Has the flashing yellow left turn signal made it to your state?

[mrsman]

Very interesting question.  As far as flashing yellow arrows are concerned I think it's strongly depends upon the signal timing.  Generally I am not a big fan of using fya for emergency vehicle preemption or railroad crossing preemption since it is very easy to create yellow trap even with using FYA.  That being said one can certainly envision where in a lead lag situation fya signal is necessary to prevent yellow trap on the leading side but not necessary on the lagging side.  So I don't believe simply replacing only one of the dog houses with fya would lead to yellow trap.

As far as the layout of the 134 westbound ramps on Alameda, if I remember correctly the original configuration did not allow the left turn on to the first set of ramps.  As this is an area of heavy employment with lots of movie studios nearby, the city probably realized that do a lot of traffic coming from the East heading to the westbound freeway and to even out some of the load they'll allow traffic to use both ramps.  One thing to keep in mind is that since the left turn it's just before the major Street, Hollywood way,   there is a lot of time available to make a permissive left turn when traffic at the upcoming light is red.  Also I believe there may have been plans to get rid of the other on-ramp but those in that have never been carried out.  it's an interesting question and hopefully some of the regulars on Pacific Southwest who are familiar with a lot of LA area history can opine further.

Nexus 5X

[roadman]

Generally I am not a big fan of using fya for emergency vehicle preemption or railroad crossing preemption

I can't envision a situation where you would want to use a FYA for either emergency vehicle or railroad crossing preemption.

[fwydriver405]

Generally I am not a big fan of using fya for emergency vehicle preemption or railroad crossing preemption

I can't envision a situation where you would want to use a FYA for either emergency vehicle or railroad crossing preemption.

Some of the signals in New Hampshire and Maine near me cause a yellow trap on approaches that can turn permissively by wrongly terminating the green ball for all other approaches while holding a protected green for the approaching emergency vehicle. Despite this, a lot of the new intersections I've seen give an all red clearance before assigning ROW to the emergency vehicle.

There is an intersection in Concord (near the NH State Prison for Men) with FYA that is programmed correctly for a preemption, but in Downtown Concord at Main and Pleasant, despite having 3-section permissive only FYA's in 3 out of the 4 approaches, there is a risk of yellow trap as the opposing left turn goes from FYA -> SYA -> SRA while the direction of the emergency vehicle remain's green (thru) + FYA (left) when ROW is requested. Witnessed that when I saw Concord police responding to an call on Main.

[SignBridge]

Emergency vehicle pre-emption has its pros and cons. Sometimes it can cause as many traffic problems as it solves. In Nassau County, NY on Long Island, the County DPW does not have any pre-empters on county roads and has supposedly refused to install them. Don't know if the reasoning is financial or something else. But NYSDOT Region-10 on Long Island does have them at signals on state roads.

[Revive 755]

Very interesting question.  As far as flashing yellow arrows are concerned I think it's strongly depends upon the signal timing.  Generally I am not a big fan of using fya for emergency vehicle preemption or railroad crossing preemption since it is very easy to create yellow trap even with using FYA.

I can't envision a situation where you would want to use a FYA for either emergency vehicle or railroad crossing preemption.

If it is properly set up, a FYA can be used for preemption without a regular yellow trap.  Perceived yellow trap, maybe.

For a four-leg intersection with a railroad crossing on one leg, FYA heads can be used to prohibit the left turn across the railroad without having to use either a blank out sign (which could be confusing when it conflicts with a 'left turn yield on circular green sign') or having to go to a protected-only left. 

[UCFKnights]

Emergency vehicle pre-emption has its pros and cons. Sometimes it can cause as many traffic problems as it solves. In Nassau County, NY on Long Island, the County DPW does not have any pre-empters on county roads and has supposedly refused to install them. Don't know if the reasoning is financial or something else. But NYSDOT Region-10 on Long Island does have them at signals on state roads.

