Double left turns with permissive phasing

[CovalenceSTU]

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):


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):

[Hobart]

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!

[jakeroot]

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).

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)....it's just all really well done.

[Hobart]

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.

[jakeroot]

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.

[roadman65]

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.

[jakeroot]

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.

[fwydriver405]

Found an Ontario example of such double PPLT phasing in Cornwell, Ontario 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?

[jakeroot]

Found an Ontario example of such double PPLT phasing in Cornwell, Ontario 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.

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.

[RestrictOnTheHanger]

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

[jakeroot]

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.

[RestrictOnTheHanger]

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.

[fwydriver405]

I've been led to believe they are incredibly rare in Ontario and Quebec.

Poking around GSV, this left turn in Montréal 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.

[jakeroot]

I've been led to believe they are incredibly rare in Ontario and Quebec.

Poking around GSV, this left turn in Montréal 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.

[jakeroot]

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

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.

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 (alt view looking other way)

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 (spin camera around to see opposing green signal).

[andrepoiy]

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.




Link: https://goo.gl/maps/bLfCyfCD5iGQszzG8

[jakeroot]

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.




Link: https://goo.gl/maps/bLfCyfCD5iGQszzG8

Great find! Too bad it wasn't on better terms  . 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.

[jakeroot]

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. 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:



And this is the other one to the north, which also operated permissively (though with time-of-day phasing implemented in 2013), which has since been modified with an overpass:



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

[jakeroot]

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

[jakeroot]

I've been led to believe they are incredibly rare in Ontario and Quebec.

Poking around GSV, this left turn in Montréal 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.

[fwydriver405]

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

[jakeroot]

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, 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.

[jeffandnicole]

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. 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:

The turn lane queues on the triple lefts don't even appear they line up well with the receiving lane on the other side.

[jakeroot]

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. 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:

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.

[jeffandnicole]

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. 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:

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.