps/@44.4744303,-73.1954092,3a,35.6y,54.89h,84.69t/data=!3m6!1e1!3m4!1sqU4mNlgDIpby3ZwN85XmVg!2e0!7i16384!8i8192 (this one is confirmed, as I saw the opposing direction also have a concurrent green as well.)
https://www.google.com/maps/@44.4758217,-73.1926487,3a,24.8y,186.4h,85.56t/data=!3m6!1e1!3m4!1sDMQ344T5QDAEkA_uedCzKQ!2e0!7i13312!8i6656
I continue to be surprised by how many exist in Vermont. Interesting that two would end up so close to each other.
Speaking of Vermont... I wonder if this double left in St Albans VT is still running permissive/protected at all since 2015, since the newer GSV's show this signal to run in protected only mode.
2015 GSV (permissve/protected) (https://www.google.com/maps/@44.8410292,-73.0837251,3a,28.9y,146.28h,87.99t/data=!3m7!1e1!3m5!1ss_p1yt6m1y8CWAY0RqqLgA!2e0!5s20151101T000000!7i13312!8i6656), Oct 2018 GSV (protected only?) (https://www.google.com/maps/@44.8408616,-73.0836262,3a,65.7y,143.64h,85.76t/data=!3m7!1e1!3m5!1sSLugCFgWB88T3YLoo3aNxg!2e0!5s20181001T000000!7i13312!8i6656)
I can't find it in this thread, but I recall someone mentioning that it was switched to protected-only. I swear there was a news story accompanying the change, but I cannot find anything.
Title: Re: Double left turns with permissive phasing
Post by: RestrictOnTheHanger on January 30, 2021, 10:16:59 PM
Post by: RestrictOnTheHanger on January 30, 2021, 10:16:59 PM
Quote from: jakeroot on January 29, 2021, 02:36:41 PM
Another in New York City:
Kissena Blvd @ the LIE (I-495) (https://goo.gl/maps/5tFdENtcruvQw9Fz6) (both on-ramps)
Both directions have Texas-style optional straight/left middle lanes. The signal configuration suggests lagging green arrows for both directions.
---
And another in New York City...this place is full of them:
108th St @ the LIE (I-495) (https://goo.gl/maps/cD81uPMrYM12jNcy6) (also both on-ramps)
This one was recently changed to include flashing yellow arrows. The eastbound on-ramp is a true double left turn; the westbound on-ramp includes an option lane (both still use FYAs)
---
To anyone on Long Island...are there others that haven't been mentioned? The one at the LIE & Oyster Bay Rd in Syosset has been mentioned. Far as I know, neither of the above two have come up.
NYC has a few intersections similar to the Kissena @ LIE setup. Those are in fact lagging since NYC doesnt use bimodal arrows.
The 108th st intersection is a recent conversion, I actually posted about it in the FYA thread since I live by there. It used to be like the Kissena setup.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on January 31, 2021, 12:21:55 AM
Post by: Amtrakprod on January 31, 2021, 12:21:55 AM
Quote from: jakeroot on January 30, 2021, 12:10:10 PMThat's too bad. St Albans aint to far from me I'll check it out IRL sometimeQuote from: fwydriver405 on January 29, 2021, 09:09:07 PMQuote from: jakeroot on January 29, 2021, 02:19:18 PMQuote from: fwydriver405 on January 20, 2021, 07:29:08 PM
Saw two intersections with double permissive lefts on a recent trip to the University of Vermont for two games:
https://www.google.com/maps/@44.4744303,-73.1954092,3a,35.6y,54.89h,84.69t/data=!3m6!1e1!3m4!1sqU4mNlgDIpby3ZwN85XmVg!2e0!7i16384!8i8192 (this one is confirmed, as I saw the opposing direction also have a concurrent green as well.)
https://www.google.com/maps/@44.4758217,-73.1926487,3a,24.8y,186.4h,85.56t/data=!3m6!1e1!3m4!1sDMQ344T5QDAEkA_uedCzKQ!2e0!7i13312!8i6656
I continue to be surprised by how many exist in Vermont. Interesting that two would end up so close to each other.
Speaking of Vermont... I wonder if this double left in St Albans VT is still running permissive/protected at all since 2015, since the newer GSV's show this signal to run in protected only mode.
2015 GSV (permissve/protected) (https://www.google.com/maps/@44.8410292,-73.0837251,3a,28.9y,146.28h,87.99t/data=!3m7!1e1!3m5!1ss_p1yt6m1y8CWAY0RqqLgA!2e0!5s20151101T000000!7i13312!8i6656), Oct 2018 GSV (protected only?) (https://www.google.com/maps/@44.8408616,-73.0836262,3a,65.7y,143.64h,85.76t/data=!3m7!1e1!3m5!1sSLugCFgWB88T3YLoo3aNxg!2e0!5s20181001T000000!7i13312!8i6656)
I can't find it in this thread, but I recall someone mentioning that it was switched to protected-only. I swear there was a news story accompanying the change, but I cannot find anything.
iPhone
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 31, 2021, 04:51:42 PM
Post by: jakeroot on January 31, 2021, 04:51:42 PM
Quote from: RestrictOnTheHanger on January 30, 2021, 10:16:59 PM
NYC has a few intersections similar to the Kissena @ LIE setup. Those are in fact lagging since NYC doesnt use bimodal arrows.
The 108th st intersection is a recent conversion, I actually posted about it in the FYA thread since I live by there. It used to be like the Kissena setup.
The setup like the Kissena @ LIE operation makes a lot of sense, at least to me. The tendency to use split-phasing at signals like this seems misguided.
I was pretty sure I had seen that intersection posted somewhere before; almost certainly it would have been your post over there.
Quote from: Amtrakprod on January 31, 2021, 12:21:55 AMQuote from: jakeroot on January 30, 2021, 12:10:10 PMThat's too bad. St Albans aint to far from me I'll check it out IRL sometime
I can't find it in this thread, but I recall someone mentioning that it was switched to protected-only. I swear there was a news story accompanying the change, but I cannot find anything.
If you can get over there late at night, see if it operates with time-of-day phasing.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on January 31, 2021, 08:27:29 PM
Post by: Amtrakprod on January 31, 2021, 08:27:29 PM
Quote from: jakeroot on January 31, 2021, 04:51:42 PMQuote from: RestrictOnTheHanger on January 30, 2021, 10:16:59 PM
NYC has a few intersections similar to the Kissena @ LIE setup. Those are in fact lagging since NYC doesnt use bimodal arrows.
The 108th st intersection is a recent conversion, I actually posted about it in the FYA thread since I live by there. It used to be like the Kissena setup.
The setup like the Kissena @ LIE operation makes a lot of sense, at least to me. The tendency to use split-phasing at signals like this seems misguided.
I was pretty sure I had seen that intersection posted somewhere before; almost certainly it would have been your post over there.Quote from: Amtrakprod on January 31, 2021, 12:21:55 AMQuote from: jakeroot on January 30, 2021, 12:10:10 PMThat's too bad. St Albans aint to far from me I'll check it out IRL sometime
I can't find it in this thread, but I recall someone mentioning that it was switched to protected-only. I swear there was a news story accompanying the change, but I cannot find anything.
If you can get over there late at night, see if it operates with time-of-day phasing.
Once COVID ends I'll check it out. As of now VT has some covid travel things that are annoying.
Good idea to look at night. I hope it's still permissive 🤞
Title: Re: Double left turns with permissive phasing
Post by: RestrictOnTheHanger on February 01, 2021, 12:47:53 AM
Post by: RestrictOnTheHanger on February 01, 2021, 12:47:53 AM
Found another setup in East Meadow, Long Island by chance last week, Merrick Ave at Glenn Curtiss Blvd
https://maps.app.goo.gl/j7jyqiBSVuPoyYLH7
With a bonus double right turn allowed on red from Glenn Curtiss Blvd (overlaps the left turn from Merrick Ave)
https://maps.app.goo.gl/HkMj4G4PhSaLpDBV6
However, the setup may not be MUTCD compliant because the double right turn green arrows overlap with the opposing street's green ball. The double right should use a green ball or FYA when right turning traffic cant conflict with opposing traffic, but this is an outdated setup.
https://maps.app.goo.gl/j7jyqiBSVuPoyYLH7
With a bonus double right turn allowed on red from Glenn Curtiss Blvd (overlaps the left turn from Merrick Ave)
https://maps.app.goo.gl/HkMj4G4PhSaLpDBV6
However, the setup may not be MUTCD compliant because the double right turn green arrows overlap with the opposing street's green ball. The double right should use a green ball or FYA when right turning traffic cant conflict with opposing traffic, but this is an outdated setup.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 01, 2021, 09:48:02 PM
Post by: jakeroot on February 01, 2021, 09:48:02 PM
Quote from: RestrictOnTheHanger on February 01, 2021, 12:47:53 AM
Found another setup in East Meadow, Long Island by chance last week, Merrick Ave at Glenn Curtiss Blvd
https://maps.app.goo.gl/j7jyqiBSVuPoyYLH7
With a bonus double right turn allowed on red from Glenn Curtiss Blvd (overlaps the left turn from Merrick Ave)
https://maps.app.goo.gl/HkMj4G4PhSaLpDBV6
However, the setup may not be MUTCD compliant because the double right turn green arrows overlap with the opposing street's green ball. The double right should use a green ball or FYA when right turning traffic cant conflict with opposing traffic, but this is an outdated setup.
The double right turn should definitely use green orbs or FYAs, yeah.
Otherwise, great example! Another classic setup from New York.
New York quickly seems to be gaining as one of the states with the most examples. Colorado is still first, followed by Arizona, then Texas, then likely Minnesota and probably New York shortly thereafter. Particularly when you include NYC, New York has more examples than I think anyone here realized at first.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on February 03, 2021, 11:51:19 PM
Post by: mrsman on February 03, 2021, 11:51:19 PM
Quote from: jakeroot on February 01, 2021, 09:48:02 PMQuote from: RestrictOnTheHanger on February 01, 2021, 12:47:53 AM
Found another setup in East Meadow, Long Island by chance last week, Merrick Ave at Glenn Curtiss Blvd
https://maps.app.goo.gl/j7jyqiBSVuPoyYLH7
With a bonus double right turn allowed on red from Glenn Curtiss Blvd (overlaps the left turn from Merrick Ave)
https://maps.app.goo.gl/HkMj4G4PhSaLpDBV6
However, the setup may not be MUTCD compliant because the double right turn green arrows overlap with the opposing street's green ball. The double right should use a green ball or FYA when right turning traffic cant conflict with opposing traffic, but this is an outdated setup.
The double right turn should definitely use green orbs or FYAs, yeah.
Otherwise, great example! Another classic setup from New York.
New York quickly seems to be gaining as one of the states with the most examples. Colorado is still first, followed by Arizona, then Texas, then likely Minnesota and probably New York shortly thereafter. Particularly when you include NYC, New York has more examples than I think anyone here realized at first.
CO and AZ examples are more in line with the traditional notion of the mountain west, being freer, more individualistic. Drivers can decide for themselves what is safe and allowing for the permissive turn without the need for excessive over-regulation is in line with that mindset. These double lefts are more traditional - they occur in the same circumstances as permissive single lefts, just with the addition of an additional left turn lane to capture more people. To an extent, to make this work out better, CO and AZ will feature pavement markings to guide drivers where to wait while they wait for a gap in opposing traffic.
NYC is nothing like CO and AZ. Quite the opposite, particularly in light of the fact that RTOR is generally prohibited there at every intersection, unless a sign permits it. So what can we attribute the significant number of permissive double lefts that exist there? It in fact speaks to the fact that traffic is generally so heavy that the ability to make a left during the permissive phase is largely theoretical. In NYC, this is commonly found as a double left with an option lane, in places where the opposing left is prohibited, and where the protected signal is a lagging left. Taking the intersection of 108th/LIE as an example, this is an intersection that is almost always too congested to even have the opportunity for a gap during the permissive phase. Instead, the lefts will actually take place during the protected lagging phase. This is done because the streets are often too narrow to allow for two left turn lanes and two straight through lanes, yet there is enough traffic to justify two lanes straight and two lanes left, but only three lanes to work with - so an option lane is used. If one is in the option lane, a straight driver would be blocked by a left turning driver initially - but fortunately, due to the lagging left, when the green arrow comes, both straight and left turning drivers in the option lane can complete their movements without blocking each other. And as there is no opposing driver waiting to make a left turn (in NYC the permissive double left option lane is almost always a turn from a two-way to a one-way street or expressway ramp), there should be no problem with worrying about where the drivers would wait, while they wait for a gap in opposing traffic to complete their turns.
A long way of saying that AZ and CO with wide open spaces and a free mind set have a regular double permissive turn. NYC allows it out of necessity, but due to on-the-ground circumstances, the ability to turn during the permissive phase is actually quite rare and for all intents and purposes the signal behaves like a protected turn during most hours of the day.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 05, 2021, 08:48:40 PM
Post by: jakeroot on February 05, 2021, 08:48:40 PM
Quote from: mrsman on February 03, 2021, 11:51:19 PM
CO and AZ examples are more in line with the traditional notion of the mountain west, being freer, more individualistic. Drivers can decide for themselves what is safe and allowing for the permissive turn without the need for excessive over-regulation is in line with that mindset. These double lefts are more traditional - they occur in the same circumstances as permissive single lefts, just with the addition of an additional left turn lane to capture more people. To an extent, to make this work out better, CO and AZ will feature pavement markings to guide drivers where to wait while they wait for a gap in opposing traffic.
NYC is nothing like CO and AZ. Quite the opposite, particularly in light of the fact that RTOR is generally prohibited there at every intersection, unless a sign permits it. So what can we attribute the significant number of permissive double lefts that exist there? It in fact speaks to the fact that traffic is generally so heavy that the ability to make a left during the permissive phase is largely theoretical. In NYC, this is commonly found as a double left with an option lane, in places where the opposing left is prohibited, and where the protected signal is a lagging left. Taking the intersection of 108th/LIE as an example, this is an intersection that is almost always too congested to even have the opportunity for a gap during the permissive phase. Instead, the lefts will actually take place during the protected lagging phase. This is done because the streets are often too narrow to allow for two left turn lanes and two straight through lanes, yet there is enough traffic to justify two lanes straight and two lanes left, but only three lanes to work with - so an option lane is used. If one is in the option lane, a straight driver would be blocked by a left turning driver initially - but fortunately, due to the lagging left, when the green arrow comes, both straight and left turning drivers in the option lane can complete their movements without blocking each other. And as there is no opposing driver waiting to make a left turn (in NYC the permissive double left option lane is almost always a turn from a two-way to a one-way street or expressway ramp), there should be no problem with worrying about where the drivers would wait, while they wait for a gap in opposing traffic to complete their turns.
A long way of saying that AZ and CO with wide open spaces and a free mind set have a regular double permissive turn. NYC allows it out of necessity, but due to on-the-ground circumstances, the ability to turn during the permissive phase is actually quite rare and for all intents and purposes the signal behaves like a protected turn during most hours of the day.
Your explanation of New York certainly reminds me of the double left turn I put in the OP:
Quote from: jakeroot on December 14, 2015, 02:01:17 AM
Here's an image of a typical FYA setup (James St at 6th Ave, Seattle):
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F9TJxDfS.png&hash=ef332dc58fd153983f86f1f0c7f2d4c2b6c8e9a1)
(Although you see four signals, there is only three approach lanes; the center lane is an option lane).
In practice, only a couple cars ever get to turn during the permissive phase, before it falls into the lagging green arrow phase (exactly like the NY examples -- this particular example is basically identical to the north-to-westbound movement between 108th and the LIE). So while there may be some inherent increase in danger with a double permissive left turn in these very busy areas, there's very little opportunity for drivers to actually engage in whatever might be described as potentially risky behavior, such as punching through a small gap or turning blindly, etc.
I think a bigger question might be how those NYC examples, or even those outside the city (I think there's a couple?), operate later at night. As far as I know, they are not set to become split-phase at night, and traffic even in NYC does eventually peter out to relatively quiet levels. The lagging phase may remain, but without as much oncoming traffic, there is certainly less of a "never any gap" situation.
At the end of the day, you're absolutely right that it comes down to mindsets. I don't think Colorado or Arizona (primarily Tucson) make them as common as they want because they have extensive studies that show them as massively safe. Rather, they just install them because the overall mindset is more about letting drivers make the calls, and letting them take the responsibility at that point. It does make me wonder if stuff like Vision Zero, which places the onus on the city engineering department to improve safety, may result in a change of mindset in places like Colorado or Tucson. I think it already has in Tucson, where FYAs with pedestrian lock-out are now very common.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on February 09, 2021, 09:44:21 PM
Post by: mrsman on February 09, 2021, 09:44:21 PM
Quote from: jakeroot on February 05, 2021, 08:48:40 PM
(Although you see four signals, there is only three approach lanes; the center lane is an option lane).
In practice, only a couple cars ever get to turn during the permissive phase, before it falls into the lagging green arrow phase (exactly like the NY examples -- this particular example is basically identical to the north-to-westbound movement between 108th and the LIE). So while there may be some inherent increase in danger with a double permissive left turn in these very busy areas, there's very little opportunity for drivers to actually engage in whatever might be described as potentially risky behavior, such as punching through a small gap or turning blindly, etc.
I think a bigger question might be how those NYC examples, or even those outside the city (I think there's a couple?), operate later at night. As far as I know, they are not set to become split-phase at night, and traffic even in NYC does eventually peter out to relatively quiet levels. The lagging phase may remain, but without as much oncoming traffic, there is certainly less of a "never any gap" situation.
At the end of the day, you're absolutely right that it comes down to mindsets. I don't think Colorado or Arizona (primarily Tucson) make them as common as they want because they have extensive studies that show them as massively safe. Rather, they just install them because the overall mindset is more about letting drivers make the calls, and letting them take the responsibility at that point. It does make me wonder if stuff like Vision Zero, which places the onus on the city engineering department to improve safety, may result in a change of mindset in places like Colorado or Tucson. I think it already has in Tucson, where FYAs with pedestrian lock-out are now very common.
The vast majority of NYC lights are on timer only - they are not demand responsive at all. The signals will likely cycle through in the same manner as they do during rush hour, although there could be some timing adjustments as well. Its definitely true that even if there were nobody wanting to make the left, the lagging left arrows would still light up.
So in lighter traffic, permissive lefts would be possible at these intersections. And using both lanes is also possible at these intersections. But given the heavy traffic, large number of pedestrians, and aggressive driving culture, what's possible doesn't equal what is actual. So you may be able to use both lanes to make a permissive left in off-hours, but it's not the norm.
Title: Re: Double left turns with permissive phasing
Post by: betfourteen on February 17, 2021, 08:26:56 AM
Post by: betfourteen on February 17, 2021, 08:26:56 AM
Another Nassau County, NY find
Wantagh Ave & Old Jerusalem Rd https://goo.gl/maps/BDyFacd7pFBr2ZyZ6
Wantagh Ave & Old Jerusalem Rd https://goo.gl/maps/BDyFacd7pFBr2ZyZ6
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 17, 2021, 01:12:01 PM
Post by: jakeroot on February 17, 2021, 01:12:01 PM
Quote from: betfourteen on February 17, 2021, 08:26:56 AM
Another Nassau County, NY find
Wantagh Ave & Old Jerusalem Rd https://goo.gl/maps/BDyFacd7pFBr2ZyZ6
Another great Long Island find. What is it with this place?!
Odd that the oncoming single-lane left turn was changed from permissive-only (https://goo.gl/maps/Ft3QFR68wDnWPiWG6) to protected-only (https://goo.gl/maps/ju3H9ncKqonZjMhRA).
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 17, 2021, 05:07:38 PM
Post by: jakeroot on February 17, 2021, 05:07:38 PM
We've already covered Colorado, but I found this unique example that once existed in Colorado Springs. The right-most left turn lane had two options, I-25 or Chestnut St:
Fillmore St @ I-25/Chestnut St (https://goo.gl/maps/SfUDyqu3kApvP2bt7)
This made it possibly the only double permissive left turn that allowed traffic to turn onto more than one street. Most single lane left turns that allow multiple exits are protected-only (https://goo.gl/maps/LK1XMZDsHGtLxpvd9) in this country (with exceptions (https://youtu.be/TxW7rb7g5XI), of course), so this was doubly interesting.
Quick history: Chestnut St was rerouted about 300 feet to the west around 2014, and I-25/Fillmore is now a DDI. The left turn operated with double FYA signals (https://goo.gl/maps/XWmdkjea9bw935Cw5) for a short time after Chestnut was rerouted (turns were only onto I-25 at that point), before it was converted to a DDI a couple years later.
Fillmore St @ I-25/Chestnut St (https://goo.gl/maps/SfUDyqu3kApvP2bt7)
This made it possibly the only double permissive left turn that allowed traffic to turn onto more than one street. Most single lane left turns that allow multiple exits are protected-only (https://goo.gl/maps/LK1XMZDsHGtLxpvd9) in this country (with exceptions (https://youtu.be/TxW7rb7g5XI), of course), so this was doubly interesting.
Quick history: Chestnut St was rerouted about 300 feet to the west around 2014, and I-25/Fillmore is now a DDI. The left turn operated with double FYA signals (https://goo.gl/maps/XWmdkjea9bw935Cw5) for a short time after Chestnut was rerouted (turns were only onto I-25 at that point), before it was converted to a DDI a couple years later.
Title: Re: Double left turns with permissive phasing
Post by: RestrictOnTheHanger on February 18, 2021, 12:08:05 AM
Post by: RestrictOnTheHanger on February 18, 2021, 12:08:05 AM
Quote from: jakeroot on February 17, 2021, 01:12:01 PMQuote from: betfourteen on February 17, 2021, 08:26:56 AM
Another Nassau County, NY find
Wantagh Ave & Old Jerusalem Rd https://goo.gl/maps/BDyFacd7pFBr2ZyZ6
Another great Long Island find. What is it with this place?!
Odd that the oncoming single-lane left turn was changed from permissive-only (https://goo.gl/maps/Ft3QFR68wDnWPiWG6) to protected-only (https://goo.gl/maps/ju3H9ncKqonZjMhRA).
Maybe the change was due to the curve. Also its odd that the double permissive left is used in Nassau but almost nonexistent in Suffolk.