I know in my area they used to install emergency pre-empters everywhere, they generally worked really poorly. When they upgraded to FYA and implemented a new "connected signal" software, they removed the pre-emption from the programming of the lights and stopped installing it on new signals, so its no longer used anymore. From my anecdotal experience on the roads, it definetely hasn't negatively impacted emergency vehicle response. Its hard to tell if there's significant improvement... it definitely gets traffic operations back to normal a whole lot quicker after the emergency vehicle goes by with the devices disabled. They seem to always deploy 2 emergency vehicles from the fire departments whenver there is a call, but like 2 minutes apart (presumably the first people ready to leave the station go in the first vehicle, then the rest in the second vehicle, and one vehicle is more equipped for medical, the other more for rescue/fire/etc). The old pre-emption process basically made the intersection almost all red for a good 3-4 minutes as a result of that. That usually means it would take like 2 full cycles to restore normal traffic during midday traffic (roughly 10 minutes) and serious delays for rush hour commutes. Without the pre-emption traffic restores to normal probably within 2-3 minutes.

[mrsman]

Emergency vehicle pre-emption has its pros and cons. Sometimes it can cause as many traffic problems as it solves. In Nassau County, NY on Long Island, the County DPW does not have any pre-empters on county roads and has supposedly refused to install them. Don't know if the reasoning is financial or something else. But NYSDOT Region-10 on Long Island does have them at signals on state roads.

I know in my area they used to install emergency pre-empters everywhere, they generally worked really poorly. When they upgraded to FYA and implemented a new "connected signal" software, they removed the pre-emption from the programming of the lights and stopped installing it on new signals, so its no longer used anymore. From my anecdotal experience on the roads, it definetely hasn't negatively impacted emergency vehicle response. Its hard to tell if there's significant improvement... it definitely gets traffic operations back to normal a whole lot quicker after the emergency vehicle goes by with the devices disabled. They seem to always deploy 2 emergency vehicles from the fire departments whenver there is a call, but like 2 minutes apart (presumably the first people ready to leave the station go in the first vehicle, then the rest in the second vehicle, and one vehicle is more equipped for medical, the other more for rescue/fire/etc). The old pre-emption process basically made the intersection almost all red for a good 3-4 minutes as a result of that. That usually means it would take like 2 full cycles to restore normal traffic during midday traffic (roughly 10 minutes) and serious delays for rush hour commutes. Without the pre-emption traffic restores to normal probably within 2-3 minutes.

IMO, emergency vehicles already have sirens to get others to stop for them.  To the extent that there are vehicles already in the intersection (like waiting for a gap to make a left), those vehicles will be the first to clear the intersection when the emergency vehicle passes and then it should revert to normal traffic pattern.  I don't think anything is gained by putting in a preemption sequence in the signals.

Or maybe I have yet to see it done in an appropriate fashion.

[roadman]

Emergency vehicle pre-emption has its pros and cons. Sometimes it can cause as many traffic problems as it solves. In Nassau County, NY on Long Island, the County DPW does not have any pre-empters on county roads and has supposedly refused to install them. Don't know if the reasoning is financial or something else. But NYSDOT Region-10 on Long Island does have them at signals on state roads.

I know in my area they used to install emergency pre-empters everywhere, they generally worked really poorly. When they upgraded to FYA and implemented a new "connected signal" software, they removed the pre-emption from the programming of the lights and stopped installing it on new signals, so its no longer used anymore. From my anecdotal experience on the roads, it definetely hasn't negatively impacted emergency vehicle response. Its hard to tell if there's significant improvement... it definitely gets traffic operations back to normal a whole lot quicker after the emergency vehicle goes by with the devices disabled. They seem to always deploy 2 emergency vehicles from the fire departments whenver there is a call, but like 2 minutes apart (presumably the first people ready to leave the station go in the first vehicle, then the rest in the second vehicle, and one vehicle is more equipped for medical, the other more for rescue/fire/etc). The old pre-emption process basically made the intersection almost all red for a good 3-4 minutes as a result of that. That usually means it would take like 2 full cycles to restore normal traffic during midday traffic (roughly 10 minutes) and serious delays for rush hour commutes. Without the pre-emption traffic restores to normal probably within 2-3 minutes.

IMO, emergency vehicles already have sirens to get others to stop for them.  To the extent that there are vehicles already in the intersection (like waiting for a gap to make a left), those vehicles will be the first to clear the intersection when the emergency vehicle passes and then it should revert to normal traffic pattern.  I don't think anything is gained by putting in a preemption sequence in the signals.

Or maybe I have yet to see it done in an appropriate fashion.

