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Author Topic: The Future of Flashing yellow arrows signals  (Read 6392 times)

blue.cable82

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The Future of Flashing yellow arrows signals
« on: August 06, 2017, 07:42:08 PM »

 I know that flashing yellow arrow have been around for a while. I wondering what the future of Flashing yellow arrow signals will be?

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ilpt4u

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Re: The Future of Flashing yellow arrows signals
« Reply #1 on: August 06, 2017, 08:58:11 PM »

How bout just eliminate it and use the 5 Signal Head Tower, which has worked fine for years...

If it ain't broke...Don't fix it

I confess my biases, being an IL driver and the 5 Section Towers are the norm in this state (outside of Peoria, that is, which has gone with the Flashing Yellow Arrow)
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UCFKnights

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Re: The Future of Flashing yellow arrows signals
« Reply #2 on: August 07, 2017, 12:47:59 AM »

How bout just eliminate it and use the 5 Signal Head Tower, which has worked fine for years...

If it ain't broke...Don't fix it

I confess my biases, being an IL driver and the 5 Section Towers are the norm in this state (outside of Peoria, that is, which has gone with the Flashing Yellow Arrow)
The reason for the FYA is the 5 section towers ARE broken and needed fixing. They create yellow trap, which is extremely dangerous, and people frequently forgot they didn't have right of way if they didn't get the green arrow at the beginning of the cycle. FYA has been shown to solve all the problems with the 5 signal head and improve safety... with the added benefit of extra flexibility.
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jeffandnicole

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Re: The Future of Flashing yellow arrows signals
« Reply #3 on: August 07, 2017, 01:11:39 AM »

How bout just eliminate it and use the 5 Signal Head Tower, which has worked fine for years...

If it ain't broke...Don't fix it

I confess my biases, being an IL driver and the 5 Section Towers are the norm in this state (outside of Peoria, that is, which has gone with the Flashing Yellow Arrow)
The reason for the FYA is the 5 section towers ARE broken and needed fixing. They create yellow trap, which is extremely dangerous, and people frequently forgot they didn't have right of way if they didn't get the green arrow at the beginning of the cycle. FYA has been shown to solve all the problems with the 5 signal head and improve safety... with the added benefit of extra flexibility.

Being that many states still don't have flashing yellows, and the states with flashing yellows still have large amounts of intersections without the flashing yellow, the yellow trap you site is made up. People didn't frequently forget anything.

A true yellow trap was when the light for one direction went completely red, however the opposing traffic still had a green. Left turning traffic believed the opposing traffic had a red also, and would complete their turn in front of traffic that still had a green light. Historically, that's how the yellow trap existed.

When you say there's a yellow trap today with a 5 section tower, it's not close to the same thing. Basic rules apply in those instances: traffic turning left on a green ball yields to opposing thru traffic. Its a very basic rule of driving.
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jakeroot

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Re: The Future of Flashing yellow arrows signals
« Reply #4 on: August 07, 2017, 01:22:47 AM »

I don't see a future for the original green-orb PPLT display for dedicated left turn lanes. It doesn't provide as many functions as the FYA, nor does it provide any safety benefits.
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UCFKnights

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Re: The Future of Flashing yellow arrows signals
« Reply #5 on: August 07, 2017, 01:29:18 AM »

How bout just eliminate it and use the 5 Signal Head Tower, which has worked fine for years...

If it ain't broke...Don't fix it

I confess my biases, being an IL driver and the 5 Section Towers are the norm in this state (outside of Peoria, that is, which has gone with the Flashing Yellow Arrow)
The reason for the FYA is the 5 section towers ARE broken and needed fixing. They create yellow trap, which is extremely dangerous, and people frequently forgot they didn't have right of way if they didn't get the green arrow at the beginning of the cycle. FYA has been shown to solve all the problems with the 5 signal head and improve safety... with the added benefit of extra flexibility.

Being that many states still don't have flashing yellows, and the states with flashing yellows still have large amounts of intersections without the flashing yellow, the yellow trap you site is made up. People didn't frequently forget anything.

