Double left turns with permissive phasing

[jakeroot]

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

[bcroadguy]

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.

[jakeroot]

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.

[Roadwarriors79]

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

[kphoger]

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, in case anyone else, like me, didn't know at first what state you were even talking about.

[fwydriver405]

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.youtube.com/watch?v=RVqw1BuaXwY

[Big John]

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.

[zachary_amaryllis]

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
note car running red light.

[jeffandnicole]

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
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.

[roadman65]

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
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

[mrsman]

Found another in Chicago: https://goo.gl/maps/Zn42Wji2djFMVPdd9

This brings the Chicago area to three four known installations:

N Sheridan Road @ W Bryn Mawr Ave (option lane)
N Columbus Drive (NB) @ E Grand Ave (former option lane, now two dedicated turns) (NEW)
N Columbus Drive (SB) @ E Illinois Street (former option lane, now two dedicated turns) (NEW)
Thorndale Ave @ Park Blvd, Itasca (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 (option lane) (NEW)
E Monroe Street (EB) @ LSD (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.]

[JayhawkCO]

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; (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 just south of my house.  Had never really paid attention before.

[zachary_amaryllis]

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

[ran4sh]

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.

[fwydriver405]

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). 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

[Hobart]

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

[jakeroot]

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), and another leaving the cell phone lot at YVR (here).

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), so they are evidently committed to the permissive phasing:

https://youtu.be/65MP7m4qTtA

[Revive 755]

Based on Page 11 of 26 of these plans, 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").

[Hobart]

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.

[jakeroot]

Based on Page 11 of 26 of these plans, 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.

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.

[jakeroot]

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)

[ran4sh]

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).

[jakeroot]

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.

[Hobart]

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.

[jakeroot]

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.