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Author Topic: The Future of Flashing yellow arrows signals  (Read 8145 times)

kalvado

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Re: The Future of Flashing yellow arrows signals
« Reply #50 on: August 09, 2017, 08:33:48 AM »


Its important to remember that any flashing yellow signal ultimately means proceed using the rules of the road as if there was no signal here (but with caution). A yellow flashing ball would seem to have priority for those approaching it over the green arrow (that they can't see), as its not the normal rule of the road.
Quite interesting interpretation, makes a quite a bit of sense. Does not address traffic on perpendicular road, though.
Is that spelled out in MUTCD, or that is your own wording? 
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jeffandnicole

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Re: The Future of Flashing yellow arrows signals
« Reply #51 on: August 09, 2017, 08:56:06 AM »

Maybe its just my learned driving habits, but a Permissive Left Turn phase should coincide with your "Thru" traffic having a Green Signal for the straight movement

There is no way it is safer for Left Turners than it is for Straight/Through traffic in this situation (if the Opposing direction has Protected Green Left Turn combined with Green for Straight/Through traffic.) At worst, it should be "Flashing Yellow" for Left Turning AND Straight/Through Traffic

It is pretty easy to dream up a scenario where Oncoming/Opposing Traffic has a Green Ball with Green Left Arrow, and there is traffic going straight but not turning. Why shouldn't the "Other" direction's straight movement have a "Permissive" Straight movement with a Flashing Yellow Ball, if Left Turning movement can have a "Permissive" Left movement with a Flashing Yellow Arrow

I'm looking for consistency here
Its important to remember that any flashing yellow signal ultimately means proceed using the rules of the road as if there was no signal here (but with caution). A yellow flashing ball would seem to have priority for those approaching it over the green arrow (that they can't see), as its not the normal rule of the road.

Since when and in what universe does a yellow traffic signal have any priority over a green traffic signal???  A good traffic light setup doesn't allow you to see what the other directions have anyway.  You're not supposed to approach a signal and decide what you want to do based on the colors of the other directions.

For what it's worth, here's the 'normal' law: http://www.leg.state.fl.us/Statutes/index.cfm?App_mode=Display_Statute&Search_String=&URL=0300-0399/0316/Sections/0316.076.html

I'm not sure what you mean by normal laws and not normal laws.  I guess traffic light colors fall under not normal laws to you, and red, yellow and green don't mean anything?

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kalvado

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Re: The Future of Flashing yellow arrows signals
« Reply #52 on: August 09, 2017, 09:07:51 AM »

Maybe its just my learned driving habits, but a Permissive Left Turn phase should coincide with your "Thru" traffic having a Green Signal for the straight movement

There is no way it is safer for Left Turners than it is for Straight/Through traffic in this situation (if the Opposing direction has Protected Green Left Turn combined with Green for Straight/Through traffic.) At worst, it should be "Flashing Yellow" for Left Turning AND Straight/Through Traffic

It is pretty easy to dream up a scenario where Oncoming/Opposing Traffic has a Green Ball with Green Left Arrow, and there is traffic going straight but not turning. Why shouldn't the "Other" direction's straight movement have a "Permissive" Straight movement with a Flashing Yellow Ball, if Left Turning movement can have a "Permissive" Left movement with a Flashing Yellow Arrow

I'm looking for consistency here
Its important to remember that any flashing yellow signal ultimately means proceed using the rules of the road as if there was no signal here (but with caution). A yellow flashing ball would seem to have priority for those approaching it over the green arrow (that they can't see), as its not the normal rule of the road.

Since when and in what universe does a yellow traffic signal have any priority over a green traffic signal???  A good traffic light setup doesn't allow you to see what the other directions have anyway.  You're not supposed to approach a signal and decide what you want to do based on the colors of the other directions.

For what it's worth, here's the 'normal' law: http://www.leg.state.fl.us/Statutes/index.cfm?App_mode=Display_Statute&Search_String=&URL=0300-0399/0316/Sections/0316.076.html

I'm not sure what you mean by normal laws and not normal laws.  I guess traffic light colors fall under not normal laws to you, and red, yellow and green don't mean anything?