A true yellow trap was when the light for one direction went completely red, however the opposing traffic still had a green. Left turning traffic believed the opposing traffic had a red also, and would complete their turn in front of traffic that still had a green light. Historically, that's how the yellow trap existed.

When you say there's a yellow trap today with a 5 section tower, it's not close to the same thing. Basic rules apply in those instances: traffic turning left on a green ball yields to opposing thru traffic. Its a very basic rule of driving.
Yellow trap is not solved by time, its solved by the FYA. The way yellow trap has existed has not changed, and its gotten worse with all lights having sensors, adaptively skipping phases of the cycle and changing timings dynamically.

And people do forget (which was unrelated to my yellow trap statement). Thats why many areas post signs to remind people on every single 5 section tower, and even with that, I still see people forget on occasion. Just because they forget and go immediately doesn't mean there is an accident... the opposing traffic will see they forgot and just let them go to avoid the accident.
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jakeroot

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Re: The Future of Flashing yellow arrows signals
« Reply #6 on: August 07, 2017, 01:49:14 AM »

The way yellow trap has existed has not changed, and its gotten worse with all lights having sensors, adaptively skipping phases of the cycle and changing timings dynamically.

That's a fuckin fact. Just the other day, I approached a light to turn right (in a right turn lane). The signal changed from yellow to red for the street that I was turning on to. The signal then realised that I had turned right (and there was no one else approaching), so it never gave my direction a green. The street that I turned on to immediately got a green again (1 second red for them -- yes it visibly confused the drivers).

There's nothing wrong with what happened above. I'm glad that adaptive signals have taken over. They have the potential to seriously improve traffic flow. But they work a hell of a lot better when each movement has its own dedicated signal.



By the way, the diagram with the arrows in the OP is ridiculously confusing. I consider myself a traffic control expert, and I'm lost.
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jeffandnicole

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Re: The Future of Flashing yellow arrows signals
« Reply #7 on: August 07, 2017, 06:09:21 AM »

How bout just eliminate it and use the 5 Signal Head Tower, which has worked fine for years...

If it ain't broke...Don't fix it

I confess my biases, being an IL driver and the 5 Section Towers are the norm in this state (outside of Peoria, that is, which has gone with the Flashing Yellow Arrow)
The reason for the FYA is the 5 section towers ARE broken and needed fixing. They create yellow trap, which is extremely dangerous, and people frequently forgot they didn't have right of way if they didn't get the green arrow at the beginning of the cycle. FYA has been shown to solve all the problems with the 5 signal head and improve safety... with the added benefit of extra flexibility.

Being that many states still don't have flashing yellows, and the states with flashing yellows still have large amounts of intersections without the flashing yellow, the yellow trap you site is made up. People didn't frequently forget anything.

A true yellow trap was when the light for one direction went completely red, however the opposing traffic still had a green. Left turning traffic believed the opposing traffic had a red also, and would complete their turn in front of traffic that still had a green light. Historically, that's how the yellow trap existed.

When you say there's a yellow trap today with a 5 section tower, it's not close to the same thing. Basic rules apply in those instances: traffic turning left on a green ball yields to opposing thru traffic. Its a very basic rule of driving.
Yellow trap is not solved by time, its solved by the FYA. The way yellow trap has existed has not changed, and its gotten worse with all lights having sensors, adaptively skipping phases of the cycle and changing timings dynamically.

And people do forget (which was unrelated to my yellow trap statement). Thats why many areas post signs to remind people on every single 5 section tower, and even with that, I still see people forget on occasion. Just because they forget and go immediately doesn't mean there is an accident... the opposing traffic will see they forgot and just let them go to avoid the accident.

Over 99% of existing traffic lights still operate the way they've operated for decades - without a FYA.  Life goes on fine.  In many states without a FYA, many of their drivers aren't even aware such a function exists.

There's signage at FYA lights instructing people what to do during the flashing yellow, so the signage issue hasn't been eliminated.  And as people have pointed out, FYAs can be used as protected and protected/permissive, so the yellow trap as you define it can still occur.
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kalvado

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Re: The Future of Flashing yellow arrows signals
« Reply #8 on: August 07, 2017, 07:53:36 AM »

What I don't understand is why FYA is not incorporated in existing doghouse layout. For me that doghouse alone is a strong message. and replacing that one with a tower means loosing some communication.
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tradephoric

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Re: The Future of Flashing yellow arrows signals
« Reply #9 on: August 07, 2017, 08:21:58 AM »

What I don't understand is why FYA is not incorporated in existing doghouse layout. For me that doghouse alone is a strong message. and replacing that one with a tower means loosing some communication.