Title: Re: Double left turns with permissive phasing
Post by: betfourteen on March 08, 2021, 11:39:38 AM
Post by: betfourteen on March 08, 2021, 11:39:38 AM
What's this I see? Nassau County, NY coming in again! https://goo.gl/maps/bJa6yZ4vtNMDaEVn6
Although, the opposing direction isn't particularly busy (Exit for DSW Shoe Store and a catering hall), it still can get busy after an event at the hall or excess shoppers at DSW)
Although, the opposing direction isn't particularly busy (Exit for DSW Shoe Store and a catering hall), it still can get busy after an event at the hall or excess shoppers at DSW)
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 09, 2021, 06:18:42 PM
Post by: jakeroot on March 09, 2021, 06:18:42 PM
Quote from: betfourteen on March 08, 2021, 11:39:38 AM
What's this I see? Nassau County, NY coming in again! https://goo.gl/maps/bJa6yZ4vtNMDaEVn6
Although, the opposing direction isn't particularly busy (Exit for DSW Shoe Store and a catering hall), it still can get busy after an event at the hall or excess shoppers at DSW)
"No way, that's probably split--" "never mind (https://goo.gl/maps/jzo4AvwC7ARzH3kp6)".
All of these examples must be the legacy of a few engineers. Or perhaps influence from New York City? It's very intriguing.
Title: Re: Double left turns with permissive phasing
Post by: betfourteen on March 10, 2021, 08:00:41 AM
Post by: betfourteen on March 10, 2021, 08:00:41 AM
Quote from: jakeroot on March 09, 2021, 06:18:42 PMQuote from: betfourteen on March 08, 2021, 11:39:38 AM
What's this I see? Nassau County, NY coming in again! https://goo.gl/maps/bJa6yZ4vtNMDaEVn6
Although, the opposing direction isn't particularly busy (Exit for DSW Shoe Store and a catering hall), it still can get busy after an event at the hall or excess shoppers at DSW)
"No way, that's probably split--" "never mind (https://goo.gl/maps/jzo4AvwC7ARzH3kp6)".
All of these examples must be the legacy of a few engineers. Or perhaps influence from New York City? It's very intriguing.
That was my first thought that it was split too....But then I drove through it to find out for myself that 'twas not split.
Title: Re: Double left turns with permissive phasing
Post by: betfourteen on March 11, 2021, 01:57:27 PM
Post by: betfourteen on March 11, 2021, 01:57:27 PM
Here we go again ... Nassau County, NY:
#1: https://goo.gl/maps/ZzRGPBg6Yyem7SUS8
#2: https://goo.gl/maps/A6zxNbwxAZseD8Av5
And no, it's not split phased either: :pan:
https://goo.gl/maps/Dg7UGrSQjDAYHu3F8
These intersections, and road in general, are horrific during the holiday season and on weekends.
#1: https://goo.gl/maps/ZzRGPBg6Yyem7SUS8
#2: https://goo.gl/maps/A6zxNbwxAZseD8Av5
And no, it's not split phased either: :pan:
https://goo.gl/maps/Dg7UGrSQjDAYHu3F8
These intersections, and road in general, are horrific during the holiday season and on weekends.
Title: Re: Double left turns with permissive phasing
Post by: RestrictOnTheHanger on March 16, 2021, 05:38:20 PM
Post by: RestrictOnTheHanger on March 16, 2021, 05:38:20 PM
Another one in Queens, with a bonus awkward left turn signal
Queens Blvd at Hillside Ave
https://maps.app.goo.gl/NvujbpSa8wSagBZp9
Queens Blvd at Hillside Ave
https://maps.app.goo.gl/NvujbpSa8wSagBZp9
Title: Re: Double left turns with permissive phasing
Post by: kphoger on March 17, 2021, 09:56:52 AM
Post by: kphoger on March 17, 2021, 09:56:52 AM
Quote from: RestrictOnTheHanger on March 16, 2021, 05:38:20 PM
Another one in Queens, with a bonus awkward left turn signal
Queens Blvd at Hillside Ave
https://maps.app.goo.gl/NvujbpSa8wSagBZp9
Now, this just looks wacky to me (https://goo.gl/maps/zcmUfwnFRwuGimMJ9).
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 17, 2021, 01:24:00 PM
Post by: jakeroot on March 17, 2021, 01:24:00 PM
Quote from: RestrictOnTheHanger on March 16, 2021, 05:38:20 PM
Another one in Queens, with a bonus awkward left turn signal
Queens Blvd at Hillside Ave
https://maps.app.goo.gl/NvujbpSa8wSagBZp9
This was actually one of the earlier mentions in this thread. cl94 brought it up when I mentioned the Flatbush/Tillary intersection like 15 pages ago:
Quote from: cl94 on May 14, 2017, 05:40:18 PM
Having family nearby until relatively recently, this was the only dual-permissive left turn installation I knew of anywhere until I was almost 9. It's still one of the less than 5 I have seen in person. I'm convinced that this was only done because opposing turns are prohibited and sightlines are wide-open. I do NOT know of another dual permissive left in New York that has opposing left turns (excluding the east end of Queens Blvd (https://www.google.com/maps/@40.7043938,-73.8154668,3a,75y,150.56h,77.42t/data=!3m6!1e1!3m4!1s_py5QYyiWGRB1Q4-xP_OzQ!2e0!7i13312!8i6656), which has open sightlines due to the way the WB ROW shifts).
Title: Re: Double left turns with permissive phasing
Post by: betfourteen on March 17, 2021, 03:20:01 PM
Post by: betfourteen on March 17, 2021, 03:20:01 PM
Hello again Nassau County - https://goo.gl/maps/yw3BUwhuvEWp9q4C7
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 19, 2021, 01:46:20 PM
Post by: jakeroot on March 19, 2021, 01:46:20 PM
(I feel like someone posted this already, but I cannot confirm)
See reply #535
Title: Re: Double left turns with permissive phasing
Post by: jeffandnicole on March 19, 2021, 01:53:19 PM
Post by: jeffandnicole on March 19, 2021, 01:53:19 PM
Quote from: betfourteen on March 17, 2021, 03:20:01 PM
Hello again Nassau County - https://goo.gl/maps/yw3BUwhuvEWp9q4C7
Quote from: jakeroot on March 19, 2021, 01:46:20 PM
And again in Nassau County: Fortunoff Way @ Old Country Rd (https://goo.gl/maps/2DpKai7RMXg5nGct5)
(I feel like someone posted this already, but I cannot confirm)
These shouldn't be permissive phasing as they aren't true double lefts. With the dual left/thru lane, they should only be split phasing.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 19, 2021, 02:01:08 PM
Post by: jakeroot on March 19, 2021, 02:01:08 PM
Quote from: jeffandnicole on March 19, 2021, 01:53:19 PMQuote from: betfourteen on March 17, 2021, 03:20:01 PM
Hello again Nassau County - https://goo.gl/maps/yw3BUwhuvEWp9q4C7Quote from: jakeroot on March 19, 2021, 01:46:20 PM
And again in Nassau County: Fortunoff Way @ Old Country Rd (https://goo.gl/maps/2DpKai7RMXg5nGct5)
(I feel like someone posted this already, but I cannot confirm)
These shouldn't be permissive phasing as they aren't true double lefts. With the dual left/thru lane, they should only be split phasing.
Split-phasing is usually used in these circumstances because of policy, not because it actually needs to be split-phased for safety's sake or whatever.
Title: Re: Double left turns with permissive phasing
Post by: betfourteen on March 19, 2021, 02:13:23 PM
Post by: betfourteen on March 19, 2021, 02:13:23 PM
Quote from: jakeroot on March 19, 2021, 01:46:20 PM
And again in Nassau County: Fortunoff Way @ Old Country Rd (https://goo.gl/maps/2DpKai7RMXg5nGct5)
(I feel like someone posted this already, but I cannot confirm)
Yes, #535 ... From yours truly
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 19, 2021, 03:48:23 PM
Post by: jakeroot on March 19, 2021, 03:48:23 PM
Quote from: betfourteen on March 19, 2021, 02:13:23 PMQuote from: jakeroot on March 19, 2021, 01:46:20 PM
And again in Nassau County: Fortunoff Way @ Old Country Rd (https://goo.gl/maps/2DpKai7RMXg5nGct5)
(I feel like someone posted this already, but I cannot confirm)
Yes, #535 ... From yours truly
Thank you. I edited my post.
Title: Re: Double left turns with permissive phasing
Post by: HTM Duke on May 18, 2021, 08:52:05 PM
Post by: HTM Duke on May 18, 2021, 08:52:05 PM
Apologies if I'm mistaken, but I believe I've found Virginia's first entry into this category, at the intersection of Reservoir St at MLK Jr Way in Harrisonburg. No doubt this only happened because of Harrisonburg's incorporated city status. While the arrows aren't clearly visible in Streetview (though zooming in on the signal faces shows hints of them), I was in Harrisonburg last week and saw the setup in action.
https://goo.gl/maps/St4ph4AKxskVUDuq5
https://goo.gl/maps/St4ph4AKxskVUDuq5
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on May 19, 2021, 12:58:43 AM
Post by: jakeroot on May 19, 2021, 12:58:43 AM
Quote from: HTM Duke on May 18, 2021, 08:52:05 PM
Apologies if I'm mistaken, but I believe I've found Virginia's first entry into this category, at the intersection of Reservoir St at MLK Jr Way in Harrisonburg. No doubt this only happened because of Harrisonburg's incorporated city status. While the arrows aren't clearly visible in Streetview (though zooming in on the signal faces shows hints of them), I was in Harrisonburg last week and saw the setup in action.
https://goo.gl/maps/St4ph4AKxskVUDuq5
That's neat! Very unique setup too, given how they built it out of an old oncoming lane. Must be some serious left turn traffic.
It's not the only permissive double left in Virginia, but it's one of maybe two; there is another onto a freeway somewhere in the state.
Title: Re: Double left turns with permissive phasing
Post by: Amtrakprod on June 12, 2021, 10:44:29 PM
Post by: Amtrakprod on June 12, 2021, 10:44:29 PM
Columbus: https://www.google.com/maps/@39.9591571,-82.9969848,3a,31.6y,263.21h,84.49t/data=!3m6!1e1!3m4!1so8qZuLlXT8fQgnGq4iJXHA!2e0!7i16384!8i8192!5m1!1e3
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on June 13, 2021, 11:25:20 AM
Post by: jakeroot on June 13, 2021, 11:25:20 AM
Quote from: Amtrakprod on June 12, 2021, 10:44:29 PM
Columbus: https://www.google.com/maps/@39.9591571,-82.9969848,3a,31.6y,263.21h,84.49t/data=!3m6!1e1!3m4!1so8qZuLlXT8fQgnGq4iJXHA!2e0!7i16384!8i8192!5m1!1e3
Great use case for a permissive left with two lanes. Since I'm coming traffic is a minor driveway, there's really no reason to split-phase. It would be especially stupid since it's a one-way street, and split-phasing would completely block through traffic despite not having any oncoming lefts. Not that there would be much anyway.
Title: Re: Double left turns with permissive phasing
Post by: Ned Weasel on July 01, 2021, 06:46:50 PM
Post by: Ned Weasel on July 01, 2021, 06:46:50 PM
I finally saw a modern local one, complete with FYAs: https://goo.gl/maps/cHRTRxb4Y68qZs5Q6
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 02, 2021, 01:57:17 PM
Post by: jakeroot on July 02, 2021, 01:57:17 PM
Quote from: stridentweasel on July 01, 2021, 06:46:50 PM
I finally saw a modern local one, complete with FYAs: https://goo.gl/maps/cHRTRxb4Y68qZs5Q6
Nice find! Would have loved to see a third FYA signal on the far left mast, but I get the feeling such signals are not so common in Kansas.
I appreciate that people continue to keep their eye out for these.
Title: Re: Double left turns with permissive phasing
Post by: roadfro on July 02, 2021, 07:39:54 PM
Post by: roadfro on July 02, 2021, 07:39:54 PM
I'm currently in Denver for a few days. While driving about yesterday, I encountered one of these on SW-bound Wewatta at Speer Blvd (sorry, posting on phone and couldn't easily get a Street View link). Two full turn lanes with FYA displays, despite it seeming that much of the Denver area still uses offset doghouses for PPLT displays.
EDIT: Looks like there's also one in the opposite direction.
EDIT: Looks like there's also one in the opposite direction.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 02, 2021, 08:59:34 PM
Post by: jakeroot on July 02, 2021, 08:59:34 PM
Quote from: roadfro on July 02, 2021, 07:39:54 PM
I'm currently in Denver for a few days. While driving about yesterday, I encountered one of these on SW-bound Wewatta at Speer Blvd (sorry, posting on phone and couldn't easily get a Street View link). Two full turn lanes with FYA displays, despite it seeming that much of the Denver area still uses offset doghouses for PPLT displays.
EDIT: Looks like there's also one in the opposite direction.
Oh, yeah. Colorado is full of these. In fact, as far as I know, CDOT is the only agency that doesn't seem to regularly install them. Pretty much every city in Colorado has double permissive lefts, with many transitioning to FYAs over the last ten years. The only rule of thumb seems to be protected-only when the double left is extremely busy, or if there are more than two left turn lanes.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 08, 2021, 03:38:11 AM
Post by: jakeroot on July 08, 2021, 03:38:11 AM
Slight bump to refer to an old post:
For some reason, this intersection (Sloat/19th) came up again in another circle, and so I did a little research this time around.
I found this article from SFGate (https://www.sfgate.com/bayarea/article/Deadly-S-F-intersection-gets-left-turn-signal-3301577.php) that talks a bit more about the history of the intersection.
Prior to 2007, the double left turn (with the optional left/straight lane) had existed but it was fully permissive, no arrows. It seems to have been installed decades ago.
In 2007, the extra protected green arrow was added. It seems to operate for only a few seconds at the end of the cycle to clear any waiting traffic (https://goo.gl/maps/sT2NoJKzrRG3rwQr7). According to the article, this addition of a green arrow took seven years to come to fruition. Both Sloat and 19th are state highways, so Caltrans had to approve the signal changes.
This alone really isn't surprising; cities often have to seek state approval for changes to state highways within their jurisdictions (though certainly not always). What's funny to me is, hearing that, I'm sort of staggered that Caltrans would allow San Francisco to continue operating it with a permissive double left. Based on the seven year delay, I have to assume Caltrans wanted San Francisco to simply switch it to full-time double left with fully-protected phasing, but the city seems to have been firmly against such plans, as evidenced by the current double permissive left turn.
Caltrans is quite well known for being extremely conservative with their signalization practices. Permissive lefts of any sort are hard to come by along state highways. So to think they eventually "gave their blessing" to a double permissive left is pretty nuts. Of course, this approval happened twice: once when the double left was installed in the 1960s (I assume it was permissive then), and then again in 2007 when the arrow was added.
Quote from: fwydriver405 on April 02, 2020, 02:29:32 PMQuote from: mrsman on April 02, 2020, 01:15:18 PMQuote from: deathtopumpkins on April 02, 2020, 09:25:57 AM
IMHO California has way too many protected lefts to ever rank first.
Correct, only first in signal placement. Near dead last in signal operation.
Found this one in Downtown San Francisco (option lane) (https://www.google.com/maps/@37.7782294,-122.4009307,3a,35.3y,115.59h,82.61t/data=!3m6!1e1!3m4!1sJwO5v6S2_xSde0klRgGg_A!2e0!7i16384!8i8192). The left lane can choose between I-80 E or Bryant St, and the middle to Bryant St or continue straight to 5th St. Many drivers I've seen during rush hour, use the middle lane to turn onto I-80 E...
I believe there's another one somewhere in SF but not sure where.
EDIT: A few more -
Van Ness and Broadway (albeit temporary? - 2 left turn lanes converted from left + option) (https://www.google.com/maps/@37.7959908,-122.4235818,3a,26.4y,155.38h,91.91t/data=!3m6!1e1!3m4!1sTZ85n9eIsaQ_vM7CFlG_mw!2e0!7i16384!8i8192)
Sloat Blvd and 19th Ave (https://www.google.com/maps/@37.7345949,-122.4755383,3a,38y,89h,87.54t/data=!3m6!1e1!3m4!1sNR9Or460omA2ZMGojtK6tw!2e0!7i16384!8i8192) (left + option)
For some reason, this intersection (Sloat/19th) came up again in another circle, and so I did a little research this time around.
I found this article from SFGate (https://www.sfgate.com/bayarea/article/Deadly-S-F-intersection-gets-left-turn-signal-3301577.php) that talks a bit more about the history of the intersection.
Prior to 2007, the double left turn (with the optional left/straight lane) had existed but it was fully permissive, no arrows. It seems to have been installed decades ago.
In 2007, the extra protected green arrow was added. It seems to operate for only a few seconds at the end of the cycle to clear any waiting traffic (https://goo.gl/maps/sT2NoJKzrRG3rwQr7). According to the article, this addition of a green arrow took seven years to come to fruition. Both Sloat and 19th are state highways, so Caltrans had to approve the signal changes.
This alone really isn't surprising; cities often have to seek state approval for changes to state highways within their jurisdictions (though certainly not always). What's funny to me is, hearing that, I'm sort of staggered that Caltrans would allow San Francisco to continue operating it with a permissive double left. Based on the seven year delay, I have to assume Caltrans wanted San Francisco to simply switch it to full-time double left with fully-protected phasing, but the city seems to have been firmly against such plans, as evidenced by the current double permissive left turn.
Caltrans is quite well known for being extremely conservative with their signalization practices. Permissive lefts of any sort are hard to come by along state highways. So to think they eventually "gave their blessing" to a double permissive left is pretty nuts. Of course, this approval happened twice: once when the double left was installed in the 1960s (I assume it was permissive then), and then again in 2007 when the arrow was added.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on July 11, 2021, 09:16:30 PM
Post by: mrsman on July 11, 2021, 09:16:30 PM
^^^^^
One more thing about this intersection, 19th/Sloat. As it is a lagging permissive left, in order to avoid yellow trap issues, the opposing left turn (Sloat WB to 19th SB) is prohibited. But if you look carefully at the geometry, you can see that this wasn't always the case. This now prohibited left turn has a left turn pocket in the median. So, presumably, before the green arrow was installed for the EB to NB movement, the WB to SB left turn was allowed and used the pocket.
One more thing about this intersection, 19th/Sloat. As it is a lagging permissive left, in order to avoid yellow trap issues, the opposing left turn (Sloat WB to 19th SB) is prohibited. But if you look carefully at the geometry, you can see that this wasn't always the case. This now prohibited left turn has a left turn pocket in the median. So, presumably, before the green arrow was installed for the EB to NB movement, the WB to SB left turn was allowed and used the pocket.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 12, 2021, 02:12:59 AM
Post by: jakeroot on July 12, 2021, 02:12:59 AM
Quote from: mrsman on July 11, 2021, 09:16:30 PM
^^^^^
One more thing about this intersection, 19th/Sloat. As it is a lagging permissive left, in order to avoid yellow trap issues, the opposing left turn (Sloat WB to 19th SB) is prohibited. But if you look carefully at the geometry, you can see that this wasn't always the case. This now prohibited left turn has a left turn pocket in the median. So, presumably, before the green arrow was installed for the EB to NB movement, the WB to SB left turn was allowed and used the pocket.
Going back in historic satellite imagery, it seems that lane has been blocked off since at least the 60s (https://www.historicaerials.com/location/37.7346328425705/-122.47479492136192/1968/18). With that double left turn, it seems visibility would have been poor enough that it was just easier to eliminate it. Seems to have been replaced by U-turn maneuver at 21st.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on July 12, 2021, 10:12:03 AM
Post by: mrsman on July 12, 2021, 10:12:03 AM
Quote from: jakeroot on July 12, 2021, 02:12:59 AMQuote from: mrsman on July 11, 2021, 09:16:30 PM
^^^^^
One more thing about this intersection, 19th/Sloat. As it is a lagging permissive left, in order to avoid yellow trap issues, the opposing left turn (Sloat WB to 19th SB) is prohibited. But if you look carefully at the geometry, you can see that this wasn't always the case. This now prohibited left turn has a left turn pocket in the median. So, presumably, before the green arrow was installed for the EB to NB movement, the WB to SB left turn was allowed and used the pocket.
Going back in historic satellite imagery, it seems that lane has been blocked off since at least the 60s (https://www.historicaerials.com/location/37.7346328425705/-122.47479492136192/1968/18). With that double left turn, it seems visibility would have been poor enough that it was just easier to eliminate it. Seems to have been replaced by U-turn maneuver at 21st.
True. It seems that many of the permissive double lefts in CA occur in situations where the opposing left is prohibited (or at least restricted to left on arrow only). Part of the reason is that drivers making the opposing left could advance and camp in the middle of the intersection while they wait for the gap. This will certainly impact the visibility of traffic making the double left.
So I guess when the city decided that a double left was appropriate, they then prohibited the opposing left. Makes sense.
Title: Re: Double left turns with permissive phasing
Post by: kphoger on July 12, 2021, 02:11:41 PM
Post by: kphoger on July 12, 2021, 02:11:41 PM
Quote from: mrsman on July 12, 2021, 10:12:03 AM
It seems that many of the permissive double lefts in CA occur in situations where the opposing left is prohibited (or at least restricted to left on arrow only). Part of the reason is that drivers making the opposing left could advance and camp in the middle of the intersection while they wait for the gap.
I think that's a reasonable concern.
Title: Re: Double left turns with permissive phasing
Post by: Ned Weasel on July 21, 2021, 06:42:55 AM
Post by: Ned Weasel on July 21, 2021, 06:42:55 AM
Quote from: jakeroot on July 02, 2021, 01:57:17 PMQuote from: stridentweasel on July 01, 2021, 06:46:50 PM
I finally saw a modern local one, complete with FYAs: https://goo.gl/maps/cHRTRxb4Y68qZs5Q6
Nice find! Would have loved to see a third FYA signal on the far left mast, but I get the feeling such signals are not so common in Kansas.
I appreciate that people continue to keep their eye out for these.
Oh yeah, there's another nearby: https://goo.gl/maps/W2sBPjURFyENcZyJ6
What's weird about that intersection, though, is the other direction of Strang Line Road has a protected-only signal for a single left turn: https://goo.gl/maps/gXdAG3YogLu2DRhm9
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 21, 2021, 12:30:53 PM
Post by: jakeroot on July 21, 2021, 12:30:53 PM
Quote from: stridentweasel on July 21, 2021, 06:42:55 AMQuote from: jakeroot on July 02, 2021, 01:57:17 PMQuote from: stridentweasel on July 01, 2021, 06:46:50 PM
I finally saw a modern local one, complete with FYAs: https://goo.gl/maps/cHRTRxb4Y68qZs5Q6
Nice find! Would have loved to see a third FYA signal on the far left mast, but I get the feeling such signals are not so common in Kansas.
