Protected Turns with no Designated Turn Lane

[webny99]

What examples are there of a signal having a protected phase for a turn movement (left or right) but no designated lane for that movement?

I know of two that happen to be just a couple miles apart:

1) Salt Rd at NY 404 - left turn arrow but no left turn lane. This is because Ridge Road is set on, you guessed it, a bit of a ridge, which causes limited visibility on Salt Rd on either side of the intersection. So the signal is programmed with three phases: Ridge Rd (both directions), Salt Rd (southbound ONLY - all movements), Salt Rd (northbound ONLY - all movements).

2) NY 250 at NY 404* - right turn arrow but no right turn lane. Never seen this anywhere else, but it basically overrides the "no turn on red" and allows traffic to turn right during NY 404's protected left phase. Obviously, it serves no purpose when the first car in line is going straight, so it's somewhat fluky, but it can reduce delays if a string of cars happen to all be turning right.




* Note the erroneous US 404 shields, which have since been replaced.

[7/8]

Two close together examples for lefts are northbound Regina St at Bridgeport Rd and southbound Regina St at Erb St. in Waterloo, ON.

Here's a four-lane road example: eastbound Fairway Rd at Morgan Ave in Kitchener, ON.

[kphoger]

approach 1
approach 2

[Big John]

There are a couple in downtown Green Bay plus 3 other locations.

FYI, FYAs aren't allowed to be used in this situation.

[1995hoo]

Not sure if this qualifies, and I believe the intersection in question was restriped earlier this year to eliminate the situation: Eastbound Constitution Avenue at 18th Street NW in DC for many, many years had one dedicated left-turn lane and one option lane that went straight or left, but the green arrow was independent of the straight-ahead light and left-turning traffic would have a red arrow while straight-thru traffic had a green. You can imagine the trouble that would cause if someone wanted to go left from the option lane and came to a stop because the red arrow was on.

(Most people didn't turn left from that lane. A bigger problem was that a lot of people went straight from the left-turn-only lane. I'm sure all that was one major reason why they finally restriped the eastbound lanes. I've only been through there once in the past few months and I was going the other way, so I didn't get a very good look at what they did.)

[ran4sh]

What examples are there of a signal having a protected phase for a turn movement (left or right) but no designated lane for that movement?

I know of two that happen to be just a couple miles apart:

1) Salt Rd at NY 404 - left turn arrow but no left turn lane. This is because Ridge Road is set on, you guessed it, a bit of a ridge, which causes limited visibility on Salt Rd on either side of the intersection. So the signal is programmed with three phases: Ridge Rd (both directions), Salt Rd (southbound ONLY - all movements), Salt Rd (northbound ONLY - all movements).

2) NY 250 at NY 404* - right turn arrow but no right turn lane. Never seen this anywhere else, but it basically overrides the "no turn on red" and allows traffic to turn right during NY 404's protected left phase. Obviously, it serves no purpose when the first car in line is going straight, so it's somewhat fluky, but it can reduce delays if a string of cars happen to all be turning right.




* Note the erroneous US 404 shields, which have since been replaced.

There are several of these in the Athens, GA area for some reason.

* Still exists https://goo.gl/maps/39UrW6PUQHa3uYnM8
* From this spot you can see two separate instances of this. The one the camera is facing, and then turn around 180 degrees and there's another one. https://goo.gl/maps/U5GG126zavnCeWbd6

* It used to be even worse, here are a couple that existed when the road was striped with 4 lanes (2 each direction). These locations only got designated turn lanes when the road was restriped to 2 lanes with center 2-way turn lane and bike lanes: https://goo.gl/maps/Wx4KX7jYRSaMJeJ39
https://goo.gl/maps/6o4CUwMZaahkZdtv7 <- Note that for this example, only the direction the camera is facing (westbound) had the protected left turn with the 4 lane configuration. The opposite direction did not have a protected left when the road was configured with 4 lanes.

[ran4sh]

There are a couple in downtown Green Bay plus 3 other locations.

FYI, FYAs aren't allowed to be used in this situation.

The reason is because during a phase when straight-through traffic has a red light, showing a flashing yellow arrow for left turns could result in a left-turning car crossing the center line to go around a car in front, in order to turn left.

[Dirt Roads]

Mentioned this one several times in other threads:  NC-86 northbound at I-85 Exit 165.  I'm pretty sure that this ramp was equipped with signals for quite some time, then modified to include a protected left turn after the Super WalMart was completed in Hampton Pointe in late August 2003 (and a signal installed at the opposite ramp with no protected left phase).  Soon after NCDOT adopted the FYLA approach about 6 or 7 years ago, this signal was modified accordingly.  At some point after, I noticed that this signal dropped the protected left functionality during most of the day with a time-of-day protected left after 4PM.  More recently, the time-of-day protected left was changed to 3:30PM. 