Something like this?

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kalvado

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Re: The Future of Flashing yellow arrows signals
« Reply #10 on: August 07, 2017, 09:06:56 AM »

What I don't understand is why FYA is not incorporated in existing doghouse layout. For me that doghouse alone is a strong message. and replacing that one with a tower means loosing some communication.

Something like this?


No, keeping green arrow in place for protected phase (if any), and repurposing yellow one as FYA/cycle indicator.
I understand that there is some discrepancy about yellow arrow at given moment being a transition to red or FYA, but how big of an issue that is? After all, FYA can also eventually switch to solid red ball...
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Re: The Future of Flashing yellow arrows signals
« Reply #11 on: August 07, 2017, 12:43:43 PM »

And people do forget (which was unrelated to my yellow trap statement). Thats why many areas post signs to remind people on every single 5 section tower, and even with that, I still see people forget on occasion. Just because they forget and go immediately doesn't mean there is an accident... the opposing traffic will see they forgot and just let them go to avoid the accident.
Forget, or just don't care?
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kalvado

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Re: The Future of Flashing yellow arrows signals
« Reply #12 on: August 07, 2017, 12:52:15 PM »

And people do forget (which was unrelated to my yellow trap statement). Thats why many areas post signs to remind people on every single 5 section tower, and even with that, I still see people forget on occasion. Just because they forget and go immediately doesn't mean there is an accident... the opposing traffic will see they forgot and just let them go to avoid the accident.
Forget, or just don't care?
I don't see too many people ignoring traffic lights. Trying to beat - maybe, but not ignore. Stop signs are much more ignorable, and speed limits...
I would expect FYA to inherit low ignore rate of regular traffic light...
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vdeane

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Re: The Future of Flashing yellow arrows signals
« Reply #13 on: August 07, 2017, 01:25:40 PM »

I would think that cutting a turn that forced oncoming traffic to slow down would have more in common with trying (but not necessarily succeeding) to beat the light rather than brazenly running the light.  I suspect many people think "yield" means "I can go if there's any kind of gap or if the car in front of me could go, even if oncoming traffic has to slow down" and not "I need a gap large enough to go without affecting oncoming traffic".
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kalvado

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Re: The Future of Flashing yellow arrows signals
« Reply #14 on: August 07, 2017, 01:42:48 PM »

I would think that cutting a turn that forced oncoming traffic to slow down would have more in common with trying (but not necessarily succeeding) to beat the light rather than brazenly running the light.  I suspect many people think "yield" means "I can go if there's any kind of gap or if the car in front of me could go, even if oncoming traffic has to slow down" and not "I need a gap large enough to go without affecting oncoming traffic".
And sometimes you have no other choice other than to choose minimal gaps. Roundabouts are especially good for that type of training. And as long as a razor blade can go between two bumpers, there should be no complains.
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jakeroot

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Re: The Future of Flashing yellow arrows signals
« Reply #15 on: August 07, 2017, 01:45:31 PM »

What I don't understand is why FYA is not incorporated in existing doghouse layout. For me that doghouse alone is a strong message. and replacing that one with a tower means loosing some communication.

You can't give the left turn a red light while simultaneously giving through traffic a green light. No better than a doghouse/tower.

And as people have pointed out, FYAs can be used as protected and protected/permissive, so the yellow trap as you define it can still occur.

Only if the engineer in-charge fails to setup the signals correctly. Though that's also true for the standard doghouse/tower displays.
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kalvado

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Re: The Future of Flashing yellow arrows signals
« Reply #16 on: August 07, 2017, 02:13:21 PM »

What I don't understand is why FYA is not incorporated in existing doghouse layout. For me that doghouse alone is a strong message. and replacing that one with a tower means loosing some communication.

