Double left turns with permissive phasing

[jakeroot]

Another in New York City:

Kissena Blvd @ the LIE (I-495) (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) (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)

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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.

[SkyPesos]

Not really the same as the ones in this thread; it's quite the opposite but interesting.
At the Mexico and Jungermann intersection 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.

[jakeroot]

Not really the same as the ones in this thread; it's quite the opposite but interesting.
At the Mexico and Jungermann intersection 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 near me).

Before anyone else shares additional examples of split-phasing: remember that this thread is for permissive lefts, not protected lefts .

[fwydriver405]

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), Oct 2018 GSV (protected only?)

[jakeroot]

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), Oct 2018 GSV (protected only?)

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.

[RestrictOnTheHanger]

Another in New York City:

Kissena Blvd @ the LIE (I-495) (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) (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.

[Amtrakprod]

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), Oct 2018 GSV (protected only?)

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.

That's too bad. St Albans aint to far from me I'll check it out IRL sometime


iPhone

[jakeroot]

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.

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.

That's too bad. St Albans aint to far from me I'll check it out IRL sometime

If you can get over there late at night, see if it operates with time-of-day phasing.

[Amtrakprod]

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.

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.

That's too bad. St Albans aint to far from me I'll check it out IRL sometime

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 🤞

[RestrictOnTheHanger]

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.

[jakeroot]

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.

[mrsman]

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.

[jakeroot]

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:

Here's an image of a typical FYA setup (James St at 6th Ave, Seattle):

(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.

[mrsman]

(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.

[betfourteen]

Another Nassau County, NY find

Wantagh Ave & Old Jerusalem Rd https://goo.gl/maps/BDyFacd7pFBr2ZyZ6

[jakeroot]

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 to protected-only.

[jakeroot]

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

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 in this country (with exceptions, 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 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.

[RestrictOnTheHanger]

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 to protected-only.

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.

[betfourteen]

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)

[jakeroot]

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".

All of these examples must be the legacy of a few engineers. Or perhaps influence from New York City? It's very intriguing.

[betfourteen]

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".

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.

[betfourteen]

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: 
https://goo.gl/maps/Dg7UGrSQjDAYHu3F8

These intersections, and road in general, are horrific during the holiday season and on weekends.

[RestrictOnTheHanger]

Another one in Queens, with a bonus awkward left turn signal

Queens Blvd at Hillside Ave

https://maps.app.goo.gl/NvujbpSa8wSagBZp9

[kphoger]

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.

[jakeroot]

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:

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, which has open sightlines due to the way the WB ROW shifts).