LADOT Night time flash.. but not how you would expect.

[Amtrakprod]

https://www.youtube.com/watch?v=P5Zx_M-ZpQQ

We've all heard of nighttime flash, but in LA, a flashing yellow will replace a normal green at night.

[UCFKnights]

That is the typical installation of night flash from what I've seen in Florida... major road gets flashing yellow, minor road and turns get flashing red.

Although night flash has been disappearing almost everywhere because pedestrians signals turn off during it and for improved safety its a real easy programming change.

When I was young I remember all the business parks and schools near me would go to night flash fairly early... like 7pm. Infact one of my schools had a switch that allowed them to turn on and off the speed limit flashers along with the entry traffic light between flash/normal operation.

[nexus73]

Downtown Coos Bay OR used to have the same deal.  Given how light the traffic was after 10 PM, which is when the flashing lights kicked in, this was a good setup.  Then someone got a hair up their you know what and changed the signals back to red/yellow/green on a 24 hour basis. 

Rick

[Amtrakprod]

That is the typical installation of night flash from what I've seen in Florida... major road gets flashing yellow, minor road and turns get flashing red.

Although night flash has been disappearing almost everywhere because pedestrians signals turn off during it and for improved safety its a real easy programming change.

When I was young I remember all the business parks and schools near me would go to night flash fairly early... like 7pm. Infact one of my schools had a switch that allowed them to turn on and off the speed limit flashers along with the entry traffic light between flash/normal operation.

I don't think you understand. Here the traffic lights still operate in normal sequencing, but the green indication is replaced with a flashing yellow. The flashing yellow replaces the solid green.

Example:
During daytime:
Green for 30 seconds, Yellow for 3.5, Red for 20.
During Night:
Flashing Yellow for 30 seconds, Solid Yellow for 3.5, Red for 20.

[wanderer2575]

That is the typical installation of night flash from what I've seen in Florida... major road gets flashing yellow, minor road and turns get flashing red.

Although night flash has been disappearing almost everywhere because pedestrians signals turn off during it and for improved safety its a real easy programming change.

When I was young I remember all the business parks and schools near me would go to night flash fairly early... like 7pm. Infact one of my schools had a switch that allowed them to turn on and off the speed limit flashers along with the entry traffic light between flash/normal operation.

I don't think you understand. Here the traffic lights still operate in normal sequencing, but the green indication is replaced with a flashing yellow. The flashing yellow replaces the solid green.

Example:
During daytime:
Green for 30 seconds, Yellow for 3.5, Red for 20.
During Night:
Flashing Yellow for 30 seconds, Solid Yellow for 3.5, Red for 20.

The video is useless because it doesn't actually show that sequence (except way in the background at 00:36, and I had to watch it a dozen times before I finally saw that).  I don't understand how this is supposed to be safer for pedestrians.  Motorists unfamiliar with the setup wouldn't be expecting a solid yellow; seems to me that makes it more likely they will blow through a solid yellow or red.  Put this in the "confusion fail" bucket with HAWK signals.

[hotdogPi]

Why can't you use a standard nighttime flashing yellow/red but still have the pedestrian pushbuttons work normally?

[Revive 755]

I don't see the benefit from this sequence.  If they are going to have the main street be a flashing yellow, the side street should get a flashing red.  Otherwise they should stick with using circular green on the main street.

I don't think this complies with the MUTCD either.

[RobbieL2415]

I don't think that sequence is legal here.  Signals in CT must, by statute, always be green-yellow-red.

[roadfro]

Why can't you use a standard nighttime flashing yellow/red but still have the pedestrian pushbuttons work normally?

Pedestrian operation is incompatible with standard red/yellow flash since that essentially operates as a two-way stop intersection.

For example, if you're a pedestrian wanting to cross the major road that's facing the flashing red. If the push button were to give you a walk signal, it would have to be across the major streets flashing yellow. Those are conflicting indications.

The only way to have pedestrian push buttons work during red/yellow flash is if the push button forced the signal to temporarily transition to stop-and-go mode to accommodate the pedestrian crossing phase.

I don't see the benefit from this sequence.  If they are going to have the main street be a flashing yellow, the side street should get a flashing red.  Otherwise they should stick with using circular green on the main street.

I don't think this complies with the MUTCD either.

I agree. This isn't MUTCD compliant per section 4D.30p06, which prohibits any steady signal indication during flashing operations (except for continuously-lit single green arrows for protected continuous movements).

[mrsman]

THe new L.A. is not like the old L.A.

I agree that I don't see the benefit of this.  If the side street is normal and the main street changes from FY-Y-R, why not just keep it as green?