Looks like issue is with meaning of flashing yellow.
Solid green for northbound +FYA for southbound is a meaningful combination, southbound left turn yields, northbound straight has right of way.
Flashing yellow ball for northbound + green arrow for southbound is NOT a meaningful combination since it grants right of way to two conflicting moves.

It may be important to send the message to each and every driver that flashing yellow has somewhat different meaning for an arrow and a ball....
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jeffandnicole

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Re: The Future of Flashing yellow arrows signals
« Reply #53 on: August 09, 2017, 09:32:53 AM »

Yellow doesn't grant right of way.  Yellow is caution.

If the yellow is steady, it means that the light is about to turn red, and it cautions you to slow down if you have enough time to stop.

If the yellow is a flashing yellow arrow, it means about the same as a yield sign: You can make the left turn if safe to do so, but if not you have to stop and wait.  A flashing yellow arrow has never been construed to allow someone to fly thru an intersection without care of other traffic.
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Re: The Future of Flashing yellow arrows signals
« Reply #54 on: August 09, 2017, 09:49:11 AM »

Maybe its just my learned driving habits, but a Permissive Left Turn phase should coincide with your "Thru" traffic having a Green Signal for the straight movement

There is no way it is safer for Left Turners than it is for Straight/Through traffic in this situation (if the Opposing direction has Protected Green Left Turn combined with Green for Straight/Through traffic.) At worst, it should be "Flashing Yellow" for Left Turning AND Straight/Through Traffic

It is pretty easy to dream up a scenario where Oncoming/Opposing Traffic has a Green Ball with Green Left Arrow, and there is traffic going straight but not turning. Why shouldn't the "Other" direction's straight movement have a "Permissive" Straight movement with a Flashing Yellow Ball, if Left Turning movement can have a "Permissive" Left movement with a Flashing Yellow Arrow

I'm looking for consistency here
Its important to remember that any flashing yellow signal ultimately means proceed using the rules of the road as if there was no signal here (but with caution). A yellow flashing ball would seem to have priority for those approaching it over the green arrow (that they can't see), as its not the normal rule of the road.

Since when and in what universe does a yellow traffic signal have any priority over a green traffic signal???  A good traffic light setup doesn't allow you to see what the other directions have anyway.  You're not supposed to approach a signal and decide what you want to do based on the colors of the other directions.

For what it's worth, here's the 'normal' law: http://www.leg.state.fl.us/Statutes/index.cfm?App_mode=Display_Statute&Search_String=&URL=0300-0399/0316/Sections/0316.076.html

I'm not sure what you mean by normal laws and not normal laws.  I guess traffic light colors fall under not normal laws to you, and red, yellow and green don't mean anything?
Again, I don't know what your talking about. It seems your simply not reading my posts and then calling me crazy. The post I replied to asked about a flashing yellow ball and why can't we have that opposing a green arrow. I replied explaining why that wouldn't make sense. The perception of the driver of the flashing yellow ball is that nobody else is going to have a green signal to go in front of them. Someone else who has a flashing yellow signal and is turning in front of them would be expected to yield to those going straight, just as if there was no signal. Traffic from the side streets is expected to have a flashing red signal, and be the lowest priority of them all. We don't have a flashing yellow ball in one direction and have the perpendicular street having a green ball for this reason. The flashing yellow would assume they have priority over the green ball as they DON'T KNOW the other direction has a green ball, and those facing the green ball would assume they have priority over the yellow ball, but even that is unclear.

The Florida statute you linked to is completely consistent with what I said. The only modifier from the normal traffic rules of a flashing yellow light is "with caution".

Quote from: kalvado
Quite interesting interpretation, makes a quite a bit of sense. Does not address traffic on perpendicular road, though.
Is that spelled out in MUTCD, or that is your own wording?
A perpendicular road shouldn't be presented with any signal that isn't colored red (whether flashing or solid) when there is any green or yellow (whether solid or flashing) for the original road.
And yes, thats my own wording.