I appreciate that people continue to keep their eye out for these.
Oh yeah, there's another nearby: https://goo.gl/maps/W2sBPjURFyENcZyJ6
What's weird about that intersection, though, is the other direction of Strang Line Road has a protected-only signal for a single left turn: https://goo.gl/maps/gXdAG3YogLu2DRhm9
Another good find, very cool!
I've definitely seen that setup before, with a double permissive left opposing a single lane protected-only left. Pretty much all have been for one of three reasons: (1) military base gate (https://goo.gl/maps/RsuKYpdSeyvG5SDw9); (2) poor visibility (maybe the reason here?); (3) not enough room to accommodate both directions waiting simultaneously (very rare -- cannot recall examples off the top of my head).
Title: Re: Double left turns with permissive phasing
Post by: mrsman on July 21, 2021, 10:07:02 PM
Post by: mrsman on July 21, 2021, 10:07:02 PM
Quote from: jakeroot on July 21, 2021, 12:30:53 PMQuote from: stridentweasel on July 21, 2021, 06:42:55 AMQuote from: jakeroot on July 02, 2021, 01:57:17 PMQuote from: stridentweasel on July 01, 2021, 06:46:50 PM
I finally saw a modern local one, complete with FYAs: https://goo.gl/maps/cHRTRxb4Y68qZs5Q6
Nice find! Would have loved to see a third FYA signal on the far left mast, but I get the feeling such signals are not so common in Kansas.
I appreciate that people continue to keep their eye out for these.
Oh yeah, there's another nearby: https://goo.gl/maps/W2sBPjURFyENcZyJ6
What's weird about that intersection, though, is the other direction of Strang Line Road has a protected-only signal for a single left turn: https://goo.gl/maps/gXdAG3YogLu2DRhm9
Another good find, very cool!
I've definitely seen that setup before, with a double permissive left opposing a single lane protected-only left. Pretty much all have been for one of three reasons: (1) military base gate (https://goo.gl/maps/RsuKYpdSeyvG5SDw9); (2) poor visibility (maybe the reason here?); (3) not enough room to accommodate both directions waiting simultaneously (very rare -- cannot recall examples off the top of my head).
Another possibility may be signalization. Now, this is not so common or necessary any more where FYAs are used, but in some jurisdictions there may still be fear of yellow traps and perceived yellow traps.
Let's say that we are not using FYAs (or Dallas phasing or other mechanisms to avoid yellow trap). So if you signalize a lead-lag signal, the leading arrow must be a protected only turn, if the lagging arrow is permissive/protected, in order to avoid yellow trap. And when you have a situation like that, it is better to make the busier of the two lefts, the lagging left so that as many people as possible can turn left during the gaps in traffic.
Earlier, we established that for an option lane setting, it is far more desirable to signalize that as a permissive lagging left. This is because when there are three lanes, and the left lane turns left, the right lane goes straight, and the center lane is an option lane, it provides some assurance for drivers that if they are waiting in the option lane behind someone turning left -- there will be an opportunity to proceed before the end of the phase. The left turners can filter during the natural gaps, and of course the protected turn at the end will allow both straight and left folks the opportunity to proceed until the light turns red.
Now it is true that if you go back up this thread and you see the many examples of option lane arrangements with permissive phasing, they would primarily have a lagging left and they will also prohibit or restrict the opposing left. A restricted left is a leading left that only allows for a protected turn.
It seems like we only discussed this a few weeks ago. 19th and Sloat in San Francisco has a lagging, permissive, option lane arrangement for the eastbound to northbound left. Yet, there is a left turn bay for the westbound to southbound left -- a remnant of a once permitted turn before there was a double left in the opposite direction.
Let's say that SF (or Caltrans) decides that they want to reintroduce that westbound to southbound left. The best way to do it would be a leading protected-only left, so as to not impact the visibility of the eastbound to northbound turn and to not introduce a yellow trap at the intersection. And that would be a situation with a permissive double left, but a protected-only opposing single left.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on August 12, 2021, 03:18:15 AM
Post by: jakeroot on August 12, 2021, 03:18:15 AM
I'm starting to think these may actually rank as "relatively common" in New Mexico. Found two three four new examples today:
(1) Yale Blvd northbound to Gibson Blvd westbound (https://goo.gl/maps/HDqKKu2PU2iVjkf1A) (alt view (https://goo.gl/maps/psepNqSAisijdh2EA))
(2) University Blvd northbound to Rio Bravo Blvd westbound (https://goo.gl/maps/YJthQKjq18wDRa7k8) (no opposing left)
(3) Carlisle Blvd northbound to Montgomery Blvd westbound (https://goo.gl/maps/pghFfuoM6uhfsr647) (alt view (https://goo.gl/maps/qX9bpEq13BvTAvCf9))
(4) NM-556 westbound at I-25 southbound on-ramp (https://goo.gl/maps/yDbyipZKk2yYrNW38) (FYA) (formerly protected-only)
The second was formerly protected-only (https://goo.gl/maps/vbCz2SiP5Yj7auVs9). Seems to operate with lagging phasing, based on this still (https://goo.gl/maps/hZSuREaGC1qLszGU8).
The third has an opposing single-lane protected-only left turn. Go figure, given the discussion above. The left turn seems to be leading, so I'm not sure the purpose of the opposing protection.
(1) Yale Blvd northbound to Gibson Blvd westbound (https://goo.gl/maps/HDqKKu2PU2iVjkf1A) (alt view (https://goo.gl/maps/psepNqSAisijdh2EA))
(2) University Blvd northbound to Rio Bravo Blvd westbound (https://goo.gl/maps/YJthQKjq18wDRa7k8) (no opposing left)
(3) Carlisle Blvd northbound to Montgomery Blvd westbound (https://goo.gl/maps/pghFfuoM6uhfsr647) (alt view (https://goo.gl/maps/qX9bpEq13BvTAvCf9))
(4) NM-556 westbound at I-25 southbound on-ramp (https://goo.gl/maps/yDbyipZKk2yYrNW38) (FYA) (formerly protected-only)
The second was formerly protected-only (https://goo.gl/maps/vbCz2SiP5Yj7auVs9). Seems to operate with lagging phasing, based on this still (https://goo.gl/maps/hZSuREaGC1qLszGU8).
The third has an opposing single-lane protected-only left turn. Go figure, given the discussion above. The left turn seems to be leading, so I'm not sure the purpose of the opposing protection.
Title: Re: Double left turns with permissive phasing
Post by: US 89 on August 12, 2021, 08:30:22 AM
Post by: US 89 on August 12, 2021, 08:30:22 AM
I encountered one the other day from Dewar Drive eastbound to Gateway Blvd in Rock Springs, WY. First one I’d ever seen in Wyoming.
https://goo.gl/maps/6d1NqeFpcFGhXQjr6
https://goo.gl/maps/6d1NqeFpcFGhXQjr6
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on August 12, 2021, 12:25:03 PM
Post by: jakeroot on August 12, 2021, 12:25:03 PM
Quote from: US 89 on August 12, 2021, 08:30:22 AM
I encountered one the other day from Dewar Drive eastbound to Gateway Blvd in Rock Springs, WY. First one I'd ever seen in Wyoming.
https://goo.gl/maps/6d1NqeFpcFGhXQjr6
Same here, never seen one in Wyoming.
Virtually zero historic Street View imagery, but it looks to have been installed around 2008 or 2009.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on August 13, 2021, 10:16:14 PM
Post by: jakeroot on August 13, 2021, 10:16:14 PM
Quote from: jakeroot on August 12, 2021, 12:25:03 PMQuote from: US 89 on August 12, 2021, 08:30:22 AM
I encountered one the other day from Dewar Drive eastbound to Gateway Blvd in Rock Springs, WY. First one I'd ever seen in Wyoming.
https://goo.gl/maps/6d1NqeFpcFGhXQjr6
Same here, never seen one in Wyoming.
Virtually zero historic Street View imagery, but it looks to have been installed around 2008 or 2009.
Down the road, I actually found another example using a double side-by-side 5-section signals (similar to those used in Colorado), complete with a "left turn yield on green" sign:
https://goo.gl/maps/yX5vbovGh2yNgQvs8
Couple other interesting things about this intersection:
* there is no pedestrian signal for the southeast-to-southwest crossing
* flashing yellow arrows are used for Dewer Dr but not the double left turn (as they shouldn't since it's a shared left/straight/right lane)
* the opposing approach uses only post-mounted signals
Title: Re: Double left turns with permissive phasing
Post by: bcroadguy on August 14, 2021, 04:33:25 AM
Post by: bcroadguy on August 14, 2021, 04:33:25 AM
Interestingly, 2007 Streetview has a pedestrian signal there, but it was removed at some point.
Having a pedestrian signal on one side of a crosswalk but not the other is very strange.
Having a pedestrian signal on one side of a crosswalk but not the other is very strange.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on August 14, 2021, 01:36:40 PM
Post by: jakeroot on August 14, 2021, 01:36:40 PM
Quote from: bcroadguy on August 14, 2021, 04:33:25 AM
Interestingly, 2007 Streetview has a pedestrian signal there, but it was removed at some point.
Having a pedestrian signal on one side of a crosswalk but not the other is very strange.
Looking again, it does seem that GSV may have passed through mid-construction. There are no sidewalks anywhere, but there was in older imagery. This tells me that they were in the process of installing the new pedestrian equipment? Maybe. I would hope so, as there was a pedestrian signal on that corner before.
Title: Re: Double left turns with permissive phasing
Post by: Roadwarriors79 on August 25, 2021, 05:49:27 AM
Post by: Roadwarriors79 on August 25, 2021, 05:49:27 AM
Lake Pleasant Pkwy at Loop 303 in Peoria. If the area near the intersection was more developed, the left turns would probably be fully protected lefts.
SM-G998U1
SM-G998U1
Title: Re: Double left turns with permissive phasing
Post by: kphoger on August 25, 2021, 12:43:55 PM
Post by: kphoger on August 25, 2021, 12:43:55 PM
Quote from: Roadwarriors79 on August 25, 2021, 05:49:27 AM
Lake Pleasant Pkwy at Loop 303 in Peoria. If the area near the intersection was more developed, the left turns would probably be fully protected lefts.
GSV here (https://goo.gl/maps/qvyiByyN8hzi5uF87), in case anyone else, like me, didn't know at first what state you were even talking about.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on November 15, 2021, 11:15:46 AM
Post by: fwydriver405 on November 15, 2021, 11:15:46 AM
Saw a true double permissive FYA left with lead-lag without LPI, and dual split lag with an LPI and FYA overlap inhibit after the Portland Trailblazers at Denver Nuggets game at Ball Arena in Denver CO yesterday. Based on looking at GSV it also may appear that the FYA's run TOD phasing, omitting the permissive phase at certain times of the day. Surely something you don't see back east!
I know it's been discussed earlier in this forum, but how abundant are double permissive lefts in CO, either with circular green or flashing yellow arrow?
Location of the intersection at Ball Arena (https://www.google.com/maps/place/39%C2%B045'00.5%22N+105%C2%B000'17.5%22W/@39.7502078,-105.005236,18.21z/data=!4m5!3m4!1s0x0:0x9ffa3af20c0ed580!8m2!3d39.7501469!4d-105.0048521)
https://www.youtube.com/watch?v=RVqw1BuaXwY
I know it's been discussed earlier in this forum, but how abundant are double permissive lefts in CO, either with circular green or flashing yellow arrow?
Location of the intersection at Ball Arena (https://www.google.com/maps/place/39%C2%B045'00.5%22N+105%C2%B000'17.5%22W/@39.7502078,-105.005236,18.21z/data=!4m5!3m4!1s0x0:0x9ffa3af20c0ed580!8m2!3d39.7501469!4d-105.0048521)
https://www.youtube.com/watch?v=RVqw1BuaXwY
Title: Re: Double left turns with permissive phasing
Post by: Big John on November 15, 2021, 12:26:19 PM
Post by: Big John on November 15, 2021, 12:26:19 PM
Green Bay just changed the signals on Military Ave. and Mason St. from a lead-lag dual left turn lanes with turn on arrow only to lead-only FYA signals in both lanes in both directions. The main complaint was that the green arrows did not stay green long enough.
Title: Re: Double left turns with permissive phasing
Post by: zachary_amaryllis on December 14, 2021, 11:56:53 AM
Post by: zachary_amaryllis on December 14, 2021, 11:56:53 AM
a slight thread bump, but a question about the blinky arrows. this is an example of both a double-permissive, and a FYA. what i do not understand, is this light is never green, even though green lights exist on the heads. every time you're at this intersection, you get the blinky arrows.
there are a couple other examples of similar signals in fort collins, that work the same way. my first guess was a pedestrian conflict, but regardless of the state of the pedestrian signals, its always fya (or red). driveways of businesses maybe? there's a lot of them on north college. if you pan the picture around a little, you can see the 'don't walk' light lit. it could be blinking at the time this picture was taken, but no matter. you never get a green left arrow.
wasn't sure if this belonged here or the fya thread, since it talks about both. so if its better there, feel free to move it.
https://goo.gl/maps/rY2ucbHqntPGq8916 (https://goo.gl/maps/rY2ucbHqntPGq8916)
note car running red light.
there are a couple other examples of similar signals in fort collins, that work the same way. my first guess was a pedestrian conflict, but regardless of the state of the pedestrian signals, its always fya (or red). driveways of businesses maybe? there's a lot of them on north college. if you pan the picture around a little, you can see the 'don't walk' light lit. it could be blinking at the time this picture was taken, but no matter. you never get a green left arrow.
wasn't sure if this belonged here or the fya thread, since it talks about both. so if its better there, feel free to move it.
https://goo.gl/maps/rY2ucbHqntPGq8916 (https://goo.gl/maps/rY2ucbHqntPGq8916)
note car running red light.
Title: Re: Double left turns with permissive phasing
Post by: jeffandnicole on December 14, 2021, 12:16:10 PM
Post by: jeffandnicole on December 14, 2021, 12:16:10 PM
Quote from: zachary_amaryllis on December 14, 2021, 11:56:53 AM
a slight thread bump, but a question about the blinky arrows. this is an example of both a double-permissive, and a FYA. what i do not understand, is this light is never green, even though green lights exist on the heads. every time you're at this intersection, you get the blinky arrows.
there are a couple other examples of similar signals in fort collins, that work the same way. my first guess was a pedestrian conflict, but regardless of the state of the pedestrian signals, its always fya (or red). driveways of businesses maybe? there's a lot of them on north college. if you pan the picture around a little, you can see the 'don't walk' light lit. it could be blinking at the time this picture was taken, but no matter. you never get a green left arrow.
wasn't sure if this belonged here or the fya thread, since it talks about both. so if its better there, feel free to move it.
https://goo.gl/maps/rY2ucbHqntPGq8916 (https://goo.gl/maps/rY2ucbHqntPGq8916)
note car running red light.
Car didn't run red light. Go back a little and you'll see the light was still yellow when he was past the stop line turning.
Title: Re: Double left turns with permissive phasing
Post by: roadman65 on December 14, 2021, 12:25:41 PM
Post by: roadman65 on December 14, 2021, 12:25:41 PM
Quote from: zachary_amaryllis on December 14, 2021, 11:56:53 AM
a slight thread bump, but a question about the blinky arrows. this is an example of both a double-permissive, and a FYA. what i do not understand, is this light is never green, even though green lights exist on the heads. every time you're at this intersection, you get the blinky arrows.
there are a couple other examples of similar signals in fort collins, that work the same way. my first guess was a pedestrian conflict, but regardless of the state of the pedestrian signals, its always fya (or red). driveways of businesses maybe? there's a lot of them on north college. if you pan the picture around a little, you can see the 'don't walk' light lit. it could be blinking at the time this picture was taken, but no matter. you never get a green left arrow.
wasn't sure if this belonged here or the fya thread, since it talks about both. so if its better there, feel free to move it.
https://goo.gl/maps/rY2ucbHqntPGq8916 (https://goo.gl/maps/rY2ucbHqntPGq8916)
note car running red light.
Watch Welcome Back Kotter on DVD or Hulu and the final season openers show the car filming the drive under the elevated subway drives through a red light.
To support Jeff and Nicole.
https://goo.gl/maps/UdxnneyaY1HPEnJ39
Title: Re: Double left turns with permissive phasing
Post by: mrsman on December 22, 2021, 10:03:27 AM
Post by: mrsman on December 22, 2021, 10:03:27 AM
Quote from: mrsman on March 30, 2020, 12:50:08 AMQuote from: jakeroot on March 28, 2020, 04:27:40 AMQuote from: jakeroot on February 24, 2020, 03:13:05 PM
Found another in Chicago: https://goo.gl/maps/Zn42Wji2djFMVPdd9
This brings the Chicago area tothreefour known installations:
N Sheridan Road @ W Bryn Mawr Ave (https://goo.gl/maps/8DEpRwMKMZ8tc3EK7) (option lane)
N Columbus Drive (NB) @ E Grand Ave (https://goo.gl/maps/Zn42Wji2djFMVPdd9) (former option lane, now two dedicated turns)(NEW)
N Columbus Drive (SB) @ E Illinois Street (https://goo.gl/maps/Zu7i8GP8ij2q6kKg9) (former option lane, now two dedicated turns)(NEW)
Thorndale Ave @ Park Blvd, Itasca (https://goo.gl/maps/SZSFA9SQdQVQ5JJM9) (true double left) (removed, now an off-ramp from the 390 Toll Road)
Found more in Chicago. Both seem to be a fairly central area, so I'm definitely surprised someone hasn't mentioned either:
E Jackson Drive (WB) @ S Columbus Drive (https://goo.gl/maps/nY11a5j7tpGHMycU7) (option lane) (NEW)
E Monroe Street (EB) @ LSD (https://goo.gl/maps/y8LPBSbbDavLT6659) (two dedicated turn lanes) (NEW) (no protected phase)
Chicago has quickly become #1 among largest US cities! Of the ten largest cities, those in Texas might have some onto frontage roads, but these are so damn common I don't feel like including them on this list. Really not until you get towards Seattle or Denver, do you get cities with at least a couple of known installations (Denver having quite a few, Seattle having less than in the past). Eventually, down at #34, is Tucson, which is still reigning champ AFAIK.
Monroe/LSD is against a driveway from a Yacht Club. while still a double permissive turn, given that it is a private driveway, it is unlikely to get too much traffic.
I.e. aside from a small amount of driveway traffic, this is essentially a T-intersection.
When developing a fictional idea for Chicago in the Fictional thread, I stumbled across this intersection in Chicago:
https://www.google.com/maps/@41.9854845,-87.6601596,3a,75y,173.78h,83.64t/data=!3m6!1e1!3m4!1sKNDU36-2SYD7WIt981cncw!2e0!7i16384!8i8192
Broadway at Hollywood, with an option lane. A few blocks from the north end of LSD. A few blocks from Sheridan/Bryn Mawr which is mentioned upthread.
[I don't think this was mentioned upthread, I searched.]
Title: Re: Double left turns with permissive phasing
Post by: JayhawkCO on December 29, 2021, 11:08:01 AM
Post by: JayhawkCO on December 29, 2021, 11:08:01 AM
Quote from: jakeroot on July 21, 2021, 12:30:53 PMQuote from: stridentweasel on July 21, 2021, 06:42:55 AMQuote from: jakeroot on July 02, 2021, 01:57:17 PMQuote from: stridentweasel on July 01, 2021, 06:46:50 PM
I finally saw a modern local one, complete with FYAs: https://goo.gl/maps/cHRTRxb4Y68qZs5Q6
Nice find! Would have loved to see a third FYA signal on the far left mast, but I get the feeling such signals are not so common in Kansas.
I appreciate that people continue to keep their eye out for these.
Oh yeah, there's another nearby: https://goo.gl/maps/W2sBPjURFyENcZyJ6
What's weird about that intersection, though, is the other direction of Strang Line Road has a protected-only signal for a single left turn: https://goo.gl/maps/gXdAG3YogLu2DRhm9
Another good find, very cool!
I've definitely seen that setup before, with a double permissive left opposing a single lane protected-only left. Pretty much all have been for one of three reasons: (1) military base gate (https://goo.gl/maps/RsuKYpdSeyvG5SDw9); (2) poor visibility (maybe the reason here?); (3) not enough room to accommodate both directions waiting simultaneously (very rare -- cannot recall examples off the top of my head).
I know there's lots of CO examples, but here is another one I drove through yesterday (https://www.google.com/maps/@39.5948762,-104.7873499,3a,75y,46.34h,90.26t/data=!3m6!1e1!3m4!1sH0jEpgbxLtS505q_JlYIEg!2e0!7i16384!8i8192) just south of my house. Had never really paid attention before.
Title: Re: Double left turns with permissive phasing
Post by: zachary_amaryllis on December 29, 2021, 03:39:26 PM
Post by: zachary_amaryllis on December 29, 2021, 03:39:26 PM
https://www.google.com/maps/place/US-287,+Fort+Collins,+CO+80524/@40.5922395,-105.0769961,3a,75y,206.42h,90t/data=!3m4!1e1!3m2!1suO1ZmZ-3vQCidlc4hDk3zA!2e0!4m2!3m1!1s0x87694a8988660905:0x551117780965d34f (https://www.google.com/maps/place/US-287,+Fort+Collins,+CO+80524/@40.5922395,-105.0769961,3a,75y,206.42h,90t/data=!3m4!1e1!3m2!1suO1ZmZ-3vQCidlc4hDk3zA!2e0!4m2!3m1!1s0x87694a8988660905:0x551117780965d34f)
example from fort collins if i did this right. college/cherry
example from fort collins if i did this right. college/cherry
Title: Re: Double left turns with permissive phasing
Post by: ran4sh on December 29, 2021, 06:37:03 PM
Post by: ran4sh on December 29, 2021, 06:37:03 PM
The problem with permissive left turns on major arterial or expressway roadways is, drivers are used to being able to shift the path of their turn right (e.g. greater arc radius) or left (lesser arc radius) as necessary to fit through gaps in traffic, which is not a problem with single lane left turns, but obviously if a driver shifted right from the left turn lane or left from the right side left turn lane then they would interfere with the path of other vehicles.