You can't give the left turn a red light while simultaneously giving through traffic a green light. No better than a doghouse/tower.

And as people have pointed out, FYAs can be used as protected and protected/permissive, so the yellow trap as you define it can still occur.

Only if the engineer in-charge fails to setup the signals correctly. Though that's also true for the standard doghouse/tower displays.

Well, we're (at least I) comparing FYA 4- or 5-light tower with a doghouse. My point is that arranging lights is a tower is as good(or as bad) as putting them in a doghouse, with doghouse having some advantages.
As for prohibiting turns... Here in NYS red arrow means "turn prohibited". So setting up a set of 3 arrows would be an answer. DOes MUTCD allow using yellow arrow within set of 3 as FYA? 
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jakeroot

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Re: The Future of Flashing yellow arrows signals
« Reply #17 on: August 07, 2017, 03:33:12 PM »

What I don't understand is why FYA is not incorporated in existing doghouse layout. For me that doghouse alone is a strong message. and replacing that one with a tower means loosing some communication.

You can't give the left turn a red light while simultaneously giving through traffic a green light. No better than a doghouse/tower.

Well, we're (at least I) comparing FYA 4- or 5-light tower with a doghouse. My point is that arranging lights is a tower is as good(or as bad) as putting them in a doghouse, with doghouse having some advantages.

What are the advantages of a doghouse layout? There are many, many areas of the country that have never used doghouse layouts. Many use the 5-section towers exclusively. Somehow they are getting on just fine (I'd guess).

The only advantage that I can think of, with a doghouse display, is that you could have two sets of solid yellow arrows:

Top: red arrow
Top-left: solid yellow following permissive phase
Top-right: solid yellow following protected phase
Bottom-left: flashing yellow arrow
Bottom-right: solid green arrow

This might help reduce the confusion with the yellow arrow meaning either "permissive phase ending" or "protected phase ending". Alternatively, just lag all turns so that there's only one solid yellow arrow (at the very end following a green arrow to clear any waiting cars). But the idea with the FYA was to allow a mix of lead/lag and TOD phasing, so that misses the point.

As for prohibiting turns... Here in NYS red arrow means "turn prohibited". So setting up a set of 3 arrows would be an answer. DOes MUTCD allow using yellow arrow within set of 3 as FYA? 

Something like this? The FYA can occupy the middle or bottom lens, but increasingly, it occupies the middle.

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paulthemapguy

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Re: The Future of Flashing yellow arrows signals
« Reply #18 on: August 07, 2017, 04:54:33 PM »

The way yellow trap has existed has not changed, and its gotten worse with all lights having sensors, adaptively skipping phases of the cycle and changing timings dynamically.

That's a fuckin fact. Just the other day, I approached a light to turn right (in a right turn lane). The signal changed from yellow to red for the street that I was turning on to. The signal then realised that I had turned right (and there was no one else approaching), so it never gave my direction a green. The street that I turned on to immediately got a green again (1 second red for them -- yes it visibly confused the drivers).

There's nothing wrong with what happened above. I'm glad that adaptive signals have taken over. They have the potential to seriously improve traffic flow. But they work a hell of a lot better when each movement has its own dedicated signal.



By the way, the diagram with the arrows in the OP is ridiculously confusing. I consider myself a traffic control expert, and I'm lost.

This wouldn't happen in Illinois, because here, the change in signal phase begins when a signal switches from green to yellow, not later.  We don't separate the yellow phase from the all-red phase and the next permissive phase of other traffic...it all happens together or not at all.  If the signal commits to all 3 phases at once, the yellow trap is eradicated.
People in the Midwest pull halfway into the intersection to turn left on a protected-permitted left turn, and trying to change that would be impossible since it's so ingrained in our culture.  You can replace the 5-section stacks or doghouses with FYA's, but you'd have to program the phases in the same sequence because of the culture here anyway.  Check out a protected-permitted signal in IL sometime, and you'll see that detector loops won't change anything about a signal's operation once the light switches to yellow--once it decides to turn yellow, nothing's going to stop it from allowing the next permissive phase.
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jakeroot

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Re: The Future of Flashing yellow arrows signals
« Reply #19 on: August 07, 2017, 05:45:20 PM »

The way yellow trap has existed has not changed, and its gotten worse with all lights having sensors, adaptively skipping phases of the cycle and changing timings dynamically.