Quote from: kalvado
Looks like issue is with meaning of flashing yellow.
Solid green for northbound +FYA for southbound is a meaningful combination, southbound left turn yields, northbound straight has right of way.
Flashing yellow ball for northbound + green arrow for southbound is NOT a meaningful combination since it grants right of way to two conflicting moves.
Yes,that combination would be equivalent to have a flashing yellow ball for northbound, southbound, eastbound, AND westbound at the same time. Because it appears to be a controlled intersection, but its entirely uncontrolled. Only part I would disagree with is the word "grants" because the yellow signal technically does not do that, the ONLY meaning of it is "use caution"

Quote
It may be important to send the message to each and every driver that flashing yellow has somewhat different meaning for an arrow and a ball....
It doesn't though. Here's the "consistent" way to think of the signals:
Solid red: Stop and wait for signal to change (unless a specific law grants proceeding on red after stop, which varies by state)
Flashing red: Treat as a stop sign
Solid yellow: The previous indication is ending and a new one will soon appear, that likely requires you to stop.
Flashing yellow: Use caution. Follow all laws and rules on proceeding through the intersection as you don't have any traffic control device changing any meaning for you.
Green: Proceed after yielding to anything already in the intersection. You have the "protected" right of way for entering the intersection.

The arrow modified the signal to become more specific then the ball, so if an arrow indication faces in your direction, you should follow that over any ball. Just as if there is a bus signal sign and you are operating a bus in a bus lane, you should follow that over any other signal.

Its extremely consistent. Infact, the only real inconsistency is on the solid GREEN BALL, which really has the meaning of a straight green arrow, as right turns have to yield to pedestrians/bikes and left turns have to yield to both pedestrians/bikes and oncoming traffic.
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Re: The Future of Flashing yellow arrows signals
« Reply #55 on: August 09, 2017, 10:07:00 AM »

Yellow doesn't grant right of way.  Yellow is caution.

If the yellow is steady, it means that the light is about to turn red, and it cautions you to slow down if you have enough time to stop.

If the yellow is a flashing yellow arrow, it means about the same as a yield sign: You can make the left turn if safe to do so, but if not you have to stop and wait.  A flashing yellow arrow has never been construed to allow someone to fly thru an intersection without care of other traffic.

A flashing yellow does grant right of way if going straight, as the cross street always has a flashing red.
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jeffandnicole

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Re: The Future of Flashing yellow arrows signals
« Reply #56 on: August 09, 2017, 10:07:45 AM »

A perpendicular road shouldn't be presented with any signal that isn't colored red (whether flashing or solid) when there is any green or yellow (whether solid or flashing) for the original road.
And yes, thats my own wording.

A green left arrow on one road also permits for a green right arrow on a perpendicular road.  This is a very normal signal function.
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kalvado

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Re: The Future of Flashing yellow arrows signals
« Reply #57 on: August 09, 2017, 10:09:09 AM »


It doesn't though. Here's the "consistent" way to think of the signals:
Solid red: Stop and wait for signal to change (unless a specific law grants proceeding on red after stop, which varies by state)
Flashing red: Treat as a stop sign
Solid yellow: The previous indication is ending and a new one will soon appear, that likely requires you to stop.
Flashing yellow: Use caution. Follow all laws and rules on proceeding through the intersection as you don't have any traffic control device changing any meaning for you.
Green: Proceed after yielding to anything already in the intersection. You have the "protected" right of way for entering the intersection.

Yellow doesn't grant right of way.  Yellow is caution.

If the yellow is steady, it means that the light is about to turn red, and it cautions you to slow down if you have enough time to stop.