The only benefit to the FY is that it converts the signal to (effectively) a main street without yielding and a side street with stop signs.  While slightly less safe than regular signalization, it is more efficient especially when traffic is low.  But, that is not what is taking place here.



What would be interesting is a late-night only HAWK type signal.  Regular operation R-Y-G during busy hours.  During late night, HAWK like operation.  This would mean FY for N Broadway and FR for side streets during the late night period (which is equivalent to a regular 2-way stop sign intersectioin or HAWK when HAWK is off).  However, the pedestrian buttons (and only the pedestrian buttons) can be used to activate the signal to reach a solid red for N Broadway and a green for cross traffic and pedestrians.

While nighttime flash is common in many areas, it really isn't prevalent in L.A.  Unfortunately, they are implementing it wrong.

[RG407]

I don't think this complies with the MUTCD either.

I agree. This isn't MUTCD compliant per section 4D.30p06, which prohibits any steady signal indication during flashing operations (except for continuously-lit single green arrows for protected continuous movements).

Since when does California follow the rules?

[Roadrunner75]

Motorists unfamiliar with the setup wouldn't be expecting a solid yellow; seems to me that makes it more likely they will blow through a solid yellow or red.  Put this in the "confusion fail" bucket with HAWK signals.

Agree with this.  I can't stand the HAWK signals that are popping up around here too.  Like this flashing yellow during regular operation, the HAWKs are an unexpected signal change and are confusing to motorists.  Besides watching people blow through them because they weren't expecting a signal there, everyone who did manage to stop then sits at the alternating red flashing phase with no pedestrians because they were taught to do so at railroad crossings.  Traffic signals need to be consistent and operate in an expected manner to be effective.

[jakeroot]

Obviously, this is being implemented to improve night-time pedestrian collisions. The flashing yellow orbs are meant to draw the attention of drivers more than a standard green orb, especially since the former ostensibly requires you to stop and give way to pedestrians, whereas the latter does not (short of intentionally hitting a pedestrian). These intersections would still have active crosswalk signals, but the flashing yellow is probably trying to reduce instances of drivers hitting pedestrians who are crossing against solid "don't walk" signals. Yes, the pedestrian is in "the wrong", but they're still (potentially) dead, and not helping LADOT's Vision Zero goal.

These are not MUTCD-compliant, but I've always thought that was kind of a dumb metric since a lot of road improvements over the last fifty years likely weren't MUTCD-compliant either. Things are "not compliant" until they are proven to be worthy of compliance. Clearly LA has the money to study this phasing; if it's successful, I'm sure they could petition the FHWA to modify the relevant MUTCD section.

[Roadrunner75]

Besides causing confusion to drivers, it will probably cause confusion to pedestrians.  If they see that the main street has a flashing yellow, they may assume that the crosswalk signals are not active, and just walk across.  Drivers on the side street may also see the flashing yellow, assume something is wrong with the signal, that they need to treat it as a standard stop condition and then proceed on the red light.  The only way to handle these "not compliant" situations if they are going to use them is to have good signage.   The HAWK signal installations I have seen do not have good signage, which leads to everyone sitting there during the alternating reds.

I doubt the flashing yellow setup in LA is going to get people to use caution and slow down.  People treat flashing yellow like there is no signal at all.  When there's a green light, drivers will at least be prepared for the possibility the signal will change.  I think this could potentially lead to more accidents.

[mrsman]

Obviously, this is being implemented to improve night-time pedestrian collisions. The flashing yellow orbs are meant to draw the attention of drivers more than a standard green orb, especially since the former ostensibly requires you to stop and give way to pedestrians, whereas the latter does not (short of intentionally hitting a pedestrian). These intersections would still have active crosswalk signals, but the flashing yellow is probably trying to reduce instances of drivers hitting pedestrians who are crossing against solid "don't walk" signals. Yes, the pedestrian is in "the wrong", but they're still (potentially) dead, and not helping LADOT's Vision Zero goal.

These are not MUTCD-compliant, but I've always thought that was kind of a dumb metric since a lot of road improvements over the last fifty years likely weren't MUTCD-compliant either. Things are "not compliant" until they are proven to be worthy of compliance. Clearly LA has the money to study this phasing; if it's successful, I'm sure they could petition the FHWA to modify the relevant MUTCD section.

SO I guess what you're saying is that this recognizes the reality.  Late at night, pedestrians will be crossing North Broadway whenever they want, so it is safer if drivers treat the intersection as a two-way (side street) stop sign intersection, rather than a normal signalized intersection.  Drivers seeing a flashing yellow should expect crossing pedestrians in the same manner as a non-signalized intersection with side street stop signs, drivers seeing a green light would simply go and run them down.  Of course, pedestrians can still push the button to get a protected WALK signal against a solid red, but few actually do that during this time frame. 