Maybe this isn't a problem in low speed conditions but I wouldn't agree with allowing it in general.
Maybe this isn't a problem in low speed conditions but I wouldn't agree with allowing it in general.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on January 02, 2022, 09:30:20 AM
Post by: fwydriver405 on January 02, 2022, 09:30:20 AM
Don't know if this counts, but on my way down to Woodbridge Twp NJ, I saw a double permissive left for a concurrent pedestrian phase in Jersey City NJ (Location (https://www.google.com/maps/@40.7303773,-74.0413413,149m/data=!3m1!1e3)). I think the entirety of the origin street I was on was one way, so that's why I question it. I believe the protected phase comes on at the end after the pedestrian phase ends.
https://youtu.be/ruv6SQare30
https://youtu.be/ruv6SQare30
Title: Re: Double left turns with permissive phasing
Post by: Hobart on February 05, 2022, 02:18:11 AM
Post by: Hobart on February 05, 2022, 02:18:11 AM
Hopefully this doesn't constitute bumping a dead thread.
I found an example in British Columbia of all places, while doom scrolling in google maps.
https://www.google.com/maps/@49.1701299,-123.1590777,3a,45.8y,88.6h,95.48t/data=!3m6!1e1!3m4!1stxlaglUEbke6Sdamf622MQ!2e0!7i16384!8i8192
I found an example in British Columbia of all places, while doom scrolling in google maps.
https://www.google.com/maps/@49.1701299,-123.1590777,3a,45.8y,88.6h,95.48t/data=!3m6!1e1!3m4!1stxlaglUEbke6Sdamf622MQ!2e0!7i16384!8i8192
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 05, 2022, 01:28:41 PM
Post by: jakeroot on February 05, 2022, 01:28:41 PM
Quote from: Hobart on February 05, 2022, 02:18:11 AM
Hopefully this doesn't constitute bumping a dead thread.
I found an example in British Columbia of all places, while doom scrolling in google maps.
https://www.google.com/maps/@49.1701299,-123.1590777,3a,45.8y,88.6h,95.48t/data=!3m6!1e1!3m4!1stxlaglUEbke6Sdamf622MQ!2e0!7i16384!8i8192
Yeah, rare example! Richmond actually has a couple more examples, one on the other side of the No. 2 Road Bridge (here (https://goo.gl/maps/6wmJGfeFujJ6pacu8)), and another leaving the cell phone lot at YVR (here (https://goo.gl/maps/gfb6nGUNkBGieLaL8)).
I actually have a video of the example you linked to. They've since replaced all of the signals with 12-inch lenses (seen here (https://goo.gl/maps/VrrPQy7DhFpNcVLo8)), so they are evidently committed to the permissive phasing:
https://youtu.be/65MP7m4qTtA
Title: Re: Double left turns with permissive phasing
Post by: Revive 755 on February 08, 2022, 11:04:42 PM
Post by: Revive 755 on February 08, 2022, 11:04:42 PM
Based on Page 11 of 26 of these plans (https://apps.dot.illinois.gov/eplan/desenv/031122/028-64M24/PLANS/PL-64M24-028.pdf), a permissive dual left may be available for eastbound at the IL 92/Centennial Expressway/Andalusiaa Road intersection near Rock Island when a train blocks the south leg ("EBLT shall flash yellow during dwell").
Title: Re: Double left turns with permissive phasing
Post by: Hobart on February 12, 2022, 02:05:19 AM
Post by: Hobart on February 12, 2022, 02:05:19 AM
I found another example in New Mexico while doom scrolling at 1 AM.
https://www.google.com/maps/@32.8998397,-105.9602423,3a,66y,267.19h,93.23t/data=!3m6!1e1!3m4!1sz1ImLXsZWwh6ujNRF6uOQg!2e0!7i16384!8i8192
This one's interesting to me because there's only one overhead five segment signal for a total of four lanes of traffic.
https://www.google.com/maps/@32.8998397,-105.9602423,3a,66y,267.19h,93.23t/data=!3m6!1e1!3m4!1sz1ImLXsZWwh6ujNRF6uOQg!2e0!7i16384!8i8192
This one's interesting to me because there's only one overhead five segment signal for a total of four lanes of traffic.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 28, 2022, 01:52:26 PM
Post by: jakeroot on February 28, 2022, 01:52:26 PM
Quote from: Revive 755 on February 08, 2022, 11:04:42 PM
Based on Page 11 of 26 of these plans (https://apps.dot.illinois.gov/eplan/desenv/031122/028-64M24/PLANS/PL-64M24-028.pdf), a permissive dual left may be available for eastbound at the IL 92/Centennial Expressway/Andalusiaa Road intersection near Rock Island when a train blocks the south leg ("EBLT shall flash yellow during dwell").
I can see in real life that only the green section is an arrow. So would it flash yellow for the EBLT, solid green for through, and red for WBLT? Interesting.
Quote from: Hobart on February 12, 2022, 02:05:19 AM
I found another example in New Mexico while doom scrolling at 1 AM.
https://www.google.com/maps/@32.8998397,-105.9602423,3a,66y,267.19h,93.23t/data=!3m6!1e1!3m4!1sz1ImLXsZWwh6ujNRF6uOQg!2e0!7i16384!8i8192
This one's interesting to me because there's only one overhead five segment signal for a total of four lanes of traffic.
Doubly interesting (no pun intending) because there is no supplemental left turn signal on the far left corner. That's typically standard in New Mexico, especially at double left turns. Well, at least with it being permissive, the overhead and supplemental right corner signal technically mean the signal meets the two-signal minimum rule.
I will add that New Mexico has a surprisingly high number of permissive double left turns. I think they're in the top five, perhaps behind only Colorado and Texas.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 28, 2022, 01:55:44 PM
Post by: jakeroot on February 28, 2022, 01:55:44 PM
Neglecting this thread, reviving it with a question for Michiganders.
At the newly rebuilt Telegraph Rd / Plymouth Rd intersection in Detroit, the southbound-to-northbound U-turn intersects a minor road, and both the double U-turn and minor street receive green signals. Would traffic turning left (making a U-turn, technically) be required to yield to anyone on that road? My gut says absolutely, as both approaches receive simultaneous green orbs (as I mentioned), and I see no other signs indicating to the contrary.
https://goo.gl/maps/mtbxiUpt7AvJwvZM6 (view #1)
https://goo.gl/maps/DnQf4iVCLwnNu2Qv6 (view #2)
At the newly rebuilt Telegraph Rd / Plymouth Rd intersection in Detroit, the southbound-to-northbound U-turn intersects a minor road, and both the double U-turn and minor street receive green signals. Would traffic turning left (making a U-turn, technically) be required to yield to anyone on that road? My gut says absolutely, as both approaches receive simultaneous green orbs (as I mentioned), and I see no other signs indicating to the contrary.
https://goo.gl/maps/mtbxiUpt7AvJwvZM6 (view #1)
https://goo.gl/maps/DnQf4iVCLwnNu2Qv6 (view #2)
Title: Re: Double left turns with permissive phasing
Post by: ran4sh on March 01, 2022, 11:38:33 AM
Post by: ran4sh on March 01, 2022, 11:38:33 AM
I have no experience with Michigan but it appears to me that such traffic would indeed have to yield, but that is such a minor street that u-turning traffic is unlikely to encounter opposing traffic.
Plus both approaches are able to make their respective turns on red as far as I know (the U-turn part of the Michigan Left maneuver is counted as a left turn from one-way to one-way).
Plus both approaches are able to make their respective turns on red as far as I know (the U-turn part of the Michigan Left maneuver is counted as a left turn from one-way to one-way).
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 01, 2022, 06:22:00 PM
Post by: jakeroot on March 01, 2022, 06:22:00 PM
Quote from: ran4sh on March 01, 2022, 11:38:33 AM
I have no experience with Michigan but it appears to me that such traffic would indeed have to yield, but that is such a minor street that u-turning traffic is unlikely to encounter opposing traffic.
Plus both approaches are able to make their respective turns on red as far as I know (the U-turn part of the Michigan Left maneuver is counted as a left turn from one-way to one-way).
Agreed with that assessment, I suspect it wasn't worth split-phasing. Although it's got me wondering how common such a setup is.
Title: Re: Double left turns with permissive phasing
Post by: Hobart on March 13, 2022, 09:23:17 PM
Post by: Hobart on March 13, 2022, 09:23:17 PM
I found a very interesting example at a Minnesota intersection.
https://www.google.com/maps/@44.8522878,-93.1298118,3a,75.1y,250.94h,94.73t/data=!3m6!1e1!3m4!1sTNJBDnUyDGyaQZwzYj-JVw!2e0!7i16384!8i8192
One approach has normal double flashing yellow arrows for a two-lane wide permissive setup.
The more interesting approach has one flashing yellow arrow above the left turn lane, and Minnesota's flashing yellow arrow weird doghouse signal permissive left turn thing above the option lane. This is the only time I've seen these two signals used on the same mast arm for the same approach.
https://www.google.com/maps/@44.8522878,-93.1298118,3a,75.1y,250.94h,94.73t/data=!3m6!1e1!3m4!1sTNJBDnUyDGyaQZwzYj-JVw!2e0!7i16384!8i8192
One approach has normal double flashing yellow arrows for a two-lane wide permissive setup.
The more interesting approach has one flashing yellow arrow above the left turn lane, and Minnesota's flashing yellow arrow weird doghouse signal permissive left turn thing above the option lane. This is the only time I've seen these two signals used on the same mast arm for the same approach.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 15, 2022, 11:35:28 AM
Post by: jakeroot on March 15, 2022, 11:35:28 AM
Quote from: Hobart on March 13, 2022, 09:23:17 PM
I found a very interesting example at a Minnesota intersection.
https://www.google.com/maps/@44.8522878,-93.1298118,3a,75.1y,250.94h,94.73t/data=!3m6!1e1!3m4!1sTNJBDnUyDGyaQZwzYj-JVw!2e0!7i16384!8i8192
One approach has normal double flashing yellow arrows for a two-lane wide permissive setup.
The more interesting approach has one flashing yellow arrow above the left turn lane, and Minnesota's flashing yellow arrow weird doghouse signal permissive left turn thing above the option lane. This is the only time I've seen these two signals used on the same mast arm for the same approach.
There is one other identical approach in Eden Prairie as well: https://goo.gl/maps/AB3ktBEx8e15CDka7
I guess a good term for this kind of setup, given that there is apparently more than a couple of them in the state, is the "Minnesota-style option lane double permissive turn"...maybe someone can think of something catchier.
Title: Re: Double left turns with permissive phasing
Post by: Hobart on March 24, 2022, 12:03:43 AM
Post by: Hobart on March 24, 2022, 12:03:43 AM
Quote from: jakeroot on March 15, 2022, 11:35:28 AMQuote from: Hobart on March 13, 2022, 09:23:17 PM
I found a very interesting example at a Minnesota intersection.
https://www.google.com/maps/@44.8522878,-93.1298118,3a,75.1y,250.94h,94.73t/data=!3m6!1e1!3m4!1sTNJBDnUyDGyaQZwzYj-JVw!2e0!7i16384!8i8192
One approach has normal double flashing yellow arrows for a two-lane wide permissive setup.
The more interesting approach has one flashing yellow arrow above the left turn lane, and Minnesota's flashing yellow arrow weird doghouse signal permissive left turn thing above the option lane. This is the only time I've seen these two signals used on the same mast arm for the same approach.
There is one other identical approach in Eden Prairie as well: https://goo.gl/maps/AB3ktBEx8e15CDka7
I guess a good term for this kind of setup, given that there is apparently more than a couple of them in the state, is the "Minnesota-style option lane double permissive turn"...maybe someone can think of something catchier.
There is definitely more than a couple!
I found a third one in Elk River.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 24, 2022, 02:00:22 PM
Post by: jakeroot on March 24, 2022, 02:00:22 PM
Quote from: Hobart on March 24, 2022, 12:03:43 AMQuote from: jakeroot on March 15, 2022, 11:35:28 AMQuote from: Hobart on March 13, 2022, 09:23:17 PM
I found a very interesting example at a Minnesota intersection.
https://www.google.com/maps/@44.8522878,-93.1298118,3a,75.1y,250.94h,94.73t/data=!3m6!1e1!3m4!1sTNJBDnUyDGyaQZwzYj-JVw!2e0!7i16384!8i8192
One approach has normal double flashing yellow arrows for a two-lane wide permissive setup.
The more interesting approach has one flashing yellow arrow above the left turn lane, and Minnesota's flashing yellow arrow weird doghouse signal permissive left turn thing above the option lane. This is the only time I've seen these two signals used on the same mast arm for the same approach.
There is one other identical approach in Eden Prairie as well: https://goo.gl/maps/AB3ktBEx8e15CDka7
I guess a good term for this kind of setup, given that there is apparently more than a couple of them in the state, is the "Minnesota-style option lane double permissive turn"...maybe someone can think of something catchier.
There is definitely more than a couple!
I found a third one in Elk River.
Could you indicate where? I glanced around but didn't see any specific locations with the option-lane double permissive left turn setup like the two just mentioned.
Title: Re: Double left turns with permissive phasing
Post by: Hobart on March 24, 2022, 05:23:21 PM
Post by: Hobart on March 24, 2022, 05:23:21 PM
Quote from: jakeroot on March 24, 2022, 02:00:22 PMQuote from: Hobart on March 24, 2022, 12:03:43 AMQuote from: jakeroot on March 15, 2022, 11:35:28 AMQuote from: Hobart on March 13, 2022, 09:23:17 PM
I found a very interesting example at a Minnesota intersection.
https://www.google.com/maps/@44.8522878,-93.1298118,3a,75.1y,250.94h,94.73t/data=!3m6!1e1!3m4!1sTNJBDnUyDGyaQZwzYj-JVw!2e0!7i16384!8i8192
One approach has normal double flashing yellow arrows for a two-lane wide permissive setup.
The more interesting approach has one flashing yellow arrow above the left turn lane, and Minnesota's flashing yellow arrow weird doghouse signal permissive left turn thing above the option lane. This is the only time I've seen these two signals used on the same mast arm for the same approach.
There is one other identical approach in Eden Prairie as well: https://goo.gl/maps/AB3ktBEx8e15CDka7
I guess a good term for this kind of setup, given that there is apparently more than a couple of them in the state, is the "Minnesota-style option lane double permissive turn"...maybe someone can think of something catchier.
There is definitely more than a couple!
I found a third one in Elk River.
Could you indicate where? I glanced around but didn't see any specific locations with the option-lane double permissive left turn setup like the two just mentioned.
So, this is what happens when I don't proofread my own posts because I post too late at night.
https://www.google.com/maps/@45.3077572,-93.5774317,3a,75y,184.13h,90t/data=!3m7!1e1!3m5!1skLHdqbvOPrTIFWd3Mw33dg!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DkLHdqbvOPrTIFWd3Mw33dg%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D182.91048%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192
Sorry for the runaround.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 24, 2022, 08:45:30 PM
Post by: jakeroot on March 24, 2022, 08:45:30 PM
Quote from: Hobart on March 24, 2022, 05:23:21 PMQuote from: jakeroot on March 24, 2022, 02:00:22 PMQuote from: Hobart on March 24, 2022, 12:03:43 AMQuote from: jakeroot on March 15, 2022, 11:35:28 AMQuote from: Hobart on March 13, 2022, 09:23:17 PM
I found a very interesting example at a Minnesota intersection.
https://www.google.com/maps/@44.8522878,-93.1298118,3a,75.1y,250.94h,94.73t/data=!3m6!1e1!3m4!1sTNJBDnUyDGyaQZwzYj-JVw!2e0!7i16384!8i8192
One approach has normal double flashing yellow arrows for a two-lane wide permissive setup.
The more interesting approach has one flashing yellow arrow above the left turn lane, and Minnesota's flashing yellow arrow weird doghouse signal permissive left turn thing above the option lane. This is the only time I've seen these two signals used on the same mast arm for the same approach.
There is one other identical approach in Eden Prairie as well: https://goo.gl/maps/AB3ktBEx8e15CDka7
I guess a good term for this kind of setup, given that there is apparently more than a couple of them in the state, is the "Minnesota-style option lane double permissive turn"...maybe someone can think of something catchier.
There is definitely more than a couple!
I found a third one in Elk River.
Could you indicate where? I glanced around but didn't see any specific locations with the option-lane double permissive left turn setup like the two just mentioned.
So, this is what happens when I don't proofread my own posts because I post too late at night.
https://www.google.com/maps/@45.3077572,-93.5774317,3a,75y,184.13h,90t/data=!3m7!1e1!3m5!1skLHdqbvOPrTIFWd3Mw33dg!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DkLHdqbvOPrTIFWd3Mw33dg%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D182.91048%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192
Sorry for the runaround.
All good! Thanks for sharing that. No wonder I didn't spot it while browsing overhead, it was just installed and not shown on globe satellite view. Although it is shown on non-globe satellite view...note to self, turn off globe satellite mode when looking for most recent imagery!
In terms of the setup, it seems like there may be some path overlap. I'm curious when it's set to operate, I'm able to see GSV imagery showing it operating, but it's operating more as a split-phase intersection.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 25, 2022, 02:06:07 PM
Post by: jakeroot on March 25, 2022, 02:06:07 PM
JMAN_WiS&S recently brought up Eau Claire, Wisconsin in another thread, and it reminded me to take a look around that place again.
I noticed that eastbound Clairemont to the northbound Hastings Way onramp has a double permissive left turn using flashing yellow arrows:
https://goo.gl/maps/n7DnBT2NXR9VsN1A9
In true Eau Claire fashion, there's plenty of signals! Unfortunately, I wasn't able to find any GSV of the left turn signals operating in permissive mode. If there are any locals that know of this intersections and could comment on how it operates, I'd love to know if it actually runs in permissive mode (perhaps at night).
I noticed that eastbound Clairemont to the northbound Hastings Way onramp has a double permissive left turn using flashing yellow arrows:
https://goo.gl/maps/n7DnBT2NXR9VsN1A9
In true Eau Claire fashion, there's plenty of signals! Unfortunately, I wasn't able to find any GSV of the left turn signals operating in permissive mode. If there are any locals that know of this intersections and could comment on how it operates, I'd love to know if it actually runs in permissive mode (perhaps at night).
Title: Re: Double left turns with permissive phasing
Post by: Hobart on March 26, 2022, 09:01:03 PM
Post by: Hobart on March 26, 2022, 09:01:03 PM
Quote from: jakeroot on March 25, 2022, 02:06:07 PM
JMAN_WiS&S recently brought up Eau Claire, Wisconsin in another thread, and it reminded me to take a look around that place again.
I noticed that eastbound Clairemont to the northbound Hastings Way onramp has a double permissive left turn using flashing yellow arrows:
https://goo.gl/maps/n7DnBT2NXR9VsN1A9
In true Eau Claire fashion, there's plenty of signals! Unfortunately, I wasn't able to find any GSV of the left turn signals operating in permissive mode. If there are any locals that know of this intersections and could comment on how it operates, I'd love to know if it actually runs in permissive mode (perhaps at night).
I wonder why Wisconsin insists on using so many heads for everything. I appreciate good supplementary heads, but this is getting ridiculous.
Also, although in a completely different place, I found a Mississippi setup that uses double doghouses... in the middle of the day, with both left turn directions going at the same time, at an intersection with US 90, completely unlike the example you just sent. Duaity of man I guess.
https://www.google.com/maps/@30.4161172,-88.8277286,3a,24.9y,173.78h,94.98t/data=!3m6!1e1!3m4!1sN1IQDLKTGHznubnJzg7iwA!2e0!7i16384!8i8192
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 27, 2022, 01:45:48 PM
Post by: jakeroot on March 27, 2022, 01:45:48 PM
Quote from: Hobart on March 26, 2022, 09:01:03 PMQuote from: jakeroot on March 25, 2022, 02:06:07 PM
JMAN_WiS&S recently brought up Eau Claire, Wisconsin in another thread, and it reminded me to take a look around that place again.
I noticed that eastbound Clairemont to the northbound Hastings Way onramp has a double permissive left turn using flashing yellow arrows:
https://goo.gl/maps/n7DnBT2NXR9VsN1A9
In true Eau Claire fashion, there's plenty of signals! Unfortunately, I wasn't able to find any GSV of the left turn signals operating in permissive mode. If there are any locals that know of this intersections and could comment on how it operates, I'd love to know if it actually runs in permissive mode (perhaps at night).
I wonder why Wisconsin insists on using so many heads for everything. I appreciate good supplementary heads, but this is getting ridiculous.
Actually, the new standard for Wisconsin is all overhead with one nearside signal for each maneuver, which is not really that impressive. Even most Illinois districts require both one nearside signal and one far left corner signal. Eau Claire, on the other hand, goes a bit above and beyond, looking more like California or Nevada with their new installations compared to the rest of Wisconsin.
Quote from: Hobart on March 26, 2022, 09:01:03 PM
Also, although in a completely different place, I found a Mississippi setup that uses double doghouses... in the middle of the day, with both left turn directions going at the same time, at an intersection with US 90, completely unlike the example you just sent. Duaity of man I guess.
https://www.google.com/maps/@30.4161172,-88.8277286,3a,24.9y,173.78h,94.98t/data=!3m6!1e1!3m4!1sN1IQDLKTGHznubnJzg7iwA!2e0!7i16384!8i8192
Very nice! That's a great example of a positive-offset left turn for the opposing single lane left turn. This is preferred as it massively improves visibility for left turning traffic.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 27, 2022, 01:49:30 PM
Post by: jakeroot on March 27, 2022, 01:49:30 PM
The double left turn from MN-62 to southbound I-35E has a double left turn that operates permissively. MN has a ton of double permissive left turn "signal heads" but I don't believe many actually operate in permissive mode:
https://goo.gl/maps/qGwuB1yoWY5WZKnJ7
https://goo.gl/maps/qGwuB1yoWY5WZKnJ7
Title: Re: Double left turns with permissive phasing
Post by: Hobart on April 11, 2022, 10:54:33 AM
Post by: Hobart on April 11, 2022, 10:54:33 AM
I found another example in New Mexico.
https://www.google.com/maps/@35.1879789,-106.6140448,3a,62y,42.2h,87.09t/data=!3m6!1e1!3m4!1sZoh9IMh3tvRc28SaJ4smfA!2e0!7i16384!8i8192
You can't see the lanes clearly because there's other cars, but it's striped for two-lane left turns.