If the yellow is a flashing yellow arrow, it means about the same as a yield sign: You can make the left turn if safe to do so, but if not you have to stop and wait.  A flashing yellow arrow has never been construed to allow someone to fly thru an intersection without care of other traffic.
Well, maybe I am stupid - but what does "use caution" means in terms of operating vehicle? Speed, acceleration? I thought driver is always supposed to take reasonable precautions in order to avoid accidents, even if it would be someone's else fault, right?
The way someone explained flashing yellow ball to me many moons ago - and yes, that is not the letter, but the spirit of the law:
"flashing yellow for you means flashing red = stop for perpendicular direction. You go they wait". Which is, pretty much, right of way. Same as with stop signs on perpendicular road - where I can see the shape of the sign, and get same message.

Now what I don't like is that flashing colors have no permanent meaning. (Solid red also has some discrepancies, BTW).
Flashing red means a stop - except for flashing red at a rail crossing, where it means almost the same as red ball.  Then flashing yellow means I may go and have my priority - except when this is an arrow....
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roadman

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Re: The Future of Flashing yellow arrows signals
« Reply #58 on: August 09, 2017, 10:22:37 AM »

As I understand it, the whole reason the flashing yellow arrow (FYA) came into existence is because apparently drivers have become so dumb that they no longer understand that, when taking a left turn on a green ball, it is your responsibility to YIELD to oncoming traffic.

So, and meaning no disrespect to the legions of people who developed, studied, and evaluated the FYA BEFORE having it adopted as a MUTCD standard, instead of conducting campaigns to re-educate drivers about the meaning of a green ball and how you are supposed to take left turns when facing one, we have developed an entirely new signal indication that is not at all intuitive, and has required state and local agencies to conduct campaigns to educate drivers about the meaning of the FYA and how you are supposed to take a left turn when facing one.

FWIW, about a month ago I encountered my first FYA as a driver - it's by the building with my cardiologist's office.  Apart from the fact that the FYA is first activated when opposing traffic still has a red ball (and does for about 30 seconds afterwards), I was so fixated on looking for a gap, I almost failed to notice the signal change to a green arrow - which also tells me that perhaps FYA is useless at this location, at least may not be an appropriate indication during certain times of day.  I'll also note that, this location was not a retrofit, but an entirely new signal and controller installation.
« Last Edit: August 09, 2017, 10:58:44 AM by roadman »
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kalvado

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Re: The Future of Flashing yellow arrows signals
« Reply #59 on: August 09, 2017, 10:31:07 AM »

As I see it, the whole reason the flashing yellow came into existence is because apparently drivers have become so dumb that they no longer understand that, when taking a left turn on a green ball, it is your responsibility to YIELD to oncoming traffic.

So, and meaning no disrespect to the legions of people who developed, studied, and evaluated the FYA BEFORE having it adopted as a MUTCD standard, instead of conducting campaigns to re-educate drivers about the meaning of a green ball and how you are supposed to take left turns when facing one, we have developed an entirely new signal indication that is not at all intuitive, and has required state and local agencies to conduct campaigns to educate drivers about the meaning of the FYA and how you are supposed to take a left turn when facing one.

FWIW, about a month ago I encountered my first FYA as a driver - it's by the building with my cardiologist's office.  Apart from the fact that the FYA is first activated when opposing traffic still has a red ball (and does for about 30 seconds afterwards), I was so fixated on looking for a gap, I almost failed to notice the signal change to a green arrow - which also tells me that perhaps FYA is useless at this location, at least during certain times of day.  I'll also note that, this location was not a retrofit, but an entirely new signal and controller installation.

My personal justification for FYA is that it may be displayed without green ball, decoupling 2 moves. That is, when oncoming traffic has green left turn arrow, and during transitions from solid green ball to solid red ball+green arrow. Nothing more, nothing less.
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jeffandnicole

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Re: The Future of Flashing yellow arrows signals
« Reply #60 on: August 09, 2017, 10:39:47 AM »

As I understand it, the whole reason the flashing yellow arrow (FYA) came into existence is because apparently drivers have become so dumb that they no longer understand that, when taking a left turn on a green ball, it is your responsibility to YIELD to oncoming traffic.