I am very skeptical and not a fan of the arrangement.  The pedestrians should wait until it is safe to cross and wait for their WALK signal.

[roadfro]

Besides causing confusion to drivers, it will probably cause confusion to pedestrians.  If they see that the main street has a flashing yellow, they may assume that the crosswalk signals are not active, and just walk across.  Drivers on the side street may also see the flashing yellow, assume something is wrong with the signal, that they need to treat it as a standard stop condition and then proceed on the red light.  The only way to handle these "not compliant" situations if they are going to use them is to have good signage.   The HAWK signal installations I have seen do not have good signage, which leads to everyone sitting there during the alternating reds.

I doubt the flashing yellow setup in LA is going to get people to use caution and slow down.  People treat flashing yellow like there is no signal at all.  When there's a green light, drivers will at least be prepared for the possibility the signal will change.  I think this could potentially lead to more accidents.

There's a flaw in the first premise. If you watch the video, you can see that the "walk" signal is on while the adjacent flashing yellow is on, which implies the side street seeing red would also be seeing the upraised hand for pedestrians. (Which, by the way, is another non-compliance issue: MUTCD 4E.06p01 requires pedestrian signal indications to not be displayed when signals are in flashing mode.)

Obviously, this is being implemented to improve night-time pedestrian collisions. The flashing yellow orbs are meant to draw the attention of drivers more than a standard green orb, especially since the former ostensibly requires you to stop and give way to pedestrians, whereas the latter does not (short of intentionally hitting a pedestrian). These intersections would still have active crosswalk signals, but the flashing yellow is probably trying to reduce instances of drivers hitting pedestrians who are crossing against solid "don't walk" signals. Yes, the pedestrian is in "the wrong", but they're still (potentially) dead, and not helping LADOT's Vision Zero goal.

These are not MUTCD-compliant, but I've always thought that was kind of a dumb metric since a lot of road improvements over the last fifty years likely weren't MUTCD-compliant either. Things are "not compliant" until they are proven to be worthy of compliance. Clearly LA has the money to study this phasing; if it's successful, I'm sure they could petition the FHWA to modify the relevant MUTCD section.

Your rationale makes sense. But it would be more preferable to use some kind of operation that is compliant unless there's a compelling reason not to, which I don't see here. The greater problem is getting pedestrians to actually press a button and cross legally with the light.

Complying with the MUTCD is a bit of a safeguard for agencies against potential litigation and liability. If an agency installs non-compliant traffic control devices and there is an incident, the agency could be held (partially) responsible for the situation. That could be an issue with the LA setup, especially as they are out of compliance with two standards. Now if an agency wants to experiment with something that isn't quite in compliance, there's an experimentation process for that–this prompts additional review and study, to vet potential issues. This process is how we ended up with several initially non-compliant improvements/innovations, like RRFBs and HAWK signals.

[Roadrunner75]

There's a flaw in the first premise. If you watch the video, you can see that the "walk" signal is on while the adjacent flashing yellow is on, which implies the side street seeing red would also be seeing the upraised hand for pedestrians.

No, I assumed that the walk signals were working.  A pedestrian walking up would see the "Don't Walk" signal but also possibly the flashing yellow signal on the main street.  Since they would assume it's on a regular night-time flash, they might assume the walk signal is not functioning (i.e. will not change to "walk") and just treat it as such and go ahead and cross the street.  The average pedestrian is not going to know that the pedestrian signal is supposed to be dark during the regular flash mode.  If they walked up and saw the signal functioning normally, they would probably be more likely to assume they can push the button (if equipped) and wait for the walk signal.

[hotdogPi]

There are some signals in Massachusetts that are in permanent flash mode with ped signals. (Some of these are fire station signals that happen to include push buttons.)

[mrsman]

A little quick internet research on this does indicate that this pilot is part of a "vision zero" pedestrian safety initiative.  But as others discussed upthread, I don't believe it will lead to a safer situation along this stretch of road.

[Roadrunner75]

There are some signals in Massachusetts that are in permanent flash mode with ped signals. (Some of these are fire station signals that happen to include push buttons.)

Do they function like what is described above?  Are the pedestrian signals active and will they temporarily kick the signal into normal operation for the pedestrian crossing?

[jakeroot]

There's a flaw in the first premise. If you watch the video, you can see that the "walk" signal is on while the adjacent flashing yellow is on, which implies the side street seeing red would also be seeing the upraised hand for pedestrians. (Which, by the way, is another non-compliance issue: MUTCD 4E.06p01 requires pedestrian signal indications to not be displayed when signals are in flashing mode.)