This is also very interesting because there's no obvious indication that the left turn is two lanes besides pavement markings. There's only one overhead signal, and no signage anywhere denoting lane usage.
https://www.google.com/maps/@35.1879789,-106.6140448,3a,62y,42.2h,87.09t/data=!3m6!1e1!3m4!1sZoh9IMh3tvRc28SaJ4smfA!2e0!7i16384!8i8192
You can't see the lanes clearly because there's other cars, but it's striped for two-lane left turns.
This is also very interesting because there's no obvious indication that the left turn is two lanes besides pavement markings. There's only one overhead signal, and no signage anywhere denoting lane usage.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 11, 2022, 05:29:05 PM
Post by: jakeroot on April 11, 2022, 05:29:05 PM
Quote from: Hobart on April 11, 2022, 10:54:33 AM
I found another example in New Mexico.
https://www.google.com/maps/@35.1879789,-106.6140448,3a,62y,42.2h,87.09t/data=!3m6!1e1!3m4!1sZoh9IMh3tvRc28SaJ4smfA!2e0!7i16384!8i8192
You can't see the lanes clearly because there's other cars, but it's striped for two-lane left turns.
This is also very interesting because there's no obvious indication that the left turn is two lanes besides pavement markings. There's only one overhead signal, and no signage anywhere denoting lane usage.
I don't know what New Mexico's rules are for double left turns, but it seems they have no rule specifically prohibiting permissive lefts with more than one lane.
Title: Re: Double left turns with permissive phasing
Post by: Hobart on April 12, 2022, 11:17:44 PM
Post by: Hobart on April 12, 2022, 11:17:44 PM
I should really do things during D&D besides look at Google Street View!
Found this example in Regina, Saskatchewan, not even using FYA's (because it's in Canada)!
https://www.google.com/maps/@50.4962855,-104.640998,3a,55.6y,356.64h,90.33t/data=!3m6!1e1!3m4!1sUZohFOprKKpvs9vNRPJjfg!2e0!7i16384!8i8192
Found this example in Regina, Saskatchewan, not even using FYA's (because it's in Canada)!
https://www.google.com/maps/@50.4962855,-104.640998,3a,55.6y,356.64h,90.33t/data=!3m6!1e1!3m4!1sUZohFOprKKpvs9vNRPJjfg!2e0!7i16384!8i8192
Title: Re: Double left turns with permissive phasing
Post by: JMAN_WiS&S on April 18, 2022, 10:22:45 PM
Post by: JMAN_WiS&S on April 18, 2022, 10:22:45 PM
Quote from: jakeroot on March 25, 2022, 02:06:07 PM
JMAN_WiS&S recently brought up Eau Claire, Wisconsin in another thread, and it reminded me to take a look around that place again.
I noticed that eastbound Clairemont to the northbound Hastings Way onramp has a double permissive left turn using flashing yellow arrows:
https://goo.gl/maps/n7DnBT2NXR9VsN1A9
In true Eau Claire fashion, there's plenty of signals! Unfortunately, I wasn't able to find any GSV of the left turn signals operating in permissive mode. If there are any locals that know of this intersections and could comment on how it operates, I'd love to know if it actually runs in permissive mode (perhaps at night).
I am said local! These dual FYAs along with the ones at Clairemont/Stein, begin their p/p phasing around 7:30-8pm during the weekday, and Clairemont/University around 7pm. On the weekend University is p/p 24hrs. The dual protected FYAs at Hastings & Brackett run recently switched to running protected only during the day, it switches to p/p around 7pm.
There are actually plans to swap the final WisDOT intersections that have 3 section LT heads in our area over to 4 section FYA heads in the next year or two, aside from the SPUI. STH 178/Seymour Cray Sr in Chippewa Falls now has a NB to WB dual left with p/p FYAs, running the same phasing as the clairemont ones do. River Prairie Dr & US53NB ramp in Altoona, STH 124 & CTH OO in Lake Hallie, and both of the STH 178 & STH 29 Ramp intersections in Chippewa Falls are set to be eventually converted to this head style. Not entirely sure if any of those will drop one of the left turn lanes to compensate. For a while Eau Claire had the highest concentration of protected only left turn signals in the entire state and now we have eliminated most of them 15 years later.
If you ever want to know more about anything Eau Claire feel free to shoot me a PM, I could go on for hours and hours, and can probably get you videos of just about anything too!
Title: Re: Double left turns with permissive phasing
Post by: Hobart on May 17, 2022, 05:36:12 PM
Post by: Hobart on May 17, 2022, 05:36:12 PM
It hasn't been a month yet since the last post, and I found another example in Salina, Kansas!
https://www.google.com/maps/@38.7980492,-97.6128301,3a,75y,43.84h,88.65t/data=!3m7!1e1!3m5!1spKlT61K6Vt9K3lOmsuW0fg!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DpKlT61K6Vt9K3lOmsuW0fg%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D14.805189%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192
https://www.google.com/maps/@38.7980492,-97.6128301,3a,75y,43.84h,88.65t/data=!3m7!1e1!3m5!1spKlT61K6Vt9K3lOmsuW0fg!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DpKlT61K6Vt9K3lOmsuW0fg%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D14.805189%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on May 17, 2022, 08:12:31 PM
Post by: jakeroot on May 17, 2022, 08:12:31 PM
Quote from: Hobart on May 17, 2022, 05:36:12 PM
It hasn't been a month yet since the last post, and I found another example in Salina, Kansas!
https://www.google.com/maps/@38.7980492,-97.6128301,3a,75y,43.84h,88.65t/data=!3m7!1e1!3m5!1spKlT61K6Vt9K3lOmsuW0fg!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DpKlT61K6Vt9K3lOmsuW0fg%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D14.805189%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192
Well found.
I wish they would have modified the oncoming left turn to positive-offset alignment (against oncoming traffic instead of against through traffic), as that would have improved visibility for left-turning traffic. But maybe it works okay. I know Tucson swears by some kind of clearance zone between the through lanes and the left turn lanes.
Title: Re: Double left turns with permissive phasing
Post by: Hobart on June 07, 2022, 09:44:04 PM
Post by: Hobart on June 07, 2022, 09:44:04 PM
Stolen from an intersection that's next to an intersection on the oversized reflector board thread.
https://www.google.com/maps/@33.2157385,-96.8608948,3a,15.4y,165.95h,90.59t/data=!3m6!1e1!3m4!1s8gjedreKTCdHjqQC9RvEkA!2e0!7i16384!8i8192
This freshly installed example in Frisco, Texas, has double FYA's, in Texas' double red arrow configuration. I imagine it's not going to be around for much longer as traffic demands increase.
EDIT: Shortly after I posted, I found that a few nearby intersections have examples as well!
https://www.google.com/maps/@33.2142146,-96.8454693,3a,75y,183.66h,109.27t/data=!3m6!1e1!3m4!1s6IGz1oACbVpwu8KEs4V1DA!2e0!7i16384!8i8192
https://www.google.com/maps/@33.209032,-96.8197297,3a,15y,271.47h,91.97t/data=!3m6!1e1!3m4!1sNC0Y4EGcP1PhBceuKjeypA!2e0!7i16384!8i8192
https://www.google.com/maps/@33.2040566,-96.8026837,3a,44.8y,262.88h,92.53t/data=!3m6!1e1!3m4!1s3Yfk8joPa93Cz3fsAe7Ifg!2e0!7i16384!8i8192
https://www.google.com/maps/@33.2339097,-96.8193084,3a,15y,269.45h,92.75t/data=!3m6!1e1!3m4!1sV2n9L0WfxAR2QidjeUYirg!2e0!7i16384!8i8192
https://www.google.com/maps/@33.2627725,-96.819274,3a,75y,293.54h,90.09t/data=!3m6!1e1!3m4!1sgAm1faxlCTbQspTx0eSdbg!2e0!7i16384!8i8192
I think all of these exist because construction of the roads in the area isn't complete yet; many of these intersections have additional empty space for lanes, or barricades indicating the road will be widened later. Dallas Parkway is also just feeder roads right now. It's interesting that the state would install protected-permissive signals on a temporary basis for this reason.
https://www.google.com/maps/@33.2157385,-96.8608948,3a,15.4y,165.95h,90.59t/data=!3m6!1e1!3m4!1s8gjedreKTCdHjqQC9RvEkA!2e0!7i16384!8i8192
This freshly installed example in Frisco, Texas, has double FYA's, in Texas' double red arrow configuration. I imagine it's not going to be around for much longer as traffic demands increase.
EDIT: Shortly after I posted, I found that a few nearby intersections have examples as well!
https://www.google.com/maps/@33.2142146,-96.8454693,3a,75y,183.66h,109.27t/data=!3m6!1e1!3m4!1s6IGz1oACbVpwu8KEs4V1DA!2e0!7i16384!8i8192
https://www.google.com/maps/@33.209032,-96.8197297,3a,15y,271.47h,91.97t/data=!3m6!1e1!3m4!1sNC0Y4EGcP1PhBceuKjeypA!2e0!7i16384!8i8192
https://www.google.com/maps/@33.2040566,-96.8026837,3a,44.8y,262.88h,92.53t/data=!3m6!1e1!3m4!1s3Yfk8joPa93Cz3fsAe7Ifg!2e0!7i16384!8i8192
https://www.google.com/maps/@33.2339097,-96.8193084,3a,15y,269.45h,92.75t/data=!3m6!1e1!3m4!1sV2n9L0WfxAR2QidjeUYirg!2e0!7i16384!8i8192
https://www.google.com/maps/@33.2627725,-96.819274,3a,75y,293.54h,90.09t/data=!3m6!1e1!3m4!1sgAm1faxlCTbQspTx0eSdbg!2e0!7i16384!8i8192
I think all of these exist because construction of the roads in the area isn't complete yet; many of these intersections have additional empty space for lanes, or barricades indicating the road will be widened later. Dallas Parkway is also just feeder roads right now. It's interesting that the state would install protected-permissive signals on a temporary basis for this reason.
Title: Re: Double left turns with permissive phasing
Post by: kphoger on June 08, 2022, 09:54:39 AM
Post by: kphoger on June 08, 2022, 09:54:39 AM
Quote from: Hobart on June 07, 2022, 09:44:04 PM
Stolen from an intersection that's next to an intersection on the oversized reflector board thread.
https://www.google.com/maps/@33.2157385,-96.8608948,3a,15.4y,165.95h,90.59t/data=!3m6!1e1!3m4!1s8gjedreKTCdHjqQC9RvEkA!2e0!7i16384!8i8192
This freshly installed example in Frisco, Texas, has double FYA's, in Texas' double red arrow configuration. I imagine it's not going to be around for much longer as traffic demands increase.
EDIT: Shortly after I posted, I found that a few nearby intersections have examples as well!
https://www.google.com/maps/@33.2142146,-96.8454693,3a,75y,183.66h,109.27t/data=!3m6!1e1!3m4!1s6IGz1oACbVpwu8KEs4V1DA!2e0!7i16384!8i8192
https://www.google.com/maps/@33.209032,-96.8197297,3a,15y,271.47h,91.97t/data=!3m6!1e1!3m4!1sNC0Y4EGcP1PhBceuKjeypA!2e0!7i16384!8i8192
https://www.google.com/maps/@33.2040566,-96.8026837,3a,44.8y,262.88h,92.53t/data=!3m6!1e1!3m4!1s3Yfk8joPa93Cz3fsAe7Ifg!2e0!7i16384!8i8192
https://www.google.com/maps/@33.2339097,-96.8193084,3a,15y,269.45h,92.75t/data=!3m6!1e1!3m4!1sV2n9L0WfxAR2QidjeUYirg!2e0!7i16384!8i8192
https://www.google.com/maps/@33.2627725,-96.819274,3a,75y,293.54h,90.09t/data=!3m6!1e1!3m4!1sgAm1faxlCTbQspTx0eSdbg!2e0!7i16384!8i8192
I think all of these exist because construction of the roads in the area isn't complete yet; many of these intersections have additional empty space for lanes, or barricades indicating the road will be widened later. Dallas Parkway is also just feeder roads right now. It's interesting that the state would install protected-permissive signals on a temporary basis for this reason.
Also interesting that they don't have white FYA signs next to the signal heads.
Title: Re: Double left turns with permissive phasing
Post by: roadfro on June 08, 2022, 11:35:14 AM
Post by: roadfro on June 08, 2022, 11:35:14 AM
Quote from: kphoger on June 08, 2022, 09:54:39 AM
Also interesting that they don't have white FYA signs next to the signal heads.
Technically, a sign is not required (despite so many jurisdictions using one). Since MUTCD didn't require or even recommend a sign, that probably explains why there's so many different FYA sign designs out there...
Title: Re: Double left turns with permissive phasing
Post by: kphoger on June 08, 2022, 12:03:53 PM
Post by: kphoger on June 08, 2022, 12:03:53 PM
Quote from: roadfro on June 08, 2022, 11:35:14 AMQuote from: kphoger on June 08, 2022, 09:54:39 AM
Also interesting that they don't have white FYA signs next to the signal heads.
Technically, a sign is not required (despite so many jurisdictions using one). Since MUTCD didn't require or even recommend a sign, that probably explains why there's so many different FYA sign designs out there...
It's just that it seems like I've always seen one in Texas wherever there's an FYA.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on June 12, 2022, 11:41:06 AM
Post by: fwydriver405 on June 12, 2022, 11:41:06 AM
Quote from: fwydriver405 on January 29, 2021, 09:09:07 PMQuote from: jakeroot on January 29, 2021, 02:19:18 PMQuote from: fwydriver405 on January 20, 2021, 07:29:08 PM
Saw two intersections with double permissive lefts on a recent trip to the University of Vermont for two games:
https://www.google.com/maps/@44.4744303,-73.1954092,3a,35.6y,54.89h,84.69t/data=!3m6!1e1!3m4!1sqU4mNlgDIpby3ZwN85XmVg!2e0!7i16384!8i8192 (this one is confirmed, as I saw the opposing direction also have a concurrent green as well.)
https://www.google.com/maps/@44.4758217,-73.1926487,3a,24.8y,186.4h,85.56t/data=!3m6!1e1!3m4!1sDMQ344T5QDAEkA_uedCzKQ!2e0!7i13312!8i6656
I continue to be surprised by how many exist in Vermont. Interesting that two would end up so close to each other.
Speaking of Vermont... I wonder if this double left in St Albans VT is still running permissive/protected at all since 2015, since the newer GSV's show this signal to run in protected only mode.
2015 GSV (permissve/protected) (https://www.google.com/maps/@44.8410292,-73.0837251,3a,28.9y,146.28h,87.99t/data=!3m7!1e1!3m5!1ss_p1yt6m1y8CWAY0RqqLgA!2e0!5s20151101T000000!7i13312!8i6656), Oct 2018 GSV (protected only?) (https://www.google.com/maps/@44.8408616,-73.0836262,3a,65.7y,143.64h,85.76t/data=!3m7!1e1!3m5!1sSLugCFgWB88T3YLoo3aNxg!2e0!5s20181001T000000!7i13312!8i6656)
Update on the Vermont double permissive lefts. Managed to visit all three locations on 11 June on a day trip to Burlington. Here is what I found:
US Route 2 at University Heights (https://www.google.com/maps/@44.4744303,-73.1954092,3a,35.6y,54.89h,84.69t/data=!3m6!1e1!3m4!1sqU4mNlgDIpby3ZwN85XmVg!2e0!7i16384!8i819) in Burlington in UVM is still running a double permissive left on the Univ. Heights approach. Seems to run a lagging left setup (yellow trap risk) since the first side street phases were green balls in both direction, but since side street volumes were low, the arrow never came on.
Beaumont Ave and Carrigan Drive (https://www.google.com/maps/@44.475821,-73.19265,3a,24.8y,186.4h,85.56t/data=!3m6!1e1!3m4!1sDMQ344T5QDAEkA_uedCzKQ!2e0!7i13312!8i6656), also in Burlington in UVM does NOT run a double permissive left setup, it ran split (with a green left arrow on one of the heads) when I drove thru there.
US Route 7 at Vermont Route 207 (https://www.google.com/maps/@44.8408532,-73.0836153,3a,29.3y,154.02h,87.84t/data=!3m6!1e1!3m4!1s7lcTy_AjEBNLYeDs24lLmg!2e0!7i13312!8i6656) in Saint Albans VT did NOT have the permissive phase active when I went there, even under what I assume was under free operations (although it seemed like it was running pretimed and not free... broken detector?)
Title: Re: Double left turns with permissive phasing
Post by: MASTERNC on June 20, 2022, 09:50:12 PM
Post by: MASTERNC on June 20, 2022, 09:50:12 PM
Saw a bunch of these in Minnesota (Maple Grove), though the FYA is sometimes inactive. What is also odd is there is only one left turn signal overhead (the second one is in the far left corner).
https://goo.gl/maps/oW78ms5eFzeo3CZF6
https://goo.gl/maps/LpKsdeZRKLJFLpV56
https://goo.gl/maps/oW78ms5eFzeo3CZF6
https://goo.gl/maps/LpKsdeZRKLJFLpV56
Title: Re: Double left turns with permissive phasing
Post by: Hobart on July 13, 2022, 08:42:27 PM
Post by: Hobart on July 13, 2022, 08:42:27 PM
In today's episode of "Hobart revives a dead thread by posting exactly once", I found an example in Sioux Falls!
https://www.google.com/maps/@43.5720182,-96.7726206,3a,54.5y,10.74h,96.51t/data=!3m7!1e1!3m5!1sZFfz1cHWzGpXwINEAdnyew!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DZFfz1cHWzGpXwINEAdnyew%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D123.33305%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192
At Maple and Russel streets, the off ramp from I-29 has a double permissive left turn that's phased with the opposing right turn. What makes this even more interesting is that the right turn is given a green arrow when the opposing left turn has a green ball.
https://www.google.com/maps/@43.57223,-96.7725141,3a,55.3y,205.38h,92.91t/data=!3m6!1e1!3m4!1sAiS_nhjU8gaN1md5mjV8sA!2e0!7i16384!8i8192
https://www.google.com/maps/@43.5720182,-96.7726206,3a,54.5y,10.74h,96.51t/data=!3m7!1e1!3m5!1sZFfz1cHWzGpXwINEAdnyew!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DZFfz1cHWzGpXwINEAdnyew%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D123.33305%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192
At Maple and Russel streets, the off ramp from I-29 has a double permissive left turn that's phased with the opposing right turn. What makes this even more interesting is that the right turn is given a green arrow when the opposing left turn has a green ball.
https://www.google.com/maps/@43.57223,-96.7725141,3a,55.3y,205.38h,92.91t/data=!3m6!1e1!3m4!1sAiS_nhjU8gaN1md5mjV8sA!2e0!7i16384!8i8192
Title: Re: Double left turns with permissive phasing
Post by: steviep24 on July 13, 2022, 09:12:06 PM
Post by: steviep24 on July 13, 2022, 09:12:06 PM
The intersection of NY 15 (Mt Hope Ave) and Westfall Rd/Westmoreland Rd. in Rochester, NY was recently rebuilt. Westfall Rd. now has double left turn lanes with protected/permissive phasing with FYA. This is the only such setup I know of in Rochester.
https://www.google.com/maps/@43.1144766,-77.6224815,3a,37.5y,283.2h,93.86t/data=!3m6!1e1!3m4!1sneeiWnOEs4cpSgjJvcZFHA!2e0!7i16384!8i8192?hl=en&authuser=0
https://www.google.com/maps/@43.1144766,-77.6224815,3a,37.5y,283.2h,93.86t/data=!3m6!1e1!3m4!1sneeiWnOEs4cpSgjJvcZFHA!2e0!7i16384!8i8192?hl=en&authuser=0
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 13, 2022, 09:27:32 PM
Post by: jakeroot on July 13, 2022, 09:27:32 PM
Quote from: Hobart on July 13, 2022, 08:42:27 PM
In today's episode of "Hobart revives a dead thread by posting exactly once", I found an example in Sioux Falls!
https://www.google.com/maps/@43.5720182,-96.7726206,3a,54.5y,10.74h,96.51t/data=!3m7!1e1!3m5!1sZFfz1cHWzGpXwINEAdnyew!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DZFfz1cHWzGpXwINEAdnyew%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D123.33305%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192
At Maple and Russel streets, the off ramp from I-29 has a double permissive left turn that's phased with the opposing right turn. What makes this even more interesting is that the right turn is given a green arrow when the opposing left turn has a green ball.
https://www.google.com/maps/@43.57223,-96.7725141,3a,55.3y,205.38h,92.91t/data=!3m6!1e1!3m4!1sAiS_nhjU8gaN1md5mjV8sA!2e0!7i16384!8i8192
Not to completely steal your thunder, but I did post this same intersection a couple years ago:
https://www.aaroads.com/forum/index.php?topic=17051.msg2496801#msg2496801
Quote from: steviep24 on July 13, 2022, 09:12:06 PM
The intersection of NY 15 (Mt Hope Ave) and Westfall Rd/Westmoreland Rd. in Rochester, NY was recently rebuilt. Westfall Rd. now has double left turn lanes with protected/permissive phasing with FYA. This is the only such setup I know of in Rochester.
https://www.google.com/maps/@43.1144766,-77.6224815,3a,37.5y,283.2h,93.86t/data=!3m6!1e1!3m4!1sneeiWnOEs4cpSgjJvcZFHA!2e0!7i16384!8i8192?hl=en&authuser=0
Very cool! Perhaps the only one upstate for that matter...there are a bunch in NYC-proper, but I'm not aware of others in the state.
Title: Re: Double left turns with permissive phasing
Post by: webny99 on July 13, 2022, 09:42:09 PM
Post by: webny99 on July 13, 2022, 09:42:09 PM
Quote from: jakeroot on July 13, 2022, 09:27:32 PMQuote from: steviep24 on July 13, 2022, 09:12:06 PM
The intersection of NY 15 (Mt Hope Ave) and Westfall Rd/Westmoreland Rd. in Rochester, NY was recently rebuilt. Westfall Rd. now has double left turn lanes with protected/permissive phasing with FYA. This is the only such setup I know of in Rochester.
https://www.google.com/maps/@43.1144766,-77.6224815,3a,37.5y,283.2h,93.86t/data=!3m6!1e1!3m4!1sneeiWnOEs4cpSgjJvcZFHA!2e0!7i16384!8i8192?hl=en&authuser=0
Very cool! Perhaps the only one upstate for that matter...there are a bunch in NYC-proper, but I'm not aware of others in the state.