So, and meaning no disrespect to the legions of people who developed, studied, and evaluated the FYA BEFORE having it adopted as a MUTCD standard, instead of conducting campaigns to re-educate drivers about the meaning of a green ball and how you are supposed to take left turns when facing one, we have developed an entirely new signal indication that is not at all intuitive, and has required state and local agencies to conduct campaigns to educate drivers about the meaning of the FYA and how you are supposed to take a left turn when facing one.

FWIW, about a month ago I encountered my first FYA as a driver - it's by the building with my cardiologist's office.  Apart from the fact that the FYA is first activated when opposing traffic still has a red ball (and does for about 30 seconds afterwards), I was so fixated on looking for a gap, I almost failed to notice the signal change to a green arrow - which also tells me that perhaps FYA is useless at this location, at least during certain times of day.  I'll also note that, this location was not a retrofit, but an entirely new signal and controller installation.

If you only encountered this one time, and during that one time there wasn't a gap, how does that translate to it being useless (even during certain times of day).

Traffic engineers look at how an intersection performs 24 hours a day.  If they made their decision based on a single trip thru an intersection, signal times would be horrendously poor.


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roadman

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Re: The Future of Flashing yellow arrows signals
« Reply #61 on: August 09, 2017, 11:04:24 AM »

As I understand it, the whole reason the flashing yellow arrow (FYA) came into existence is because apparently drivers have become so dumb that they no longer understand that, when taking a left turn on a green ball, it is your responsibility to YIELD to oncoming traffic.

So, and meaning no disrespect to the legions of people who developed, studied, and evaluated the FYA BEFORE having it adopted as a MUTCD standard, instead of conducting campaigns to re-educate drivers about the meaning of a green ball and how you are supposed to take left turns when facing one, we have developed an entirely new signal indication that is not at all intuitive, and has required state and local agencies to conduct campaigns to educate drivers about the meaning of the FYA and how you are supposed to take a left turn when facing one.

FWIW, about a month ago I encountered my first FYA as a driver - it's by the building with my cardiologist's office.  Apart from the fact that the FYA is first activated when opposing traffic still has a red ball (and does for about 30 seconds afterwards), I was so fixated on looking for a gap, I almost failed to notice the signal change to a green arrow - which also tells me that perhaps FYA is useless at this location, at least during certain times of day.  I'll also note that, this location was not a retrofit, but an entirely new signal and controller installation.
If you only encountered this one time, and during that one time there wasn't a gap, how does that translate to it being useless (even during certain times of day).
Traffic engineers look at how an intersection performs 24 hours a day.  If they made their decision based on a single trip thru an intersection, signal times would be horrendously poor.

Yes, I understand how traffic signal timings are developed.  I get your point, and have modified my post.  However, after my appointment (about 11:30 in the morning), I went down to the intersection and observed the signal operation for several cycles.  During all of the FYA cycles, the opposing traffic did not provide any gaps for left turners.  That to me indicates a problem with using FYA in this situation during certain times of day.
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Re: The Future of Flashing yellow arrows signals
« Reply #62 on: August 09, 2017, 06:47:38 PM »

If the yellow is a flashing yellow arrow, it means about the same as a yield sign: You can make the left turn if safe to do so, but if not you have to stop and wait.  A flashing yellow arrow has never been construed to allow someone to fly thru an intersection without care of other traffic.

I seem to recall reading that there was once a split-phased intersection in Indiana that had night flashing and used a flashing yellow arrow one direction while the other legs had flashing red indications.
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Re: The Future of Flashing yellow arrows signals
« Reply #63 on: August 09, 2017, 08:45:19 PM »

During all of the FYA cycles, the opposing traffic did not provide any gaps for left turners.  That to me indicates a problem with using FYA in this situation during certain times of day.

If I'm understanding correctly, you're describing something that is more related to the split time of the protected phase rather than the method of display (FYA vs permissive-green-ball).