Walmart traffic heading back into Hillsborough tends to back up across the Interstate bridge (sometimes blocking left turn access to the other ramp) just a bit prior to the activation of the protected left, and it gets to near gridlock status after 5PM when more folks are getting onto the Interstate to commute west.  Most days, the traffic is backed up to the Hampton Pointe signal and sometimes it backs up all the way to the signal at Old Number 10.  Fortunately, Old Number 10 is now being used as part of a cobblestone bypass around the east side of Hillsborough, so most folks head over to take the Lawrence Road overpass when the traffic gets that bad.

[webny99]

Not sure if this qualifies, and I believe the intersection in question was restriped earlier this year to eliminate the situation: Eastbound Constitution Avenue at 18th Street NW in DC for many, many years had one dedicated left-turn lane and one option lane that went straight or left, but the green arrow was independent of the straight-ahead light and left-turning traffic would have a red arrow while straight-thru traffic had a green. You can imagine the trouble that would cause if someone wanted to go left from the option lane and came to a stop because the red arrow was on.

Sure, option lanes certainly qualify. I do recall this intersection being mentioned before, and when I looked at it just now, I almost thought it was unsignalized until I found the signals. Standard mounted signals would have allowed for supplementary lane signage to be posted, but I guess that's a non-issue now if it's been re-striped.

[Amtrakprod]

Not the exact same situation, but a shared right turn and bus lane with a protected right turn.


iPhone

[mrsman]

Not sure if this qualifies, and I believe the intersection in question was restriped earlier this year to eliminate the situation: Eastbound Constitution Avenue at 18th Street NW in DC for many, many years had one dedicated left-turn lane and one option lane that went straight or left, but the green arrow was independent of the straight-ahead light and left-turning traffic would have a red arrow while straight-thru traffic had a green. You can imagine the trouble that would cause if someone wanted to go left from the option lane and came to a stop because the red arrow was on.

(Most people didn't turn left from that lane. A bigger problem was that a lot of people went straight from the left-turn-only lane. I'm sure all that was one major reason why they finally restriped the eastbound lanes. I've only been through there once in the past few months and I was going the other way, so I didn't get a very good look at what they did.)

Do you know if at the time when you drove by here regularly if the eastbound green was a perpetual green?  It would seem that at no point in time would there be any conflicting traffic or pedestrians crossing at this corner, so eastbound straight traffic could have a constant green. 

[There used to be a perpetual green on Pennsylvania eastbound at the further intersection with Constitution. (given the angle it operates like two separate intersections)  Pretty much a similar configuration with a one-way outbound left turn at a T-intersection with no conflicting pedestrian movements.  Like the above intersection, a normal RYG signal for the green light instead of a one-aspect green that is common in other states.  Pennsylvania/Constitution is no longer perpetual green, because the bike lane uses the same signals as eastbound traffic and since the bike lane conflicts with the left turns, straight traffic also stops.]

I can tell you that over the last few years, DC has become more restrictive with turns in the names of pedestrian safety.  Many more NTOR signs.  Double turns are generally discouraged, unless there is a totally separate phase for conflicting pedestrian movements.  I don't know if anything like that was planned for here, but it wouldn't surprise me.

Here's a link:  https://ddot.dc.gov/page/intersections-dual-turn-lanes

Since I worked regularly near Constitution before COVID, I have thought of some plans to make the street more efficient.  To me, it seemed unfortunate that a street that was 8 lanes wide could not have a consistent left turn lane.  It would certainly be safer than having left lane traffic stop suddenly just because someone wanted to turn left.

[andrepoiy]

I feel like this type of configuration is common in some older and downtown areas of Ontario towns. Occurs when they're usually only 4 lanes with no room to add a turn lane, and there's enough turning traffic to warrant it.

Some examples:

Stratford ON:


Cambridge ON:


Toronto ON:

[1995hoo]

Not sure if this qualifies, and I believe the intersection in question was restriped earlier this year to eliminate the situation: Eastbound Constitution Avenue at 18th Street NW in DC for many, many years had one dedicated left-turn lane and one option lane that went straight or left, but the green arrow was independent of the straight-ahead light and left-turning traffic would have a red arrow while straight-thru traffic had a green. You can imagine the trouble that would cause if someone wanted to go left from the option lane and came to a stop because the red arrow was on.