That's a fuckin fact. Just the other day, I approached a light to turn right (in a right turn lane). The signal changed from yellow to red for the street that I was turning on to. The signal then realised that I had turned right (and there was no one else approaching), so it never gave my direction a green. The street that I turned on to immediately got a green again (1 second red for them -- yes it visibly confused the drivers).

There's nothing wrong with what happened above. I'm glad that adaptive signals have taken over. They have the potential to seriously improve traffic flow. But they work a hell of a lot better when each movement has its own dedicated signal.



By the way, the diagram with the arrows in the OP is ridiculously confusing. I consider myself a traffic control expert, and I'm lost.

This wouldn't happen in Illinois, because here, the change in signal phase begins when a signal switches from green to yellow, not later.  We don't separate the yellow phase from the all-red phase and the next permissive phase of other traffic...it all happens together or not at all.  If the signal commits to all 3 phases at once, the yellow trap is eradicated.

So basically, they aren't adaptive?

The computers at the intersection that I approached saw me, and immediately decided to give my direction a green light. So, the amber phase for the cross-street commenced, but I had already turned on red by the time the cross-street's red light came on. Rather than give my street a green, because it saw no one else approaching, it gave the cross-street a green light again. They're adaptive in the sense that they adapt to real-time information (using cameras). They have their ups and downs. My point originally was that they are sometimes too sensitive. Sometimes so sensitive that I fear they may accidentally create a yellow trap (although only in theory -- I've never actually seen this happen). I'm not even sure why right-turn lanes have sensors, since right on red is legal, and unless there's 500 cars trying to turn right, we don't need a green to complete the maneuver.

People in the Midwest pull halfway into the intersection to turn left on a protected-permitted left turn, and trying to change that would be impossible since it's so ingrained in our culture.  You can replace the 5-section stacks or doghouses with FYA's, but you'd have to program the phases in the same sequence because of the culture here anyway.  Check out a protected-permitted signal in IL sometime, and you'll see that detector loops won't change anything about a signal's operation once the light switches to yellow--once it decides to turn yellow, nothing's going to stop it from allowing the next permissive phase.

What does this have to do with what I wrote? People also wait in the intersection around here. It's not 100% of drivers, but it's more than three-quarters, I'd say.
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Mergingtraffic

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Re: The Future of Flashing yellow arrows signals
« Reply #20 on: August 07, 2017, 06:35:50 PM »

It seems to me that they're trying to reinvent the wheel with a FYA.   Whenever there's an arrow, it means you have the right of way or your right of way is ending.

So, now we throw that logic out the window with the FYA. If you have one you don't have the right of way.  It's blurring the lines too much.

Doghouses work fine.  I'm not a fan of towers as I've been with drivers who, when they see green, even it's a left turn green arrow, they go, not realizing they can't go straight...yet.
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Re: The Future of Flashing yellow arrows signals
« Reply #21 on: August 07, 2017, 06:57:28 PM »

I was somewhat skeptical of the benefits of the FYA.   Then we had several installed nearby.   I now get it and would never go back to the old way.   Local drivers adapted very quickly to the new system.

With a FYA there are more opportunities for permissive left turns than there were with the old system.  When traffic on the opposite side has both a green for straight and a green arrow for left turn my side can now have a flashing yellow for permissive left.   With the doghouse red light that wasn't an option and traffic couldn't turn left during that phase, even if there was no opposing through traffic present.  With the FYA that needless wait is now avoided.



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Re: The Future of Flashing yellow arrows signals
« Reply #22 on: August 07, 2017, 08:37:58 PM »

Doghouses work fine.  I'm not a fan of towers as I've been with drivers who, when they see green, even it's a left turn green arrow, they go, not realizing they can't go straight...yet.