But the intersection is not operating in flashing mode. This is a brand new mode apparently invented by the LADOT where the green is simply replaced by a flashing yellow. Otherwise it's identical to a regular signal (even if it's non-compliant in using that flashing yellow).

Obviously, this is being implemented to improve night-time pedestrian collisions. The flashing yellow orbs are meant to draw the attention of drivers more than a standard green orb, especially since the former ostensibly requires you to stop and give way to pedestrians, whereas the latter does not (short of intentionally hitting a pedestrian). These intersections would still have active crosswalk signals, but the flashing yellow is probably trying to reduce instances of drivers hitting pedestrians who are crossing against solid "don't walk" signals. Yes, the pedestrian is in "the wrong", but they're still (potentially) dead, and not helping LADOT's Vision Zero goal.

These are not MUTCD-compliant, but I've always thought that was kind of a dumb metric since a lot of road improvements over the last fifty years likely weren't MUTCD-compliant either. Things are "not compliant" until they are proven to be worthy of compliance. Clearly LA has the money to study this phasing; if it's successful, I'm sure they could petition the FHWA to modify the relevant MUTCD section.

Your rationale makes sense. But it would be more preferable to use some kind of operation that is compliant unless there's a compelling reason not to, which I don't see here. The greater problem is getting pedestrians to actually press a button and cross legally with the light.

Complying with the MUTCD is a bit of a safeguard for agencies against potential litigation and liability. If an agency installs non-compliant traffic control devices and there is an incident, the agency could be held (partially) responsible for the situation. That could be an issue with the LA setup, especially as they are out of compliance with two standards. Now if an agency wants to experiment with something that isn't quite in compliance, there's an experimentation process for that–this prompts additional review and study, to vet potential issues. This process is how we ended up with several initially non-compliant improvements/innovations, like RRFBs and HAWK signals.

I don't know if getting pedestrians to "press a button" should be the goal here. These Vision Zero programs generally put the burden on drivers to not hit pedestrians, rather than keeping pedestrians from getting hit by cars. This is largely because, unlike driving, you don't need a licence to walk. The onus is on drivers to operate their vehicle responsibly, and never hit a pedestrian if at all possible. Pedestrians are stupid, so forcing them to jump through hoops just to cross a street is not exactly a wise path forward. You might say pressing a button isn't much of a hoop; maybe, maybe not. But the operation of intersections, which clearly favours cars, does tend to force pedestrians to get impatient and just do their own thing. Especially at night. Especially in cities. Especially when drunk.

Does it make sense for there to be a goal of "getting pedestrians to actually press a button"? Sure, that way everyone is following their signals and no one is put in an actionable position (assuming there are no incidents). But in reality, intersections are not friendly for pedestrians outside of timed corridors; most actuated intersections have tiny windows of time to hit those buttons to get the walk sign to come on. Late at night, you come up to cross Broadway, but you arrived two seconds after the walk sign failed to activate. Are you going to wait an entire cycle to cross? No, you just go, cautiously. Are there pedestrians who do this not cautiously at all? Definitely, but there are just as many drivers screaming straight through those intersections under the correct premise that they have the right of way to proceed straight-on (again, short of running someone down intentionally). By replacing the green with a flashing yellow at night, we provide a gentle reminder to drivers that "hey, a lot of people jaywalk around this area at night; don't expect them to cross on a walk sign; drive with caution".

At the end of the day, if this pilot program has received approval from the various regional departments, it's not like California doesn't do their own thing all the time anyway. I'm more than interested to see how this works out.

[jakeroot]

There's a flaw in the first premise. If you watch the video, you can see that the "walk" signal is on while the adjacent flashing yellow is on, which implies the side street seeing red would also be seeing the upraised hand for pedestrians.

No, I assumed that the walk signals were working.  A pedestrian walking up would see the "Don't Walk" signal but also possibly the flashing yellow signal on the main street.  Since they would assume it's on a regular night-time flash, they might assume the walk signal is not functioning (i.e. will not change to "walk") and just treat it as such and go ahead and cross the street.  The average pedestrian is not going to know that the pedestrian signal is supposed to be dark during the regular flash mode.  If they walked up and saw the signal functioning normally, they would probably be more likely to assume they can push the button (if equipped) and wait for the walk signal.

I agree with your interpretation. Most pedestrians, particularly those who don't drive, are not going to be intimately familiar with the operations of intersections in flashing modes (hell, most drivers aren't). The number of drivers that I've seen interpret a solid red arrow lasting slightly too long as meaning "clearly broken", and then turning through a gap, is an indication that people are impatient as shit.