Interesting. I'll have to check that out sometime. The new(-ish) installs on NY 15A at I-390 less than a mile away are protected-only. Wouldn't be surprised if it's because there's only a single oncoming lane.
This intersection also qualifies for my lanes that disappear mid-intersection (https://www.aaroads.com/forum/index.php?topic=30385.0) thread, so I'll post this there too. :)
Title: Re: Double left turns with permissive phasing
Post by: cl94 on July 13, 2022, 09:55:01 PM
Post by: cl94 on July 13, 2022, 09:55:01 PM
Quote from: jakeroot on July 13, 2022, 09:27:32 PMQuote from: Hobart on July 13, 2022, 08:42:27 PM
In today's episode of "Hobart revives a dead thread by posting exactly once", I found an example in Sioux Falls!
https://www.google.com/maps/@43.5720182,-96.7726206,3a,54.5y,10.74h,96.51t/data=!3m7!1e1!3m5!1sZFfz1cHWzGpXwINEAdnyew!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DZFfz1cHWzGpXwINEAdnyew%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D123.33305%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192
At Maple and Russel streets, the off ramp from I-29 has a double permissive left turn that's phased with the opposing right turn. What makes this even more interesting is that the right turn is given a green arrow when the opposing left turn has a green ball.
https://www.google.com/maps/@43.57223,-96.7725141,3a,55.3y,205.38h,92.91t/data=!3m6!1e1!3m4!1sAiS_nhjU8gaN1md5mjV8sA!2e0!7i16384!8i8192
Not to completely steal your thunder, but I did post this same intersection a couple years ago:
https://www.aaroads.com/forum/index.php?topic=17051.msg2496801#msg2496801Quote from: steviep24 on July 13, 2022, 09:12:06 PM
The intersection of NY 15 (Mt Hope Ave) and Westfall Rd/Westmoreland Rd. in Rochester, NY was recently rebuilt. Westfall Rd. now has double left turn lanes with protected/permissive phasing with FYA. This is the only such setup I know of in Rochester.
https://www.google.com/maps/@43.1144766,-77.6224815,3a,37.5y,283.2h,93.86t/data=!3m6!1e1!3m4!1sneeiWnOEs4cpSgjJvcZFHA!2e0!7i16384!8i8192?hl=en&authuser=0
Very cool! Perhaps the only one upstate for that matter...there are a bunch in NYC-proper, but I'm not aware of others in the state.
There are a few in NYC itself unless I'm missing a bunch. I think the one at Flatbush/Tillary may be gone now that the intersection was reconfigured to have a shared through/turn lane. Queens Boulevard is still there. The one in Rochester, yeah, that's the only one Upstate. I wonder if that operates as FYA 24/7 or only part-time.
Title: Re: Double left turns with permissive phasing
Post by: webny99 on July 13, 2022, 10:33:06 PM
Post by: webny99 on July 13, 2022, 10:33:06 PM
Given that Westmoreland Drive's AADT is only ~3500 vs. ~10,000 on Westfall, my guess is it's FYA 24/7. That's no more than a handful of eastbound cars per cycle except at peak times, so probably not busy enough to warrant a protected-only phase and a great trial location for a double-left FYA.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on July 14, 2022, 10:01:46 AM
Post by: mrsman on July 14, 2022, 10:01:46 AM
Quote from: webny99 on July 13, 2022, 10:33:06 PM
Given that Westmoreland Drive's AADT is only ~3500 vs. ~10,000 on Westfall, my guess is it's FYA 24/7. That's no more than a handful of eastbound cars per cycle except at peak times, so probably not busy enough to warrant a protected-only phase and a great trial location for a double-left FYA.
It's great that they are trying something new. The lack of permissive double lefts around NY (other than NYC) indicates that the DOTs are nervous about the concept, so to try out something that works well in other places and is legal and helpful to traffic is great. See if it works and then expand to other locations.
There are so many split-phased signals out there, because of a double left in one direction, that could probably be re-arranged to be permissive left given the realitiies of traffic flow. I know of several in my area that are similar to this, where oppsing traffic is very little so permissive lefts should be totally fine. But, alas, they are still stuck with the split-phase that delays the entire intersection.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 14, 2022, 10:49:55 AM
Post by: jakeroot on July 14, 2022, 10:49:55 AM
Quote from: cl94 on July 13, 2022, 09:55:01 PM
There are a few in NYC itself unless I'm missing a bunch. I think the one at Flatbush/Tillary may be gone now that the intersection was reconfigured to have a shared through/turn lane. Queens Boulevard is still there. The one in Rochester, yeah, that's the only one Upstate. I wonder if that operates as FYA 24/7 or only part-time.
Looks like Flatbush and Tillary is still permissive (https://goo.gl/maps/qhAr24U2Mtpnz1jq8). Based on the number of cars still in the intersection in my GSV link, hopefully there's a long all-red phase.
Edit: better link that actually shows what I was talking about.
Title: Re: Double left turns with permissive phasing
Post by: steviep24 on July 14, 2022, 05:06:20 PM
Post by: steviep24 on July 14, 2022, 05:06:20 PM
Quote from: jakeroot on July 14, 2022, 10:49:55 AMThe one at Ave U and Flatbush still appears to be a permissive double left (which was discussed in this thread ages ago.)Quote from: cl94 on July 13, 2022, 09:55:01 PM
There are a few in NYC itself unless I'm missing a bunch. I think the one at Flatbush/Tillary may be gone now that the intersection was reconfigured to have a shared through/turn lane. Queens Boulevard is still there. The one in Rochester, yeah, that's the only one Upstate. I wonder if that operates as FYA 24/7 or only part-time.
Looks like Flatbush and Tillary is still permissive (https://www.google.com/maps/place/Tillary+St,+Brooklyn,+NY+11201/@40.6958829,-73.9843571,3a,75y,344.1h,90t/data=!3m4!1e1!3m2!1siVB8XPBAw1nxZOXVqKPfew!2e0!4m2!3m1!1s0x89c25a35601a593f:0x5999666da9dadde). Based on the number of cars still in the intersection in my GSV link, hopefully there's a long all-red phase.
https://www.google.com/maps/@40.6102145,-73.9221447,3a,75y,179.81h,87.94t/data=!3m6!1e1!3m4!1svwNM06bFiNkVZZlenHfFJA!2e0!7i16384!8i8192
EDIT TO UPDATE: Just looked at the Google street view today. It's protected only now. Also, Ave U was renamed to Kings Plaza at least in that block.
Title: Re: Double left turns with permissive phasing
Post by: paulthemapguy on July 27, 2022, 12:55:16 PM
Post by: paulthemapguy on July 27, 2022, 12:55:16 PM
I found this dual-left turn lane with a flashing yellow arrow in Flagstaff, Arizona, for your consideration. It is the western end of the jog in a surface route following the old route of US89 (or Arizona 89A?).
https://goo.gl/maps/e2SzA1p8gkbzQFyR9
https://goo.gl/maps/e2SzA1p8gkbzQFyR9
Title: Re: Double left turns with permissive phasing
Post by: US 89 on July 27, 2022, 01:10:58 PM
Post by: US 89 on July 27, 2022, 01:10:58 PM
Quote from: paulthemapguy on July 27, 2022, 12:55:16 PM
I found this dual-left turn lane with a flashing yellow arrow in Flagstaff, Arizona, for your consideration. It is the western end of the jog in a surface route following the old route of US89 (or Arizona 89A?).
https://goo.gl/maps/e2SzA1p8gkbzQFyR9
That is the old route of SR 89A, which itself is the old route of US 89A. I don’t think it was ever US 89. SR 89A still exists but now hops on a concurrency with I-17 at exit 337.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on July 27, 2022, 02:04:25 PM
Post by: jakeroot on July 27, 2022, 02:04:25 PM
Quote from: paulthemapguy on July 27, 2022, 12:55:16 PM
I found this dual-left turn lane with a flashing yellow arrow in Flagstaff, Arizona, for your consideration. It is the western end of the jog in a surface route following the old route of US89 (or Arizona 89A?).
https://goo.gl/maps/e2SzA1p8gkbzQFyR9
It's not a flashing yellow arrow, from what I can tell. Red arrow > Yellow Arrow > Green Arrow > ??.
https://goo.gl/maps/4GALxs593eNpSPv8A
Looks like a yellow arrow on the bottom, but can't find any evidence of it being used. Maybe it flashes at night? Hmm.
Title: Re: Double left turns with permissive phasing
Post by: US 89 on August 13, 2022, 11:48:08 PM
Post by: US 89 on August 13, 2022, 11:48:08 PM
Drove through one last week in Montgomery AL, from Interstate Park Dr west onto Perry Hill Rd south:
https://goo.gl/maps/CNEFtaS85VYnZykJ9
https://goo.gl/maps/CNEFtaS85VYnZykJ9
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on August 14, 2022, 02:07:34 AM
Post by: jakeroot on August 14, 2022, 02:07:34 AM
Quote from: US 89 on August 13, 2022, 11:48:08 PM
Drove through one last week in Montgomery AL, from Interstate Park Dr west onto Perry Hill Rd south:
https://goo.gl/maps/CNEFtaS85VYnZykJ9
I think it might be split phased. Unless you saw for sure otherwise.
Title: Re: Double left turns with permissive phasing
Post by: US 89 on August 14, 2022, 09:12:54 AM
Post by: US 89 on August 14, 2022, 09:12:54 AM
Quote from: jakeroot on August 14, 2022, 02:07:34 AMQuote from: US 89 on August 13, 2022, 11:48:08 PM
Drove through one last week in Montgomery AL, from Interstate Park Dr west onto Perry Hill Rd south:
https://goo.gl/maps/CNEFtaS85VYnZykJ9
I think it might be split phased. Unless you saw for sure otherwise.
That would certainly make more sense, given that the other side only has one lane for all three movements. I don’t remember for sure - I was more focused on the tremendous thunderstorm that was coming through when I passed through here
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on November 07, 2022, 12:33:45 AM
Post by: jakeroot on November 07, 2022, 12:33:45 AM
I'm living in Japan now. Apart from a handful of intersections, at least here in Okinawa there are no protected right turns (Japan drives on the left, so right turns are across traffic). There are many right turns with two lanes as well, and these operate permissively just like the rest. I'm convinced there is at least one with three right turn lanes, but I haven't located one yet (I only know of one, in Tokyo). Here is an example near the Rycom Shopping Center (https://www.google.com/maps/@26.3164472,127.7936376,140m/data=!3m1!1e3), and one of the busiest intersections outside of Naha. It also has a westbound double left turn across the crosswalk; crossings in Japan are always concurrent with through traffic.
Most right turns have a dedicated box where traffic is designated to pull into while waiting to turn. If there is a gap, you are welcome to turn, although Japanese drivers are generally pretty conservative and don't shoot through tight gaps like back in the US. Especially because the protected phase is at the end, so there's not really a strict "need" to turn during the permissive phase. The waiting boxes are great because, effectively, half the turn is already complete when the green arrow comes on. You do have to be careful though, as the yellow lights are very short (maximum around 2 seconds, even at large intersections), so plenty of drivers are still coming at you when the green arrow comes on.
At some newer intersections, such as here in central Naha (https://goo.gl/maps/Jq66duV2tTtg8cQd8), the movement through the intersection is defined by dashed lines as well as colored pavement. In that example, the right turns following the blue pavement. This helps keep drivers in the lane as they turn, but seems much more effective than just using dashed lines when there is more than one turn lane. They are also used at single-lane turns when the turn is really long, such as here (https://goo.gl/maps/dxr3xWqG1uQMGhQ86).
Unrelated to double permissive turns, but just to give you some idea of how committed the Japanese are to permissive right turns: this three-level diamond has a single intersection beneath it that operates entirely permissive with a five-second all-red phase at the end (single turns only, though). You can have up to seven or eight cars in a single file line waiting to turn.
(https://live.staticflickr.com/65535/52483120019_349594f42d_o.jpg)
Okinawa Expy (E58) at Route 329 Bypass (https://flic.kr/p/2nXKH6D) by Jacob Root (https://www.flickr.com/photos/62537709@N03/), on Flickr
Most right turns have a dedicated box where traffic is designated to pull into while waiting to turn. If there is a gap, you are welcome to turn, although Japanese drivers are generally pretty conservative and don't shoot through tight gaps like back in the US. Especially because the protected phase is at the end, so there's not really a strict "need" to turn during the permissive phase. The waiting boxes are great because, effectively, half the turn is already complete when the green arrow comes on. You do have to be careful though, as the yellow lights are very short (maximum around 2 seconds, even at large intersections), so plenty of drivers are still coming at you when the green arrow comes on.
At some newer intersections, such as here in central Naha (https://goo.gl/maps/Jq66duV2tTtg8cQd8), the movement through the intersection is defined by dashed lines as well as colored pavement. In that example, the right turns following the blue pavement. This helps keep drivers in the lane as they turn, but seems much more effective than just using dashed lines when there is more than one turn lane. They are also used at single-lane turns when the turn is really long, such as here (https://goo.gl/maps/dxr3xWqG1uQMGhQ86).
Unrelated to double permissive turns, but just to give you some idea of how committed the Japanese are to permissive right turns: this three-level diamond has a single intersection beneath it that operates entirely permissive with a five-second all-red phase at the end (single turns only, though). You can have up to seven or eight cars in a single file line waiting to turn.
(https://live.staticflickr.com/65535/52483120019_349594f42d_o.jpg)
Okinawa Expy (E58) at Route 329 Bypass (https://flic.kr/p/2nXKH6D) by Jacob Root (https://www.flickr.com/photos/62537709@N03/), on Flickr
Title: Re: Double left turns with permissive phasing
Post by: Hobart on November 07, 2022, 04:15:44 PM
Post by: Hobart on November 07, 2022, 04:15:44 PM
Quote from: jakeroot on November 07, 2022, 12:33:45 AM
I'm living in Japan now. Apart from a handful of intersections, at least here in Okinawa there are no protected right turns (Japan drives on the left, so right turns are across traffic). There are many right turns with two lanes as well, and these operate permissively just like the rest. I'm convinced there is at least one with three right turn lanes, but I haven't located one yet (I only know of one, in Tokyo). Here is an example near the Rycom Shopping Center (https://www.google.com/maps/@26.3164472,127.7936376,140m/data=!3m1!1e3), and one of the busiest intersections outside of Naha. It also has a westbound double left turn across the crosswalk; crossings in Japan are always concurrent with through traffic.
Most right turns have a dedicated box where traffic is designated to pull into while waiting to turn. If there is a gap, you are welcome to turn, although Japanese drivers are generally pretty conservative and don't shoot through tight gaps like back in the US. Especially because the protected phase is at the end, so there's not really a strict "need" to turn during the permissive phase. The waiting boxes are great because, effectively, half the turn is already complete when the green arrow comes on. You do have to be careful though, as the yellow lights are very short (maximum around 2 seconds, even at large intersections), so plenty of drivers are still coming at you when the green arrow comes on.
At some newer intersections, such as here in central Naha (https://goo.gl/maps/Jq66duV2tTtg8cQd8), the movement through the intersection is defined by dashed lines as well as colored pavement. In that example, the right turns following the blue pavement. This helps keep drivers in the lane as they turn, but seems much more effective than just using dashed lines when there is more than one turn lane. They are also used at single-lane turns when the turn is really long, such as here (https://goo.gl/maps/dxr3xWqG1uQMGhQ86).
Unrelated to double permissive turns, but just to give you some idea of how committed the Japanese are to permissive right turns: this three-level diamond has a single intersection beneath it that operates entirely permissive with a five-second all-red phase at the end (single turns only, though). You can have up to seven or eight cars in a single file line waiting to turn.
(https://live.staticflickr.com/65535/52483120019_349594f42d_o.jpg)
Okinawa Expy (E58) at Route 329 Bypass (https://flic.kr/p/2nXKH6D) by Jacob Root (https://www.flickr.com/photos/62537709@N03/), on Flickr
I'd honestly be curious to see how well this works if they tried it in the states. Probably not well, but it would definitely be interesting. It seems to me like Japan actually sets up their intersections to have permissive turns with the dashed lines at intersections, rather than America where they just kind of half-ass them in last minute and rely on people's knowledge of the rules of the road to get them through.
What's also worth mentioning is that the waiting zones for some of those turns are curved. In the states, it's generally considered bad practice to keep your wheels turned to the left when making a permissive turn so you don't get forced into oncoming traffic if you're rear ended.
Also completely unrelated, but I like how Google is so detailed that it shows a horizontal traffic signal on Japanese Google Maps.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on November 08, 2022, 07:32:51 PM
Post by: jakeroot on November 08, 2022, 07:32:51 PM
Quote from: Hobart on November 07, 2022, 04:15:44 PM
I'd honestly be curious to see how well this works if they tried it in the states. Probably not well, but it would definitely be interesting. It seems to me like Japan actually sets up their intersections to have permissive turns with the dashed lines at intersections, rather than America where they just kind of half-ass them in last minute and rely on people's knowledge of the rules of the road to get them through.
What's also worth mentioning is that the waiting zones for some of those turns are curved. In the states, it's generally considered bad practice to keep your wheels turned to the left when making a permissive turn so you don't get forced into oncoming traffic if you're rear ended.
Also completely unrelated, but I like how Google is so detailed that it shows a horizontal traffic signal on Japanese Google Maps.
Japan 100% designs for permissive turns. The waiting boxes, the colored pavement, the green arrows at the end to catch anyone that doesn't make it...they've totally thought it through and, seeing it in person, I can confirm it's a great setup, even with two or more turn lanes.
The curved waiting zones make sense here as they don't generally design their turns with any positive offset (rare counter example here (https://goo.gl/maps/DwM7wR6sY72rL3ZV9)). Meaning, the medians are always to the right, no matter how wide. The curved waiting zones ensure that you pull out to an area where you can see traffic more easily. The double right turn boxes always have offset waiting lines too, so that one car doesn't block the view of another. It's all decently well designed. The whole issue with being rear-ended seems really odd to me. At least here, traffic that pulls into the right turn lanes is already slowing down, the chance of someone getting into the right turn lane and then ploughing full-speed into someone waiting seems really low. Especially at a speed high enough to cause traffic to go launching forward more than a meter at most.
Google Maps actually shows an incredible amount of detail in Japan. The horizontal traffic lights are great too, but they had all the extra detail (like exact roadway geometry) way before Google started launching that stuff in North America. It is really incredible, and one of the few reasons that I use Google Maps for navigation over here more than Waze...not just because it has more info, like street names, but it just shows more detail.
Title: Re: Double left turns with permissive phasing
Post by: sprjus4 on January 17, 2023, 12:09:42 AM
Post by: sprjus4 on January 17, 2023, 12:09:42 AM
Apologies if this was mentioned previously (I didn't read through all pages), but I found one today in Virginia (I didn't realize they existed in this state at all). The double left turn onto the I-64 west ramp at Exit 91 VA-285 is flashing yellow.
https://maps.app.goo.gl/nNvRx31ETYBy4R8XA?g_st=ic
https://maps.app.goo.gl/nNvRx31ETYBy4R8XA?g_st=ic
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on January 17, 2023, 08:33:03 AM
Post by: jakeroot on January 17, 2023, 08:33:03 AM
Quote from: sprjus4 on January 17, 2023, 12:09:42 AM
Apologies if this was mentioned previously (I didn't read through all pages), but I found one today in Virginia (I didn't realize they existed in this state at all). The double left turn onto the I-64 west ramp at Exit 91 VA-285 is flashing yellow.
https://maps.app.goo.gl/nNvRx31ETYBy4R8XA?g_st=ic
I think this was shared before, but not in this thread. I had been looking for this location, as someone had shared it a while back. But I hadn't been able to figure out where it was. Thank you for posting it.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 09, 2023, 02:02:07 AM
Post by: jakeroot on February 09, 2023, 02:02:07 AM
Here is the triple right turn with permissive phasing in Japan I have referred to before (either here or elsewhere).
I seem to remember it being in Tokyo, but it's actually in Osaka. It was changed from a double permissive turn to triple permissive turn in 2014.
https://goo.gl/maps/1DLwzpMDsrs4mLdF7
edit: for anyone wanting to see more pictures of it, search "天王寺駅ジャンクション" on Google. There is a major metro station beneath.
(https://www.photolibrary.jp/mhd6/img358/450-20140901103749111118.jpg)
I seem to remember it being in Tokyo, but it's actually in Osaka. It was changed from a double permissive turn to triple permissive turn in 2014.
https://goo.gl/maps/1DLwzpMDsrs4mLdF7
edit: for anyone wanting to see more pictures of it, search "天王寺駅ジャンクション" on Google. There is a major metro station beneath.
(https://www.photolibrary.jp/mhd6/img358/450-20140901103749111118.jpg)
Title: Re: Double left turns with permissive phasing
Post by: ran4sh on February 09, 2023, 11:00:40 AM
Post by: ran4sh on February 09, 2023, 11:00:40 AM
That would never work with American drivers
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 09, 2023, 05:49:04 PM
Post by: jakeroot on February 09, 2023, 05:49:04 PM
Quote from: ran4sh on February 09, 2023, 11:00:40 AM
That would never work with American drivers
I'd love to see it tried somewhere, but doubt any engineer has the courage to give it a shot.
The issue in Japan with turning traffic doesn't have anything to do with how many lanes there are, but actually oncoming traffic not stopping even after their light is red. Drivers here really push yellow lights, with many entering on red, even two or three seconds after it has come up. This isn't too big of a deal, as the green arrow comes on at the end, giving you plenty of time to wait a moment before finishing your turn. Still, some drivers really push the lights here far worse than anything I've seen anywhere in the US.
edit: fixed sentence missing words.
Title: Re: Double left turns with permissive phasing
Post by: Hobart on February 12, 2023, 10:20:35 PM
Post by: Hobart on February 12, 2023, 10:20:35 PM
Found another example at Front Street and Chouteau Trafficway in Kansas City, Missouri!