Many communities have restrictions on siren use by emergency vehicles, even when they're responding to a call.  This is to appease people who've decided that all noise is pure evil and must be totally eradicated.  Also, consider the situation where the emergency vehicle has to make a left turn, but there isn't a protected left turn bay.  Preemption insures that the opposing traffic will stop, rather than relying on the assumption that the driver will automatically recognize the emergency vehicle in time to stop.

[roadman]

Very interesting question.  As far as flashing yellow arrows are concerned I think it's strongly depends upon the signal timing.  Generally I am not a big fan of using fya for emergency vehicle preemption or railroad crossing preemption since it is very easy to create yellow trap even with using FYA.

I can't envision a situation where you would want to use a FYA for either emergency vehicle or railroad crossing preemption.

If it is properly set up, a FYA can be used for preemption without a regular yellow trap.  Perceived yellow trap, maybe.

For a four-leg intersection with a railroad crossing on one leg, FYA heads can be used to prohibit the left turn across the railroad without having to use either a blank out sign (which could be confusing when it conflicts with a 'left turn yield on circular green sign') or having to go to a protected-only left. 

IMO, a left turn across a railroad crossing should always be a protected turn.

[jakeroot]

For a four-leg intersection with a railroad crossing on one leg, FYA heads can be used to prohibit the left turn across the railroad without having to use either a blank out sign (which could be confusing when it conflicts with a 'left turn yield on circular green sign') or having to go to a protected-only left. 

IMO, a left turn across a railroad crossing should always be a protected turn.

Why? Just use a blank-out sign; this is standard in WA (no rule here about protected turns across railways). There's not enough trains along virtually any at-grade railway in the US to justify 24/7 protection, especially when the booms will keep cars from turning into trains for those that do arrive.

For the record, even with FYAs, you'd need to use blankout signs. Bringing up a red arrow in the middle of phase is not permitted for either left or right turns no matter what kind of turn signal it is. All movements would have to go red to not use blankout signs. Better solution, as seen in my link, is to keep through traffic moving, and activate a blankout sign.

[RestrictOnTheHanger]

For a four-leg intersection with a railroad crossing on one leg, FYA heads can be used to prohibit the left turn across the railroad without having to use either a blank out sign (which could be confusing when it conflicts with a 'left turn yield on circular green sign') or having to go to a protected-only left. 

IMO, a left turn across a railroad crossing should always be a protected turn.

Why? Just use a blank-out sign; this is standard in WA (no rule here about protected turns across railways). There's not enough trains along virtually any at-grade railway in the US to justify 24/7 protection, especially when the booms will keep cars from turning into trains for those that do arrive.

For the record, even with FYAs, you'd need to use blankout signs. Bringing up a red arrow in the middle of phase is not permitted for either left or right turns no matter what kind of turn signal it is. All movements would have to go red to not use blankout signs. Better solution, as seen in my link, is to keep through traffic moving, and activate a blankout sign.

In a lot of cases, there is a track clearance interval anyway, so an all red phase is feasible.

[jakeroot]

For a four-leg intersection with a railroad crossing on one leg, FYA heads can be used to prohibit the left turn across the railroad without having to use either a blank out sign (which could be confusing when it conflicts with a 'left turn yield on circular green sign') or having to go to a protected-only left. 

IMO, a left turn across a railroad crossing should always be a protected turn.

Why? Just use a blank-out sign; this is standard in WA (no rule here about protected turns across railways). There's not enough trains along virtually any at-grade railway in the US to justify 24/7 protection, especially when the booms will keep cars from turning into trains for those that do arrive.

For the record, even with FYAs, you'd need to use blankout signs. Bringing up a red arrow in the middle of phase is not permitted for either left or right turns no matter what kind of turn signal it is. All movements would have to go red to not use blankout signs. Better solution, as seen in my link, is to keep through traffic moving, and activate a blankout sign.

In a lot of cases, there is a track clearance interval anyway, so an all red phase is feasible.

I think it depends on the alignment of the intersection. If cars are allowed to stop on both sides of the tracks, I usually see that approach get a green light for about 10 seconds to clear any cars that might be stopped, before the parallel roadway gets a green for the remaining duration of the train. If vehicles wait on the far side of the tracks, the parallel road will keep its green, and a blankout "NO LEFT/RIGHT TURN" sign activates.