I think your issue is with the shared aspects, not the arrangement of the signal faces. Towers can be, and often are centered between the left through lane and the left turn lane (as I believe they are supposed to be). Doghouses can also be placed directly over the left turn lane. Centered signals are possible either way.
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UCFKnights

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Re: The Future of Flashing yellow arrows signals
« Reply #23 on: August 07, 2017, 08:56:53 PM »

And people do forget (which was unrelated to my yellow trap statement). Thats why many areas post signs to remind people on every single 5 section tower, and even with that, I still see people forget on occasion. Just because they forget and go immediately doesn't mean there is an accident... the opposing traffic will see they forgot and just let them go to avoid the accident.
Forget, or just don't care?
I'd say forget. Generally people seem to forget on lots of smaller side streets, when they get the green ball instead of the green arrow (because they were skipped, usually due to not long enough presence to activate the green arrow, or too few cars in the turning lane for lights programmed that way), and they're used to getting the green arrow first, they accidentally go right when they get the green ball, while the cars in the other direction are also trying to go straight. Its generally a pretty slow movement so its not generally deadly, and the cars are going slow enough that someone notices and hits the brakes to let the car go. It seems to happen a lot on certain intersections around here, that is, until they switched to FYA. I haven't seen it with FYA (infact, it happened a fair amount at a few intersections without a PPLT signal, but they installed FYAs without green arrow at those, and it eliminated the problem on those as well. The people doing it usually give the I'm sorry signal if you honk at them when they realize what they did.

Also, I have never really seen an adaptively programmed signal with doghouses that skips phases for no traffic in all directions that doesn't have the yellow trap issue. The simplest way to check it is stop on the left turn sensor in the green ball direction when no other cars are around (i.e, at night), and wait for your green arrow. If you don't get a red ball in your direction before your green arrow, the intersection is subject to yellow trap, as thats what it just did in the other direction. The signal should either give the left turn arrow in both directions to prevent the yellow trap (preferred to save time), or give the side street a green ball for a few moments before giving you the green arrow. I've never seen the signals programmed "correctly" this way.
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Re: The Future of Flashing yellow arrows signals
« Reply #24 on: August 07, 2017, 10:10:45 PM »

And people do forget (which was unrelated to my yellow trap statement). Thats why many areas post signs to remind people on every single 5 section tower, and even with that, I still see people forget on occasion. Just because they forget and go immediately doesn't mean there is an accident... the opposing traffic will see they forgot and just let them go to avoid the accident.
Forget, or just don't care?
I'd say forget. Generally people seem to forget on lots of smaller side streets, when they get the green ball instead of the green arrow (because they were skipped, usually due to not long enough presence to activate the green arrow, or too few cars in the turning lane for lights programmed that way), and they're used to getting the green arrow first, they accidentally go right when they get the green ball, while the cars in the other direction are also trying to go straight. Its generally a pretty slow movement so its not generally deadly, and the cars are going slow enough that someone notices and hits the brakes to let the car go. It seems to happen a lot on certain intersections around here, that is, until they switched to FYA. I haven't seen it with FYA (infact, it happened a fair amount at a few intersections without a PPLT signal, but they installed FYAs without green arrow at those, and it eliminated the problem on those as well. The people doing it usually give the I'm sorry signal if you honk at them when they realize what they did.

Also, I have never really seen an adaptively programmed signal with doghouses that skips phases for no traffic in all directions that doesn't have the yellow trap issue. The simplest way to check it is stop on the left turn sensor in the green ball direction when no other cars are around (i.e, at night), and wait for your green arrow. If you don't get a red ball in your direction before your green arrow, the intersection is subject to yellow trap, as thats what it just did in the other direction. The signal should either give the left turn arrow in both directions to prevent the yellow trap (preferred to save time), or give the side street a green ball for a few moments before giving you the green arrow. I've never seen the signals programmed "correctly" this way.
WVDOH generally programs signals in the way described that can cause yellow trap like this before. At most intersections, if you wait in a left turn lane with a doghouse signal long enough and there's no cross traffic calling their phase, you will get an arrow. Oncoming traffic has no way to know that your through movement still has a green. I've been stuck in the resulting yellow trap situation before.

I'm not sure if I'd want to force a red to allow the arrow to occur, but I might only allow the arrow to happen if it had been preceded by a phase that served side road traffic. That would eliminate the yellow trap. Of course, FLYA would, too.
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