This one's especially interesting... not only does it have double towers of 5, it has double towers of 5 for the far-side supplemental left turn signal (which no other approach has), a doghouse on one leg, and a four-section in permissive operation in another... just weird all around.
https://www.google.com/maps/@39.1307471,-94.5232406,3a,75y,72.83h,97.52t/data=!3m6!1e1!3m4!1sRfQQWgtWVNxpiidgS_D4ZA!2e0!7i16384!8i8192
This one's especially interesting... not only does it have double towers of 5, it has double towers of 5 for the far-side supplemental left turn signal (which no other approach has), a doghouse on one leg, and a four-section in permissive operation in another... just weird all around.
https://www.google.com/maps/@39.1307471,-94.5232406,3a,75y,72.83h,97.52t/data=!3m6!1e1!3m4!1sRfQQWgtWVNxpiidgS_D4ZA!2e0!7i16384!8i8192
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 12, 2023, 10:26:40 PM
Post by: jakeroot on February 12, 2023, 10:26:40 PM
Quote from: Hobart on February 12, 2023, 10:20:35 PM
Found another example at Front Street and Chouteau Trafficway in Kansas City, Missouri!
This one's especially interesting... not only does it have double towers of 5, it has double towers of 5 for the far-side supplemental left turn signal (which no other approach has), a doghouse on one leg, and a four-section in permissive operation in another... just weird all around.
https://www.google.com/maps/@39.1307471,-94.5232406,3a,75y,72.83h,97.52t/data=!3m6!1e1!3m4!1sRfQQWgtWVNxpiidgS_D4ZA!2e0!7i16384!8i8192
Great find. That is indeed a very unique setup, with the double supplemental left turn 5-section towers. I think I've seen that once or twice, but that's considering the entirety of the US. Particularly unusual for Missouri and Kansas where left-side supplemental signals aren't particularly common anyways. And the mix of signal displays is very odd! I can only think of one intersection with a mix like that, here in Des Moines, WA (https://goo.gl/maps/iEMkix313d1ZtKgr5).
Title: Re: Double left turns with permissive phasing
Post by: Hobart on February 23, 2023, 09:09:17 PM
Post by: Hobart on February 23, 2023, 09:09:17 PM
I found probably the most scuffed example so far.
https://www.google.com/maps/@29.5575179,-98.5350833,3a,41.3y,157.23h,90.45t/data=!3m7!1e1!3m5!1sgQYsQZIYCibuNSbh6kW8lA!2e0!5s20190701T000000!7i16384!8i8192
This is in San Antonio. They have a doghouse and an FYA right next to each other... with both information placards! How the hell is this supposed to work?
https://www.google.com/maps/@29.5575179,-98.5350833,3a,41.3y,157.23h,90.45t/data=!3m7!1e1!3m5!1sgQYsQZIYCibuNSbh6kW8lA!2e0!5s20190701T000000!7i16384!8i8192
This is in San Antonio. They have a doghouse and an FYA right next to each other... with both information placards! How the hell is this supposed to work?
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 24, 2023, 07:37:32 PM
Post by: jakeroot on February 24, 2023, 07:37:32 PM
Quote from: Hobart on February 23, 2023, 09:09:17 PM
I found probably the most scuffed example so far.
https://www.google.com/maps/@29.5575179,-98.5350833,3a,41.3y,157.23h,90.45t/data=!3m7!1e1!3m5!1sgQYsQZIYCibuNSbh6kW8lA!2e0!5s20190701T000000!7i16384!8i8192
This is in San Antonio. They have a doghouse and an FYA right next to each other... with both information placards! How the hell is this supposed to work?
Lost of potential, though! They could have added a flashing yellow arrow to the doghouse, and it could have ended up like this FYA/doghouse combo in MN:
https://goo.gl/maps/y1EVTe4XtsRTUmsX9
https://youtu.be/onyZQcgkMOw
Title: Re: Double left turns with permissive phasing
Post by: roadfro on February 25, 2023, 03:31:05 PM
Post by: roadfro on February 25, 2023, 03:31:05 PM
Quote from: jakeroot on February 24, 2023, 07:37:32 PMQuote from: Hobart on February 23, 2023, 09:09:17 PM
I found probably the most scuffed example so far.
https://www.google.com/maps/@29.5575179,-98.5350833,3a,41.3y,157.23h,90.45t/data=!3m7!1e1!3m5!1sgQYsQZIYCibuNSbh6kW8lA!2e0!5s20190701T000000!7i16384!8i8192
This is in San Antonio. They have a doghouse and an FYA right next to each other... with both information placards! How the hell is this supposed to work?
Lost of potential, though! They could have added a flashing yellow arrow to the doghouse, and it could have ended up like this FYA/doghouse combo in MN:
https://goo.gl/maps/y1EVTe4XtsRTUmsX9
Jake's example for the combo FYA & 5-section makes sense, given the characteristics of the depicted approach and the opposing approach being relatively minor (commercial center parking access) with likely modest volumes.
I am somewhat intrigued by the situation Hobart posted though. The depicted approach is left-shared left/thru-thru-thru, so that 5-section display over the shared lane is non-compliant. But it looks like the cross street has a wide median–the overall operation along FM 1535 appears to be split phased, and this particular signal appears to be running an overlap, so that gives it a little more leeway. It looks like this situation will disappear soon though, as the most recent Street View appears to be converting this overall intersection into something a bit more akin to a SPUI.
Title: Re: Double left turns with permissive phasing
Post by: CovalenceSTU on February 26, 2023, 12:38:01 AM
Post by: CovalenceSTU on February 26, 2023, 12:38:01 AM
Just discovered that Lafayette, LA is filled with permissive double lefts, here's one that uses R/YA/(FYA/GA) signals:
(https://i.imgur.com/841N4fT.png)(https://i.imgur.com/iWJQWqA.png)
(https://i.imgur.com/Fr9Ji83.png)
https://goo.gl/maps/VXRyWvzXxmcyig2FA
And another one that uses double doghouses and a 5-section signal on the left:
(https://i.imgur.com/tYVd6tG.png)
https://goo.gl/maps/FpAUvRPh6qYyVRGS8
(https://i.imgur.com/841N4fT.png)(https://i.imgur.com/iWJQWqA.png)
(https://i.imgur.com/Fr9Ji83.png)
https://goo.gl/maps/VXRyWvzXxmcyig2FA
And another one that uses double doghouses and a 5-section signal on the left:
(https://i.imgur.com/tYVd6tG.png)
https://goo.gl/maps/FpAUvRPh6qYyVRGS8
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 26, 2023, 02:45:41 AM
Post by: jakeroot on February 26, 2023, 02:45:41 AM
Quote from: CovalenceSTU on February 26, 2023, 12:38:01 AM
Just discovered that Lafayette, LA is filled with permissive double lefts, here's one that uses R/YA/(FYA/GA) signals:
....
Really cool find. I actually had a pin saved on my Google Maps of one of the other double-left FYA signals in Lafayette. They definitely aren't afraid of dual permissive turns.
Couple other oddities in Lafayette: (1) they also are keen on double right turns with yield signs (here (https://goo.gl/maps/U4XqFVFJ9jNQ6G1w5) and here (https://goo.gl/maps/xREAdecUYQ6h94pA7) being examples), and (2) this double left turn (https://goo.gl/maps/Vqxk2nAe9xG5aQcq9) has an almost absurd amount of offset, even I'm not sure I would have used a yield there, visibility must be awful for the left-left turn lane.
Edit: forgot to mention, but I really like the supplemental signage used in Lafayette. Really helpful and to-the-point.
Title: Re: Double left turns with permissive phasing
Post by: CovalenceSTU on February 26, 2023, 10:24:34 PM
Post by: CovalenceSTU on February 26, 2023, 10:24:34 PM
I looked at a few more intersections there and I have to agree - they get plenty of things right regarding traffic control, but there's no shortage of oddities. They also use double white lines through intersections to mandate turning into the closest lane, presumably to allow left and right turns onto the same road at the same time (also featuring the best sign-related Google Maps stitching error I've seen):
(https://i.imgur.com/BTymbWl.png)
They're also very committed to using circular red for left turn signals, even when it's on a separate phase (which cannot possibly be MUTCD compliant):
(https://i.imgur.com/5b1dSNL.png)
(https://i.imgur.com/BTymbWl.png)
They're also very committed to using circular red for left turn signals, even when it's on a separate phase (which cannot possibly be MUTCD compliant):
(https://i.imgur.com/5b1dSNL.png)
Title: Re: Double left turns with permissive phasing
Post by: Hobart on February 26, 2023, 10:59:26 PM
Post by: Hobart on February 26, 2023, 10:59:26 PM
I can't decide what I'm more fascinated by... the supplemental signage, a willingness to use double left turns in the first place, using FYAs with red balls well after red balls for left turn signals fell out of favor, or the fact they even include far side supplemental left turns! I'm excited by that last bit, especially for a southern state!
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on February 27, 2023, 06:00:49 PM
Post by: jakeroot on February 27, 2023, 06:00:49 PM
Quote from: CovalenceSTU on February 26, 2023, 10:24:34 PM
They're also very committed to using circular red for left turn signals, even when it's on a separate phase (which cannot possibly be MUTCD compliant):
https://i.imgur.com/5b1dSNL.png
I noticed that too, even their very new left turn signals continue to use red orbs. It's definitely not MUTCD-compliant (unless there is split-phasing), and hasn't been since the 2009 MUTCD was released (plus a couple years for LADOT adoption, Lafayette adoption, and eventual incorporation into projects, all of which should have happened 10+ years ago).
Quote from: Hobart on February 26, 2023, 10:59:26 PM
I can't decide what I'm more fascinated by... the supplemental signage, a willingness to use double left turns in the first place, using FYAs with red balls well after red balls for left turn signals fell out of favor, or the fact they even include far side supplemental left turns! I'm excited by that last bit, especially for a southern state!
I'm with you there, it is a very interesting combination of things. All except for the red-orb left turn signals I am a fan of, for sure. Why they've kept using those, I do not understand at all, especially with how long they've been non-compliant.
I also really like their road markings. These days it seems like some places are very inconsistent, like the road markings aren't done with much care or consistency. Lafayette seems to be very consistent in their design, everything seems to be kept up in good shape, they always paint the left turn lane with some offset to improve visibility and create a very nice island between the through and left turn lanes (example here (https://goo.gl/maps/Fw3SrC3uWx3PB3Mj8))....it's just all really well done.
Title: Re: Double left turns with permissive phasing
Post by: Hobart on April 14, 2023, 01:25:48 AM
Post by: Hobart on April 14, 2023, 01:25:48 AM
After about a month and a half, I stumbled across another example in Elgin, Illinois!
https://www.google.com/maps/@42.036633,-88.2874339,3a,75.5y,155.63h,92.85t/data=!3m6!1e1!3m4!1sFqWAMCMmaGzTCQpTP-bT9A!2e0!7i16384!8i8192
Also of note is the large Texas U-Turn style frontage road on the left side of the street.
https://www.google.com/maps/@42.036633,-88.2874339,3a,75.5y,155.63h,92.85t/data=!3m6!1e1!3m4!1sFqWAMCMmaGzTCQpTP-bT9A!2e0!7i16384!8i8192
Also of note is the large Texas U-Turn style frontage road on the left side of the street.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on April 16, 2023, 06:30:43 AM
Post by: jakeroot on April 16, 2023, 06:30:43 AM
Quote from: Hobart on April 14, 2023, 01:25:48 AM
After about a month and a half, I stumbled across another example in Elgin, Illinois!
https://www.google.com/maps/@42.036633,-88.2874339,3a,75.5y,155.63h,92.85t/data=!3m6!1e1!3m4!1sFqWAMCMmaGzTCQpTP-bT9A!2e0!7i16384!8i8192
Also of note is the large Texas U-Turn style frontage road on the left side of the street.
I think this is how option lanes should be designed if possible. Split-phasing where there is no oncoming left seems kind of odd to me, even though it's the only option when most DOT's ban permissive turns with more than one lane.
Ironically given the Texas-style U-turn, this style of phasing with option lanes is probably most common in Texas.
Title: Re: Double left turns with permissive phasing
Post by: roadman65 on May 01, 2023, 04:11:57 PM
Post by: roadman65 on May 01, 2023, 04:11:57 PM
https://goo.gl/maps/7vj3WM2jMBgQamSC6
Here is one with no permissive or protected phasing. However, this is a split phase set up where both sides of the road have separate greens, so in reality it's a protected left. Just that being NJ doesn't use arrows in some places for these split phases, it's not the normal practice for split phases we know of and is not the separate left turn signal phase you normally see.
Here is one with no permissive or protected phasing. However, this is a split phase set up where both sides of the road have separate greens, so in reality it's a protected left. Just that being NJ doesn't use arrows in some places for these split phases, it's not the normal practice for split phases we know of and is not the separate left turn signal phase you normally see.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on May 01, 2023, 06:45:42 PM
Post by: jakeroot on May 01, 2023, 06:45:42 PM
Quote from: roadman65 on May 01, 2023, 04:11:57 PM
https://goo.gl/maps/7vj3WM2jMBgQamSC6
Here is one with no permissive or protected phasing. However, this is a split phase set up where both sides of the road have separate greens, so in reality it's a protected left. Just that being NJ doesn't use arrows in some places for these split phases, it's not the normal practice for split phases we know of and is not the separate left turn signal phase you normally see.
The extremely rare examples of split-phasing here in Japan are like this, with no green arrows whatsoever. Obviously drivers are going to figure out what is going on within a few seconds, and drivers who regularly use the intersection already know the operations, but it seems like it might invite undue hesitation from drivers unfamiliar with the operation.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on May 01, 2023, 07:01:35 PM
Post by: fwydriver405 on May 01, 2023, 07:01:35 PM
Found an Ontario example of such double PPLT phasing in Cornwell, Ontario (https://www.google.com/maps/@45.0123869,-74.739132,3a,26.1y,168.23h,93.42t/data=!3m6!1e1!3m4!1sGBEG89JSOgylv9k4E6FJ9A!2e0!7i16384!8i8192) near the USA/Canada border while looking up routes to Toronto from NH/Vermont.
How common are double permissive lefts in Canada, especially in Ontario and Québec?
How common are double permissive lefts in Canada, especially in Ontario and Québec?
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on May 01, 2023, 07:25:19 PM
Post by: jakeroot on May 01, 2023, 07:25:19 PM
Quote from: fwydriver405 on May 01, 2023, 07:01:35 PM
Found an Ontario example of such double PPLT phasing in Cornwell, Ontario (https://www.google.com/maps/@45.0123869,-74.739132,3a,26.1y,168.23h,93.42t/data=!3m6!1e1!3m4!1sGBEG89JSOgylv9k4E6FJ9A!2e0!7i16384!8i8192) near the USA/Canada border while looking up routes to Toronto from NH/Vermont.
Great find! Clean and very new example. Very unusual for Ontario to install this, though I'm pretty sure at least one other exists somewhere else.
This is exactly the kind of scenario where I think double permissive turns should be acceptable: no oncoming left (excellent visibility), and relatively quiet approach.
Quote from: fwydriver405 on May 01, 2023, 07:01:35 PM
How common are double permissive lefts in Canada, especially in Ontario and Québec?
I've been led to believe they are incredibly rare in Ontario and Quebec. However, out west, they are much more common. British Columbia has a half dozen examples I can think of. Alberta has a ton though almost all are in Edmonton (though they've fallen out of favor; it was the norm just ten years ago). Though sparsely populated, I believe Saskatchewan and Manitoba have quite a few examples too.
Title: Re: Double left turns with permissive phasing
Post by: RestrictOnTheHanger on May 11, 2023, 09:53:09 PM
Post by: RestrictOnTheHanger on May 11, 2023, 09:53:09 PM
Another NYC example, this intersection was recently changed to a lagging PPLT with FYAs replacing NYC style 5 section left turn signals. Not sure if it counts though since this leg can only turn left.
https://maps.app.goo.gl/FGaTNbAMYDS42LDE7
https://maps.app.goo.gl/FGaTNbAMYDS42LDE7
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on May 12, 2023, 12:31:47 AM
Post by: jakeroot on May 12, 2023, 12:31:47 AM
Quote from: RestrictOnTheHanger on May 11, 2023, 09:53:09 PM
Another NYC example, this intersection was recently changed to a lagging PPLT with FYAs replacing NYC style 5 section left turn signals. Not sure if it counts though since this leg can only turn left.
https://maps.app.goo.gl/FGaTNbAMYDS42LDE7
Works for me! Still yielding to pedestrians and vehicles.
Odd the "wait for green" sign was left up. Kind of sends the wrong message with a flashing yellow arrow.
Title: Re: Double left turns with permissive phasing
Post by: RestrictOnTheHanger on May 12, 2023, 12:11:53 PM
Post by: RestrictOnTheHanger on May 12, 2023, 12:11:53 PM
Quote from: jakeroot on May 12, 2023, 12:31:47 AMQuote from: RestrictOnTheHanger on May 11, 2023, 09:53:09 PM
Another NYC example, this intersection was recently changed to a lagging PPLT with FYAs replacing NYC style 5 section left turn signals. Not sure if it counts though since this leg can only turn left.
https://maps.app.goo.gl/FGaTNbAMYDS42LDE7
Works for me! Still yielding to pedestrians and vehicles.
Odd the "wait for green" sign was left up. Kind of sends the wrong message with a flashing yellow arrow.
Agreed, but I think it was there because the cross street had one side turn red before the other, so drivers saw most traffic stop and tried to jump their own red light.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on May 25, 2023, 01:08:20 AM
Post by: fwydriver405 on May 25, 2023, 01:08:20 AM
Quote from: jakeroot on May 01, 2023, 07:25:19 PM
I've been led to believe they are incredibly rare in Ontario and Quebec.
Poking around GSV, this left turn in Montréal (https://www.google.com/maps/@45.5084184,-73.5618962,3a,41.7y,31.65h,83.66t/data=!3m7!1e1!3m5!1s7p0OHo37tF8q2OzNelX_IQ!2e0!5s20140401T000000!7i13312!8i6656?hl=en) used to be double permissive (L-LT) up till around the summer of 2014. It is now protected only with only 1 turning lane since then and when I was there on a Friday and Saturday, there were long queues and some split failures at this left turn.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on May 26, 2023, 09:21:44 PM
Post by: jakeroot on May 26, 2023, 09:21:44 PM
Quote from: fwydriver405 on May 25, 2023, 01:08:20 AMQuote from: jakeroot on May 01, 2023, 07:25:19 PM
I've been led to believe they are incredibly rare in Ontario and Quebec.
Poking around GSV, this left turn in Montréal (https://www.google.com/maps/@45.5084184,-73.5618962,3a,41.7y,31.65h,83.66t/data=!3m7!1e1!3m5!1s7p0OHo37tF8q2OzNelX_IQ!2e0!5s20140401T000000!7i13312!8i6656?hl=en) used to be double permissive (L-LT) up till around the summer of 2014. It is now protected only with only 1 turning lane since then and when I was there on a Friday and Saturday, there were long queues and some split failures at this left turn.
Nice find! Never seen one in Quebec before, to be honest. I was assuming they were rare as none have been brought up here before.
I find it odd they'd remove the outside turn lane (except for buses) and change it to protected-only. Seems like it could still operate permissively as it stands.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on May 31, 2023, 07:41:51 AM
Post by: jakeroot on May 31, 2023, 07:41:51 AM
Found an example in Flagstaff, AZ. Uses flashing yellow arrows. It was installed sometime around late 2015 or early 2016.
Southbound Beulah Blvd towards eastbound Lake Mary Road (https://goo.gl/maps/wspDqSQq4qfVHeUn8)
It seems to operate with some kind of time-of-day phasing, as there are quite a few GSV images where it shows red arrows, like here (https://goo.gl/maps/DjvQFhocZ8jewbww8).
Speaking generally, Arizona has a lot of double permissive left turns, although they are mostly found in the same couple of cities (Tucson, Chandler, maybe one other). I've not known Flagstaff to use this phasing on a regular basis.
EDIT: At least one more example. This one uses four-section bi-modal "yield on green" signals, and was installed in late 2007/early 2008:
Westbound Marketplace Dr onto southbound US-89 (https://goo.gl/maps/itdWUuYTVtuVmUf47) (alt view looking other way (https://goo.gl/maps/R32h8it6J4ojXqAs6))
EDIT 2: Another one up the street. This one is fully permissive; opposing road is a KOA facility, so likely not much traffic:
Westbound Smokerise Dr onto southbound US-89 (https://goo.gl/maps/fHqTmtsZu8bs34Jm7) (spin camera around to see opposing green signal).
Southbound Beulah Blvd towards eastbound Lake Mary Road (https://goo.gl/maps/wspDqSQq4qfVHeUn8)
It seems to operate with some kind of time-of-day phasing, as there are quite a few GSV images where it shows red arrows, like here (https://goo.gl/maps/DjvQFhocZ8jewbww8).
Speaking generally, Arizona has a lot of double permissive left turns, although they are mostly found in the same couple of cities (Tucson, Chandler, maybe one other). I've not known Flagstaff to use this phasing on a regular basis.
EDIT: At least one more example. This one uses four-section bi-modal "yield on green" signals, and was installed in late 2007/early 2008:
Westbound Marketplace Dr onto southbound US-89 (https://goo.gl/maps/itdWUuYTVtuVmUf47) (alt view looking other way (https://goo.gl/maps/R32h8it6J4ojXqAs6))
EDIT 2: Another one up the street. This one is fully permissive; opposing road is a KOA facility, so likely not much traffic:
Westbound Smokerise Dr onto southbound US-89 (https://goo.gl/maps/fHqTmtsZu8bs34Jm7) (spin camera around to see opposing green signal).
Title: Re: Double left turns with permissive phasing
Post by: andrepoiy on June 04, 2023, 10:44:14 AM
Post by: andrepoiy on June 04, 2023, 10:44:14 AM
Thanks to Reddit, now I know of a permissive double-left in Canada.
There was this video where left-turning vehicles on a permissive left did not yield to oncoming traffic:
https://www.reddit.com/r/IdiotsInCars/comments/13zul1x/what_was_the_best_move_in_this_situation/
I have investigated and have found that this is a left-turn and left/straight lane, with the signals indicating a permissive/protected left.
(https://i.imgur.com/K4b5775.png)
Link: https://goo.gl/maps/bLfCyfCD5iGQszzG8
There was this video where left-turning vehicles on a permissive left did not yield to oncoming traffic:
https://www.reddit.com/r/IdiotsInCars/comments/13zul1x/what_was_the_best_move_in_this_situation/
I have investigated and have found that this is a left-turn and left/straight lane, with the signals indicating a permissive/protected left.