[Chuttlely]

FYAs have taken some areas of Texas by storm and others have none.  Austin has installed them at new intersections and is adding them slowly to other intersections.  TxDOT has 25 districts, and some have installed more than others.  For example, Austin District has a good amount whereas Amarillo has virtually none.

[fwydriver405]

In Dover NH, there's this intersection that has yellow trap (in the opposing direction) due to the lead-lag phasing, but has a left-facing FYA for the left-turn slip lane from Central to Washington Ave. If the 4-section PPLT signals were replaced with FYA's, would it be confusing to have another FYA with a diagonal upward-facing left arrow for turns from Central Ave onto Henry Law Ave, assuming the signals aren't louvred and no "LEFT TURN SIGNAL" signs or similar are needed?

[roadfro]

In Dover NH, there's this intersection that has yellow trap (in the opposing direction) due to the lead-lag phasing, but has a left-facing FYA for the left-turn slip lane from Central to Washington Ave. If the 4-section PPLT signals were replaced with FYA's, would it be confusing to have another FYA with a diagonal upward-facing left arrow for turns from Central Ave onto Henry Law Ave, assuming the signals aren't louvred and no "LEFT TURN SIGNAL" signs or similar are needed?

It wouldn't seem too confusing to me. The diagonal FYA would need to be positioned or angled just right to not be confused with the left FYA for the slip lane (I make the assumption that these can be operated independently). Some upstream lane use signage could help.

[jakeroot]

In Dover NH, there's this intersection that has yellow trap (in the opposing direction) due to the lead-lag phasing, but has a left-facing FYA for the left-turn slip lane from Central to Washington Ave. If the 4-section PPLT signals were replaced with FYA's, would it be confusing to have another FYA with a diagonal upward-facing left arrow for turns from Central Ave onto Henry Law Ave, assuming the signals aren't louvred and no "LEFT TURN SIGNAL" signs or similar are needed?

It wouldn't seem too confusing to me. The diagonal FYA would need to be positioned or angled just right to not be confused with the left FYA for the slip lane (I make the assumption that these can be operated independently). Some upstream lane use signage could help.

If they were perhaps a bit more visible, something like this in Vancouver could help identify which signal is for which road.

[Amtrakprod]

Very interesting question.  As far as flashing yellow arrows are concerned I think it's strongly depends upon the signal timing.  Generally I am not a big fan of using fya for emergency vehicle preemption or railroad crossing preemption since it is very easy to create yellow trap even with using FYA.  That being said one can certainly envision where in a lead lag situation fya signal is necessary to prevent yellow trap on the leading side but not necessary on the lagging side.  So I don't believe simply replacing only one of the dog houses with fya would lead to yellow trap.

As far as the layout of the 134 westbound ramps on Alameda, if I remember correctly the original configuration did not allow the left turn on to the first set of ramps.  As this is an area of heavy employment with lots of movie studios nearby, the city probably realized that do a lot of traffic coming from the East heading to the westbound freeway and to even out some of the load they'll allow traffic to use both ramps.  One thing to keep in mind is that since the left turn it's just before the major Street, Hollywood way,   there is a lot of time available to make a permissive left turn when traffic at the upcoming light is red.  Also I believe there may have been plans to get rid of the other on-ramp but those in that have never been carried out.  it's an interesting question and hopefully some of the regulars on Pacific Southwest who are familiar with a lot of LA area history can opine further.

Nexus 5X

Why? Just have the flashing yellow go on while the tracks clear, such as this instance in North Carolina: https://youtu.be/Z9GjmBBIeOk?t=159

[Amtrakprod]

Generally I am not a big fan of using fya for emergency vehicle preemption or railroad crossing preemption

I can't envision a situation where you would want to use a FYA for either emergency vehicle or railroad crossing preemption.

Some of the signals in New Hampshire and Maine near me cause a yellow trap on approaches that can turn permissively by wrongly terminating the green ball for all other approaches while holding a protected green for the approaching emergency vehicle. Despite this, a lot of the new intersections I've seen give an all red clearance before assigning ROW to the emergency vehicle.

There is an intersection in Concord (near the NH State Prison for Men) with FYA that is programmed correctly for a preemption, but in Downtown Concord at Main and Pleasant, despite having 3-section permissive only FYA's in 3 out of the 4 approaches, there is a risk of yellow trap as the opposing left turn goes from FYA -> SYA -> SRA while the direction of the emergency vehicle remain's green (thru) + FYA (left) when ROW is requested. Witnessed that when I saw Concord police responding to an call on Main.