I doubt the flashing yellow setup in LA is going to get people to use caution and slow down.  People treat flashing yellow like there is no signal at all.  When there's a green light, drivers will at least be prepared for the possibility the signal will change.  I think this could potentially lead to more accidents.

But when there is no signal, drivers must yield to pedestrians. This is just as true at intersections with flashing yellow orbs (which are quite common as a way to indicate a pedestrian crosswalk anyways), but very much unlike green lights which give you the right-of-way to proceed straight-on irrespective of pedestrians waiting to cross your road. When you have a green light, you logically don't expect to have to yield to pedestrians, hence LADOT's whole idea here: slightly mislead drivers into thinking these crossings along Broadway might be "yield" situations, to cut down on drivers sailing through them without any caution at all.

I am very skeptical and not a fan of the arrangement.  The pedestrians should wait until it is safe to cross and wait for their WALK signal.

But they don't, so why do we insist that we design an operation that requires them to do so?

[Roadrunner75]

When you have a green light, you logically don't expect to have to yield to pedestrians, hence LADOT's whole idea here: slightly mislead drivers into thinking these crossings along Broadway might be "yield" situations, to cut down on drivers sailing through them without any caution at all.

There's a problem right there - once drivers (at least though who regularly use that street, or the side streets) figure out the trick, they're not going to use caution any more at the flashing yellow because they know it's really a 'green'.  And they just might then assume it works the same at other yellow flashing lights - that pedestrians always have a walk signal and side roads always have a solid red, which will lead to accidents elsewhere.  It's a matter of being consistent - just like the conflict between the alternating reds at the HAWKs and at railroad crossings.  I'm not against innovation.  I just think there are certain fundamentals that you can't mess with.

[mrsman]

I can tell you honestly the way that I drive, is that when I see an intersection with a green light, I go, but I do have in mind that I may have to be prepared for a yellow or red, especially if I also see a FDW and/or pedestrian timer signal.

Flashing yellows at an intersection signify caution, but no specific caution.  But they usually come up in the following scenarios:

* Full time yellow flash to signify that there is an intersection.  (This is usually a flashing yellow cyclops and the side street may be a flashing red cyclops).

* Yellow flash at random times.  The signal is probably broken due to power outage / weather that was recently repaired but the timing has not repaired.  While I do have the right of way, I drive slowly

* Yellow flash at late night hours.  Planned flash operation to improve driving times for cars.  Main streets don't stop at all and you no longer have to worry about signal timing.  Side streets have a flashing red and will cross when they feel it is safe.  While the side streets do not get a ROW, at these times it is easy to find a gap and they will cross.  Yes, I have to expect that possibility, but given that traffic is overall lower, I drive with the same level of caution as at an unsignalized intersection and don't really expect to stop, especially at late nights.

And while in my experience there were few nighttime flash operations in L.A.,** there definitely were such operations in other So Cal cities.  So L.A. drivers should be familiar with nighttime flash and probably treat them the way that I treat them.  But very few expect a flashing yellow to suddenly change to red.




** Where I live now in MD (just outside Washington DC), many intersections go on nighttime flash from 1 am to 5:30 am.  This is not for pedestrian safety, but rather to allow for more efficient car movements.  No stopping on main streets.  Less waiting on side streets (wait for a gap in traffic, but no need to wait at a stale red forever).  In the few areas of this county with nightlife, the signals don't flash.

I have witnessed the change at both 1 am and 5:30 am at the signal closest to my home.  At 1 am the signal on the main street will go from green to yellow to red (briefly) and then
flash yellow.  The side street is all red and then begins to flash when the main signal flashes.  At 5:30 am, the signal just changes from flashing yellow directly to green and the flashing red becomes a solid red.

[Roadrunner75]

But very few expect a flashing yellow to suddenly change to red.

Agree - And even worse at HAWK signals where it's dark and suddenly comes to life.  Another problem with HAWKs - dark signals are supposed to be treated as a "Stop" as if the signal was out, but we created a signal that conflicts with that rule.

I have witnessed the change at both 1 am and 5:30 am at the signal closest to my home.  At 1 am the signal on the main street will go from green to yellow to red (briefly) and then flash yellow.  The side street is all red and then begins to flash when the main signal flashes.  At 5:30 am, the signal just changes from flashing yellow directly to green and the flashing red becomes a solid red.

Does the side street turn to solid red for a few seconds before the main road turns to green?  If someone on the side street approaches right when that changes, they see the flashing red and treat it as a stop and then might pull out right at the change into what has become a green for the main road.  Obviously they had to look for a break in traffic anyway though...