(https://i.imgur.com/K4b5775.png)
Link: https://goo.gl/maps/bLfCyfCD5iGQszzG8
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on June 04, 2023, 08:23:32 PM
Post by: jakeroot on June 04, 2023, 08:23:32 PM
Quote from: andrepoiy on June 04, 2023, 10:44:14 AM
Thanks to Reddit, now I know of a permissive double-left in Canada.
There was this video where left-turning vehicles on a permissive left did not yield to oncoming traffic:
https://www.reddit.com/r/IdiotsInCars/comments/13zul1x/what_was_the_best_move_in_this_situation/
I have investigated and have found that this is a left-turn and left/straight lane, with the signals indicating a permissive/protected left.
(https://i.imgur.com/K4b5775.png)
Link: https://goo.gl/maps/bLfCyfCD5iGQszzG8
Great find! Too bad it wasn't on better terms :-D. Though perhaps the driver going straight needs to use more caution. One driver screwing up can be offset by someone driving more defensively.
The setup is actually identical to the very first double permissive left that I ever encountered in Canada, turning left from Main St onto the Dunsmuir Viaduct in Vancouver (https://goo.gl/maps/AmirnCfvQrguUckx9).
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on June 07, 2023, 04:43:04 AM
Post by: jakeroot on June 07, 2023, 04:43:04 AM
I did some research on Japan's "largest intersections", and it turns out the one most commonly cited is on National Route 4 (Sendai Bypass) at Miyagi Prefectural Route 137:
https://goo.gl/maps/5rq78gKtHQKhV4b19
Of note, the triple right turn lanes, until very recently, operated with permissive phasing (https://goo.gl/maps/2RvdebxVjVictdvc9). This intersection (as well as one to the north) are the only intersections anywhere in the world (that I've located so far) with directly-opposing triple turns that operated permissively.
The two intersections. This is the one mentioned in the tweet above:
(https://fanblogs.jp/oortcloud/file/undefined/E585ADE4B881E381AEE79BAEE4BAA4E5B7AEE782B9.jpg)
And this is the other one to the north, which also operated permissively (https://goo.gl/maps/euQgF4NXKPVkPNmL8) (though with time-of-day phasing implemented in 2013), which has since been modified with an overpass:
(https://fanblogs.jp/oortcloud/file/undefined/E7AEB1E5A0A4E4BAA4E5B7AEE782B9.jpg)
In this tweet, the person actually states that they are afraid when turning right. However, I think the concern is more with the triple right turns, not that they were "free" right turns....
https://twitter.com/yujin0131rs/status/1324330141196021760
Lastly, someone made a YouTube video about it too. You can see it in permissive mode around 4:50 onwards, and then a timelapse at 8:00 (immediately preceded by a woman complaining about the length of the crossing)...
https://youtu.be/q9IvniFzRZU
https://goo.gl/maps/5rq78gKtHQKhV4b19
Of note, the triple right turn lanes, until very recently, operated with permissive phasing (https://goo.gl/maps/2RvdebxVjVictdvc9). This intersection (as well as one to the north) are the only intersections anywhere in the world (that I've located so far) with directly-opposing triple turns that operated permissively.
The two intersections. This is the one mentioned in the tweet above:
(https://fanblogs.jp/oortcloud/file/undefined/E585ADE4B881E381AEE79BAEE4BAA4E5B7AEE782B9.jpg)
And this is the other one to the north, which also operated permissively (https://goo.gl/maps/euQgF4NXKPVkPNmL8) (though with time-of-day phasing implemented in 2013), which has since been modified with an overpass:
(https://fanblogs.jp/oortcloud/file/undefined/E7AEB1E5A0A4E4BAA4E5B7AEE782B9.jpg)
In this tweet, the person actually states that they are afraid when turning right. However, I think the concern is more with the triple right turns, not that they were "free" right turns....
https://twitter.com/yujin0131rs/status/1324330141196021760
Lastly, someone made a YouTube video about it too. You can see it in permissive mode around 4:50 onwards, and then a timelapse at 8:00 (immediately preceded by a woman complaining about the length of the crossing)...
https://youtu.be/q9IvniFzRZU
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on June 19, 2023, 09:59:59 AM
Post by: jakeroot on June 19, 2023, 09:59:59 AM
The off-ramp from Westbound Ontario Route 403 to Trafalgar Road in Oakville has a dual left turn that is green simultaneous with the oncoming right turn; the oncoming single lane left turn is protected-only, however:
https://goo.gl/maps/wAA1jHrBPkG8dCPG6
https://goo.gl/maps/wAA1jHrBPkG8dCPG6
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on June 29, 2023, 05:18:30 AM
Post by: jakeroot on June 29, 2023, 05:18:30 AM
Quote from: jakeroot on May 26, 2023, 09:21:44 PMQuote from: fwydriver405 on May 25, 2023, 01:08:20 AMQuote from: jakeroot on May 01, 2023, 07:25:19 PM
I've been led to believe they are incredibly rare in Ontario and Quebec.
Poking around GSV, this left turn in Montréal (https://www.google.com/maps/@45.5084184,-73.5618962,3a,41.7y,31.65h,83.66t/data=!3m7!1e1!3m5!1s7p0OHo37tF8q2OzNelX_IQ!2e0!5s20140401T000000!7i13312!8i6656?hl=en) used to be double permissive (L-LT) up till around the summer of 2014. It is now protected only with only 1 turning lane since then and when I was there on a Friday and Saturday, there were long queues and some split failures at this left turn.
Nice find! Never seen one in Quebec before, to be honest. I was assuming they were rare as none have been brought up here before.
I find it odd they'd remove the outside turn lane (except for buses) and change it to protected-only. Seems like it could still operate permissively as it stands.
Found another one in Montreal:
https://goo.gl/maps/GPgAUCjCtYXBgiJz5
It has an option lane like the other examples from Quebec.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on August 24, 2023, 03:26:01 PM
Post by: fwydriver405 on August 24, 2023, 03:26:01 PM
Unsure if this counts, but this double (YoG-pt+pm) left turn in San Francisco is a bit strange - a dedicated left turning lane for bicycles (to turn into the protected bike lane), and a shared left-thru lane for motor vehicles (into the other lanes). Advanced green for NB Scott St, then the permissive phase for both approaches. The SB approach is thru-right for bikes, and right turn only for moter vehicle traffic. Scott and Fell Streets:
GSV: https://www.google.com/maps/@37.7739963,-122.4358715,3a,29.9y,349.72h,84.29t/data=!3m7!1e1!3m5!1sjiSDRsUVatHwIWzVwz99cQ!2e0!5s20220301T000000!7i16384!8i8192?entry=ttu
Overview: https://www.google.com/maps/@37.774189,-122.4359471,75m/data=!3m1!1e3?entry=ttu
GSV: https://www.google.com/maps/@37.7739963,-122.4358715,3a,29.9y,349.72h,84.29t/data=!3m7!1e1!3m5!1sjiSDRsUVatHwIWzVwz99cQ!2e0!5s20220301T000000!7i16384!8i8192?entry=ttu
Overview: https://www.google.com/maps/@37.774189,-122.4359471,75m/data=!3m1!1e3?entry=ttu
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on August 24, 2023, 06:06:43 PM
Post by: jakeroot on August 24, 2023, 06:06:43 PM
Quote from: fwydriver405 on August 24, 2023, 03:26:01 PM
Unsure if this counts, but this double (YoG-pt+pm) left turn in San Francisco is a bit strange - a dedicated left turning lane for bicycles (to turn into the protected bike lane), and a shared left-thru lane for motor vehicles (into the other lanes). Advanced green for NB Scott St, then the permissive phase for both approaches. The SB approach is thru-right for bikes, and right turn only for moter vehicle traffic. Scott and Fell Streets:
GSV: https://www.google.com/maps/@37.7739963,-122.4358715,3a,29.9y,349.72h,84.29t/data=!3m7!1e1!3m5!1sjiSDRsUVatHwIWzVwz99cQ!2e0!5s20220301T000000!7i16384!8i8192?entry=ttu
Overview: https://www.google.com/maps/@37.774189,-122.4359471,75m/data=!3m1!1e3?entry=ttu
I guess if it were up to this black Honda Accord (https://goo.gl/maps/xC4VYzPUsBZtduAYA), there wouldn't be any question that it qualifies!
I am actually willing to count this. It's really intriguing, I'm sure most places would have some kind of exclusive phasing for this approach instead of having it run concurrent with vehicular traffic.
It's almost like a purposeful version of a lane-split turn for a motorcyclist. Here in Japan, where like California it is also legal to ride between lanes of traffic, it's not unusual to be waiting to turn across traffic when a motorcyclist (usually scooter) will come up between traffic and wait next to you while you're also waiting to turn. It'll be a single lane turn (right turn in Japan), but it becomes a sort of double permissive turn with the motorcyclist also hanging out there in the middle waiting with you. As far as I can tell, that's basically what might happen in the SF example, although there is at least a designated cycle lane.
Title: Re: Double left turns with permissive phasing
Post by: jeffandnicole on August 25, 2023, 10:59:50 PM
Post by: jeffandnicole on August 25, 2023, 10:59:50 PM
Quote from: jakeroot on June 07, 2023, 04:43:04 AM
I did some research on Japan's "largest intersections", and it turns out the one most commonly cited is on National Route 4 (Sendai Bypass) at Miyagi Prefectural Route 137:
https://goo.gl/maps/5rq78gKtHQKhV4b19
Of note, the triple right turn lanes, until very recently, operated with permissive phasing (https://goo.gl/maps/2RvdebxVjVictdvc9). This intersection (as well as one to the north) are the only intersections anywhere in the world (that I've located so far) with directly-opposing triple turns that operated permissively.
The two intersections. This is the one mentioned in the tweet above:
(https://fanblogs.jp/oortcloud/file/undefined/E585ADE4B881E381AEE79BAEE4BAA4E5B7AEE782B9.jpg)
The turn lane queues on the triple lefts don't even appear they line up well with the receiving lane on the other side.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on August 25, 2023, 11:29:53 PM
Post by: jakeroot on August 25, 2023, 11:29:53 PM
Quote from: jeffandnicole on August 25, 2023, 10:59:50 PMQuote from: jakeroot on June 07, 2023, 04:43:04 AM
I did some research on Japan's "largest intersections", and it turns out the one most commonly cited is on National Route 4 (Sendai Bypass) at Miyagi Prefectural Route 137:
https://goo.gl/maps/5rq78gKtHQKhV4b19
Of note, the triple right turn lanes, until very recently, operated with permissive phasing (https://goo.gl/maps/2RvdebxVjVictdvc9). This intersection (as well as one to the north) are the only intersections anywhere in the world (that I've located so far) with directly-opposing triple turns that operated permissively.
The two intersections. This is the one mentioned in the tweet above:
(https://fanblogs.jp/oortcloud/file/undefined/E585ADE4B881E381AEE79BAEE4BAA4E5B7AEE782B9.jpg)
The turn lane queues on the triple lefts don't even appear they line up well with the receiving lane on the other side.
Indeed, the right turn lanes don't line up well at all. It's almost like you turn into the queue area, then go straight, and then make another slight right onto the receiving road.
It goes without saying that this would never work in the US, drivers would constantly end up in the wrong lane. And even for Japan, where drivers are substantially more aware of their surroundings than American or Canadian drivers, this is apparently a very intimidating intersection. Not least because it operated permissively, but also because of the huge neutral area (the area where turning traffic and through traffic cross over) that made it really hard to gauge when it was appropriate to, you know, 'go for it'. Which was certainly exacerbated by the very odd alignment of the turn lanes.
Title: Re: Double left turns with permissive phasing
Post by: jeffandnicole on August 25, 2023, 11:36:10 PM
Post by: jeffandnicole on August 25, 2023, 11:36:10 PM
Quote from: jakeroot on August 25, 2023, 11:29:53 PMQuote from: jeffandnicole on August 25, 2023, 10:59:50 PMQuote from: jakeroot on June 07, 2023, 04:43:04 AM
I did some research on Japan's "largest intersections", and it turns out the one most commonly cited is on National Route 4 (Sendai Bypass) at Miyagi Prefectural Route 137:
https://goo.gl/maps/5rq78gKtHQKhV4b19
Of note, the triple right turn lanes, until very recently, operated with permissive phasing (https://goo.gl/maps/2RvdebxVjVictdvc9). This intersection (as well as one to the north) are the only intersections anywhere in the world (that I've located so far) with directly-opposing triple turns that operated permissively.
The two intersections. This is the one mentioned in the tweet above:
(https://fanblogs.jp/oortcloud/file/undefined/E585ADE4B881E381AEE79BAEE4BAA4E5B7AEE782B9.jpg)
The turn lane queues on the triple lefts don't even appear they line up well with the receiving lane on the other side.
Indeed, the right turn lanes don't line up well at all...
Dammit. Yeah, triple rights.
Title: Re: Double left turns with permissive phasing
Post by: mrsman on September 01, 2023, 06:04:23 PM
Post by: mrsman on September 01, 2023, 06:04:23 PM
Quote from: jakeroot on August 24, 2023, 06:06:43 PMQuote from: fwydriver405 on August 24, 2023, 03:26:01 PM
Unsure if this counts, but this double (YoG-pt+pm) left turn in San Francisco is a bit strange - a dedicated left turning lane for bicycles (to turn into the protected bike lane), and a shared left-thru lane for motor vehicles (into the other lanes). Advanced green for NB Scott St, then the permissive phase for both approaches. The SB approach is thru-right for bikes, and right turn only for moter vehicle traffic. Scott and Fell Streets:
GSV: https://www.google.com/maps/@37.7739963,-122.4358715,3a,29.9y,349.72h,84.29t/data=!3m7!1e1!3m5!1sjiSDRsUVatHwIWzVwz99cQ!2e0!5s20220301T000000!7i16384!8i8192?entry=ttu
Overview: https://www.google.com/maps/@37.774189,-122.4359471,75m/data=!3m1!1e3?entry=ttu
I guess if it were up to this black Honda Accord (https://goo.gl/maps/xC4VYzPUsBZtduAYA), there wouldn't be any question that it qualifies!
I am actually willing to count this. It's really intriguing, I'm sure most places would have some kind of exclusive phasing for this approach instead of having it run concurrent with vehicular traffic.
It's almost like a purposeful version of a lane-split turn for a motorcyclist. Here in Japan, where like California it is also legal to ride between lanes of traffic, it's not unusual to be waiting to turn across traffic when a motorcyclist (usually scooter) will come up between traffic and wait next to you while you're also waiting to turn. It'll be a single lane turn (right turn in Japan), but it becomes a sort of double permissive turn with the motorcyclist also hanging out there in the middle waiting with you. As far as I can tell, that's basically what might happen in the SF example, although there is at least a designated cycle lane.
A bit of a weird one. I'd say that the bike left turn doesn't have to turn against car traffic, only against peds and oncoming bikes. If one were to ignore the oncoming bikes, this is like a left from one way to one way as the bikes make their left into the lane most adjacent to the curb on Fell. So really only the cars have to make a permissive left against traffic (opposing vehicles making the right from Scott to Fell).
A very unique example!
Title: Re: Double left turns with permissive phasing
Post by: andrepoiy on October 14, 2023, 12:47:40 PM
Post by: andrepoiy on October 14, 2023, 12:47:40 PM
Colorado Springs, CO:
(https://i.imgur.com/5QQyNwT.png)
Link: https://maps.app.goo.gl/Rj11AfwDRnW3sLu37
(https://i.imgur.com/5QQyNwT.png)
Link: https://maps.app.goo.gl/Rj11AfwDRnW3sLu37
Title: Re: Double left turns with permissive phasing
Post by: Big John on October 25, 2023, 12:48:11 PM
Post by: Big John on October 25, 2023, 12:48:11 PM
I just passed Lombardi Ave at I-41 where WisDOT is currently changing WB to SB dual left from turn on arrow only to a FYA.
Title: Re: Double left turns with permissive phasing
Post by: fwydriver405 on November 02, 2023, 06:21:20 PM
Post by: fwydriver405 on November 02, 2023, 06:21:20 PM
Found a brand new, double permissive FYA lagging left (with two left turn lanes) in Dorchester (Boston), Massachusetts at the intersection of Morrissey Blvd and Freeport St (https://www.google.com/maps/@42.3007897,-71.0494209,3a,75y,139.71h,85.79t/data=!3m6!1e1!3m4!1s8EIzUWg85yLbqJM-9LlAXA!2e0!7i16384!8i8192?entry=ttu) on the SB Freeport St approach. Not sure if this was a MassDOT or DCR installation, as they recently redid the intersection.
Unlike the other double permissive left on Atlantic Ave and Congress St (https://www.aaroads.com/forum/index.php?topic=17051.msg2450802#msg2450802), on the SB approach, where it's only double permissive left due to left turn on red, this one had a second left turn lane added and the PPLT phase retained via FYA. Unfortunately the NB Freeport St approach is yellow trapped, however I didn't get to get a chance to look at the opposing signals.
EDIT, photo and video of the intersection:
(https://i.ibb.co/17hBc2z/DSC00241.jpg) (https://ibb.co/HB1RZgh)
https://www.youtube.com/watch?v=j6d62fYJXEA
Unlike the other double permissive left on Atlantic Ave and Congress St (https://www.aaroads.com/forum/index.php?topic=17051.msg2450802#msg2450802), on the SB approach, where it's only double permissive left due to left turn on red, this one had a second left turn lane added and the PPLT phase retained via FYA. Unfortunately the NB Freeport St approach is yellow trapped, however I didn't get to get a chance to look at the opposing signals.
EDIT, photo and video of the intersection:
(https://i.ibb.co/17hBc2z/DSC00241.jpg) (https://ibb.co/HB1RZgh)
https://www.youtube.com/watch?v=j6d62fYJXEA
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on November 03, 2023, 12:35:58 AM
Post by: jakeroot on November 03, 2023, 12:35:58 AM
Quote from: fwydriver405 on November 02, 2023, 06:21:20 PM
Found a brand new, double permissive FYA lagging left (with two left turn lanes) in Dorchester (Boston), Massachusetts at the intersection of Morrissey Blvd and Freeport St (https://www.google.com/maps/@42.3007897,-71.0494209,3a,75y,139.71h,85.79t/data=!3m6!1e1!3m4!1s8EIzUWg85yLbqJM-9LlAXA!2e0!7i16384!8i8192?entry=ttu) on the SB Freeport St approach. Not sure if this was a MassDOT or DCR installation, as they recently redid the intersection.
Unlike the other double permissive left on Atlantic Ave and Congress St (https://www.aaroads.com/forum/index.php?topic=17051.msg2450802#msg2450802), on the SB approach, where it's only double permissive left due to left turn on red, this one had a second left turn lane added and the PPLT phase retained via FYA. Unfortunately the NB Freeport St approach is yellow trapped, however I didn't get to get a chance to look at the opposing signals.
EDIT, photo and video of the intersection:
[clipped]
Thank you for posting! This is one of the more interesting ones I've seen lately.
Some of the GSV imagery seems to suggest that some drivers were already turning left from the through lane (https://maps.app.goo.gl/uWQbYwcdcGNg927J8). Or possibly this was a permitted movement, and I just can't find any signage to prove it.
The new far-left signal is great. While I'm a proponent of making this standard for all approaches, it's nice they added it here as before, there was no visible signal while waiting.
While this is cool to see, especially with the markings in the intersection showing where drivers to wait when turning, the fact that NB Freeport is still allowed turn left onto Morrissey Blvd is quite odd. I would think detouring those cars via Mill or Everdean would create less of that unusual left turn overlap situation occurring in the video.
As an aside, I assume this is the only double permissive FYA setup in Massachusetts.
Title: Re: Double left turns with permissive phasing
Post by: jakeroot on March 28, 2024, 04:50:01 AM
Post by: jakeroot on March 28, 2024, 04:50:01 AM
Found a new triple permissive turn, though with a twist.
Outside of Fukuoka, Japan, in the city of Chikushino, there is a triple permissive right turn at the Harizuri Intersection (https://www.google.com/maps/@33.4829111,130.5381456,267m/data=!3m1!1e3?entry=ttu). The right two right-turn lanes make a 90-degree turn onto the ramp to National Route 3, whilst the left right-turn lane makes a shallower turn onto a local road (Fukuoka Prefectural Route 112).
As is tradition in Japan, at complex intersections, colors are used to guide traffic through. The lanes turning towards National Route 3 are blue, and the lane to Route 112 is green. Through traffic has red markings.
Apparently this intersection has a fairly high crash rate (https://www.sonpo.or.jp/about/useful/kousaten/2022/40/index.html) (intersection "D" on the list).
Here's my render showing how it flows:
(https://live.staticflickr.com/65535/53616499169_a406b71de5_k.jpg)
Harizuri Intersection, Chikushino (https://flic.kr/p/2pFUzet) by Jacob Root (https://www.flickr.com/photos/62537709@N03/), on Flickr
Outside of Fukuoka, Japan, in the city of Chikushino, there is a triple permissive right turn at the Harizuri Intersection (https://www.google.com/maps/@33.4829111,130.5381456,267m/data=!3m1!1e3?entry=ttu). The right two right-turn lanes make a 90-degree turn onto the ramp to National Route 3, whilst the left right-turn lane makes a shallower turn onto a local road (Fukuoka Prefectural Route 112).
As is tradition in Japan, at complex intersections, colors are used to guide traffic through. The lanes turning towards National Route 3 are blue, and the lane to Route 112 is green. Through traffic has red markings.
Apparently this intersection has a fairly high crash rate (https://www.sonpo.or.jp/about/useful/kousaten/2022/40/index.html) (intersection "D" on the list).
Here's my render showing how it flows:
(https://live.staticflickr.com/65535/53616499169_a406b71de5_k.jpg)
Harizuri Intersection, Chikushino (https://flic.kr/p/2pFUzet) by Jacob Root (https://www.flickr.com/photos/62537709@N03/), on Flickr
Title: Re: Double left turns with permissive phasing
Post by: Revive 755 on April 12, 2024, 10:47:34 PM
Post by: Revive 755 on April 12, 2024, 10:47:34 PM
WB 5th Street at MO 109 in Eureka has one. (https://maps.app.goo.gl/Fi48CdUENBmKjegs5)