(Most people didn't turn left from that lane. A bigger problem was that a lot of people went straight from the left-turn-only lane. I'm sure all that was one major reason why they finally restriped the eastbound lanes. I've only been through there once in the past few months and I was going the other way, so I didn't get a very good look at what they did.)

Do you know if at the time when you drove by here regularly if the eastbound green was a perpetual green?  ....

It was definitely not a perpetual green–this Street View image shows a red light.

[jmacswimmer]

The DC example above reminds me of this one out of Baltimore: Westbound Lombard St at Light St, where there is a triple left but the rightmost left-turn lane can also go thru.

The left-turn signal changes to green on a lag compared to the straight green, in order to give pedestrians a chance to cross before getting obliterated by 3 lanes of heavy turning traffic.  Which leads to the same situation 1995hoo describes where someone going straight in the left thru lane/rightmost left-turn lane could get caught behind someone waiting for the left.  (And I've seen it happen before - usually the vehicle trying to go straight realizes their situation after a second, and tries to change lanes to the right and go around.)

[jeffandnicole]

What examples are there of a signal having a protected phase for a turn movement (left or right) but no designated lane for that movement?

I know of two that happen to be just a couple miles apart:

1) Salt Rd at NY 404 - left turn arrow but no left turn lane. This is because Ridge Road is set on, you guessed it, a bit of a ridge, which causes limited visibility on Salt Rd on either side of the intersection. So the signal is programmed with three phases: Ridge Rd (both directions), Salt Rd (southbound ONLY - all movements), Salt Rd (northbound ONLY - all movements).

This is split phasing and is fairly common in areas where there isn't enough room for turning lanes, sight distance for opposing traffic at the intersection, or there's a heavy turning movement that justifies a thru/turn lane

2) NY 250 at NY 404* - right turn arrow but no right turn lane. Never seen this anywhere else, but it basically overrides the "no turn on red" and allows traffic to turn right during NY 404's protected left phase. Obviously, it serves no purpose when the first car in line is going straight, so it's somewhat fluky, but it can reduce delays if a string of cars happen to all be turning right.

Fsr more uncommon for the reason you mentioned. 95 South in Baltimore...just after the Harbor Tunnel is Exit 55, Key Highway. The first traffic light has this function.
https://maps.app.goo.gl/XSk42xs93tfT9xwt9

[ran4sh]

Split phasing can also be used where a traffic signal progression (coordination) plan justifies it, i.e. when the platoons of traffic from opposite directions reach the signal at different times, but that is not as common as the other uses.

[webny99]

This is split phasing and is fairly common in areas where there isn't enough room for turning lanes, sight distance for opposing traffic at the intersection, or there's a heavy turning movement that justifies a thru/turn lane

It's not very common around here, but all of the factors you mention are more common closer to the east coast, so it makes sense that it would be more common there.

(And if you're not familiar with a particular intersection, you wouldn't necessarily know whether the light just went green + green arrow on that particular cycle (when there's no opposing traffic waiting to turn left, for example) or whether it's actually programmed that way permanently, so it's entirely possible there's more around that I'm not aware of.)

[webny99]

I just thought of something else... what about intersections where all four approaches have their own phase? No specific protected phases, just four different phases, one for each direction. That's how this intersection (NY 64/Stone Rd/Mendon Center Rd) is programmed. In this case, it's pretty obvious why; the "K" alignment makes it so that there's no clear "straight" movement in any given direction.

[ran4sh]

This is split phasing and is fairly common in areas where there isn't enough room for turning lanes, sight distance for opposing traffic at the intersection, or there's a heavy turning movement that justifies a thru/turn lane

It's not very common around here, but all of the factors you mention are more common closer to the east coast, so it makes sense that it would be more common there.

(And if you're not familiar with a particular intersection, you wouldn't necessarily know whether the light just went green + green arrow on that particular cycle (when there's no opposing traffic waiting to turn left, for example) or whether it's actually programmed that way permanently, so it's entirely possible there's more around that I'm not aware of.)

It's always programmed that way permanently, because even if there is a detector in the lane, it has no way to tell whether the car wants to go straight or left if both are legal movements. Maybe if it's a multilane road and a car is detected in the right lane but not the left, but I'm not sure they would go through the hassle of programming those lanes separately.

If you're referring to the possibility that the protected left is a lagging phase (the oncoming thru traffic goes first), that is usually avoided because it causes yellow trap for oncoming traffic wanting to turn left.

[webny99]

This is split phasing and is fairly common in areas where there isn't enough room for turning lanes, sight distance for opposing traffic at the intersection, or there's a heavy turning movement that justifies a thru/turn lane

It's not very common around here, but all of the factors you mention are more common closer to the east coast, so it makes sense that it would be more common there.