There is an intersection near me that gives the fire trucks direction a green ball (even though it could give a left arrow as well as it's a doghouse signal) and the opposing direction gets a red, it's still yellow trap. https://www.google.com/maps/@42.4179436,-71.1651269,3a,75y,108.39h,89.79t/data=!3m6!1e1!3m4!1si6LK8BfsP3P3BIruEmKMzQ!2e0!7i16384!8i8192

[fwydriver405]

Earlier today, I was looking around the California MUTCD 2014 Edition and saw this line on page 856 regarding yellow trap:

W25-1/2 sign shall not be used in California.

Does that mean that yellow trap sequences in California are either prohibited or just hidden/unsigned, and do other states that have state amendments have this rule as well? I've wondered why California would prohibit displaying these signs at intersections with a yellow trap, especially in cases like this (rail preemption). Except for the occasional intersection that has rail or fire preempt, I'm guessing that this sequence is rare as they have a lot of protected-only lefts over in CA...

[jakeroot]

I've wondered why California would prohibit displaying these signs at intersections with a yellow trap, especially in cases like this (rail preemption). Except for the occasional intersection that has rail or fire preempt, I'm guessing that this sequence is rare as they have a lot of protected-only lefts over in CA...

Ideally, yellow trap should be avoided even with railroad preemption. I don't understand, at your linked examples, why there is a recurring issue with yellow trap. Clearly someone has set something up wrong.

I suspect the signs "shall not be used" because yellow trap (as it may say somewhere else in California's manual) "shall not be used" either. Ergo, no need for the sign. This section operates under the assumption that the sign will not be used because the situation warranting the sign would not arise in California. There clearly was no thought given to the possibility of an engineer not programming an intersection correctly. Although I think an engineer, upon discovering the yellow trap, would instead fix the intersection programming, instead of simply putting up some signs that drivers may or may not notice.

In Clark County, WA, a whole bunch of "extended green" signs were installed about ten years ago, although they've all been removed. Apart from these, I can't readily recall any W25-1/2 signs in Washington State either. I suspect the sign is allowed (I'm thinking there is one somewhere in King County, but I don't recall where), but the situation is not permitted according to WSDOT's signal guidance manual (or whatever it's called); basically, lead/lag green arrows are not permitted with protected-permitted operation.

[Amtrakprod]

Earlier today, I was looking around the California MUTCD 2014 Edition and saw this line on page 856 regarding yellow trap:

W25-1/2 sign shall not be used in California.

Does that mean that yellow trap sequences in California are either prohibited or just hidden/unsigned, and do other states that have state amendments have this rule as well? I've wondered why California would prohibit displaying these signs at intersections with a yellow trap, especially in cases like this (rail preemption). Except for the occasional intersection that has rail or fire preempt, I'm guessing that this sequence is rare as they have a lot of protected-only lefts over in CA...

California seems to have a bunch of yellow trap issues. In MA, at grade crossings typically a RYGL will be installed in the opposite directions and a lead lag would be used. As seen here , but some older ones exist: like, here, and, here. Sadly a few new lights still are set up in a flawed way: https://www.google.com/maps/@42.5579933,-70.8806437,3a,37.2y,134.74h,94.18t/data=!3m6!1e1!3m4!1sn4NHV9b6LnYXQgXBVmV0MA!2e0!7i16384!8i8192

[Declan127]

Woodhaven Blvd, NY

[jakeroot]

Woodhaven Blvd, NY

Could you possibly expand a little on this? Such as which intersections?

Thanks

[RestrictOnTheHanger]

Woodhaven Blvd, NY

Could you possibly expand a little on this? Such as which intersections?

Thanks

I believe Woodhaven Blvd has some right turn FYAs as opposed to left turn ones.

Here is a rare right turn 8-8-12 FYA that was recently installed

https://maps.app.goo.gl/8RQrEFYJ5qPpJ3Li7

[jakeroot]

Here is a rare right turn 8-8-12 FYA that was recently installed

https://maps.app.goo.gl/8RQrEFYJ5qPpJ3Li7

Just when I thought I had seen it all.