(And if you're not familiar with a particular intersection, you wouldn't necessarily know whether the light just went green + green arrow on that particular cycle (when there's no opposing traffic waiting to turn left, for example) or whether it's actually programmed that way permanently, so it's entirely possible there's more around that I'm not aware of.)

It's always programmed that way permanently, because even if there is a detector in the lane, it has no way to tell whether the car wants to go straight or left if both are legal movements. Maybe if it's a multilane road and a car is detected in the right lane but not the left, but I'm not sure they would go through the hassle of programming those lanes separately.

Yes, it's always that way if there's a shared lane, but as to the second half of my comment, I was referring to the presence of split phasing more generally, not just at intersections with no designated turn lanes.

[DrSmith]

On Boylston St in Boston, heading outbound at the intersection with Park in Fenway there is this signal.
Two lanes with no dedicated turn lane. The left turn lane has a permitted left phase.
It's a dedicated phase, although either holds up through traffic when it's red for left turners.
Or it holds up left turners who get behind through traffic.

https://goo.gl/maps/11UiNHfQdU4oRbMi9
A different view with the left turn signal active
https://goo.gl/maps/zZzooae9Ao7d8kH86

[Mr_Northside]

This is pretty common here in SW PA.   Like some other examples given, it's mostly just old roads with no room to add any kind of dedicated turn lane but they'll add an arrow to a signal (or sometimes a doghouse) if turning traffic waiting on oncoming traffic is creating too much of a problem.

A random example:  https://goo.gl/maps/pLv2HD8mAYbPS5ZYA    (It looks like this whole intersection had a signal replacement (including new poles) between 2019 & 2021 so it's a doghouse now instead of just a 4-head)

(Not really on-topic, but if you navigate to the next intersection, with NO left-turn signal head, but that 4-lane road with no turn lanes, this is THE WORST place to encounter someone who doesn't use their left turn signal (at first).  By which I mean, you'll be in the left lane behind someone approaching the signal when it's red (or turning red) - the right lane is clear, but the vehicle in front doesn't have their turn signal on, so I figure there's no reason to get over cause they won't have to yield to oncoming traffic when it turns green (cause they're apparently not turning).   Meanwhile the right lane queues up deep.  The signals turn green, but the car in front doesn't start moving.  After a few moments (and maybe a horn honk) - THEN the driver puts on his left turn signal.... and the right lane is so full that you/I can't get over to go around without causing an accident.   I've had times where this has happened and there was enough oncoming traffic that I got stuck thru a whole new light cycle .  I feel in this instance, a person should be allowed to take a bat and smash said turn signal light to bits.  /END RANT )

[ran4sh]

It's always programmed that way permanently, because even if there is a detector in the lane, it has no way to tell whether the car wants to go straight or left if both are legal movements. Maybe if it's a multilane road and a car is detected in the right lane but not the left, but I'm not sure they would go through the hassle of programming those lanes separately.

I just remembered that, at intersections with a traffic signal, it's normal for the major road to not have detection for straight-through traffic (the signal is programmed to always assume such traffic exists). So sometimes in cases like this where there's a protected left without a protected left-turn lane, a detector will be installed in the left lane only, so that if a car is in the right lane, it does not trigger the left turn arrow. (However, a car going straight from the shared left-thru lane would still trigger the arrow)

[jakeroot]

Quite a lot of these around Vancouver, BC.

Here is an example northbound on Oak St at Douglas, a semi-popular left turn for traffic from BC-99 heading to downtown. I believe it skips green arrows between cycles; usually at least two, maybe three cars will turn on red, so there is always some capacity even when southbound Oak St is totally jammed.

[UCFKnights]

There are a couple in downtown Green Bay plus 3 other locations.

FYI, FYAs aren't allowed to be used in this situation.

Here's an example of a FYA without a designated lane in Florida:
https://www.google.com/maps/@29.6381607,-82.3459277,3a,90y,320.32h,84.73t/data=!3m7!1e1!3m5!1szn_jE47iDFMbMCuRalMnKw!2e0!5s20210301T000000!7i13312!8i6656

Note, this light doesn't contain a green arrow, only a FYA in the bottom position, it always flashes yellow while the green ball is displayed no matter what. I think its purpose is to remind people to yield to the cars going straight, almost everyone turns at this intersection with the rare car or 2 going straight, so when someone goes straight, those turning left often doesn't slow down and can go right in the path of the car with the actual ROW. I think its been effective at that.