Your story reminds me of another bonus of FYA (other than the big one pointed out by Kalvado): permissive turns don't have to be allowed when the same approach's through movement goes green.  I can think of two situations this is helpful.  1. You can prohibit permissive turns by time of day.  I'm not sure that I typically agree with the idea, but I've heard signal technicians implement this based upon specific volume patterns.  Say a school is releasing and you know the opposing through is so high there will be no gaps for lefts, so you don't want them to make a risky move.  2. You can prohibit permissive turns during cycles with conflicting pedestrian movements.  I don't know enough about signal programming to be certain, but I believe the green ball on the five section head always displays when the through movement does.

Partial Hijack: I seem to remember Utah using FYA for some right turns (I remember an example of a DDI with pedestrian crossing)...do we know if that practice has become more widespread?  Or have you ever seen FYA for a DDI left-turn?
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Re: The Future of Flashing yellow arrows signals
« Reply #64 on: August 09, 2017, 09:27:18 PM »

Your story reminds me of another bonus of FYA (other than the big one pointed out by Kalvado): permissive turns don't have to be allowed when the same approach's through movement goes green.  I can think of two situations this is helpful.  1. You can prohibit permissive turns by time of day.  I'm not sure that I typically agree with the idea, but I've heard signal technicians implement this based upon specific volume patterns.  Say a school is releasing and you know the opposing through is so high there will be no gaps for lefts, so you don't want them to make a risky move.  2. You can prohibit permissive turns during cycles with conflicting pedestrian movements.  I don't know enough about signal programming to be certain, but I believe the green ball on the five section head always displays when the through movement does.

Not to shit all over your post, but I did mention these things on the last page:

There are FYAs in nearly all jurisdictions within 400 miles of me , yet not a single one (AFAIK) operates FYAs in this manner, probably because it doesn't make any sense. Some do have odd quirks:

- protected-only based on time of day (although increasingly normal)
- longer all-red phases between the protected and permissive phase (though some have none, such as many left turns in Seattle)
- red while pedestrian has walk sign

At least where I am, both things you mentioned are very common. Lynnwood and Federal Way, WA both block out the permissive phase during peak hours. Bellevue and Puyallup block out the permissive phase when the pedestrian walk sign is on. Both are certainly controversial in their own right. I'm not sure I have an opinion on either just yet.

Partial Hijack: I seem to remember Utah using FYA for some right turns (I remember an example of a DDI with pedestrian crossing)

I-15 NB slip lane (exit 284) towards Timpanogos Hwy.
« Last Edit: August 10, 2017, 02:44:58 AM by jakeroot »
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Re: The Future of Flashing yellow arrows signals
« Reply #65 on: August 09, 2017, 11:28:12 PM »

Partial Hijack: I seem to remember Utah using FYA for some right turns (I remember an example of a DDI with pedestrian crossing)...do we know if that practice has become more widespread?  Or have you ever seen FYA for a DDI left-turn?

I-15 NB slip lane (exit 284) towards Timpanogos Hwy.

Jakeroot is right, and that's still the only one I know of. I believe all DDI left turns are protected only here in UT, but some might offer a turn on red after a full stop (pretty sure not, but it could be). I have definitely never seen a FYA on a DDI left.

If a separate signal is used for right turns, it is almost always a doghouse, which is tied to the left turn signal for cross traffic from the right (which is also given a No U-turn sign). There is one intersection in St. George which uses a 5-section vertical signal for the right turn. Right turn signals are generally only used where there is high right-turn volume.
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Re: The Future of Flashing yellow arrows signals
« Reply #66 on: August 10, 2017, 05:02:54 AM »

Not to shit all over your post, but I did mention these things on the last page:

Oops, my bad!  The irony is that I was answering yet another "what's wrong with the old way of permissive lefts? " which has been asked approximately a billion times.  I made the same error they do by posting without reading the thread.

The reason I ask about the DDI left is that some areas have laws that allow left on red between two one-way streets.  That applies at a DDI, but most drivers don't know the rule.  Perhaps a FYA would be a way to allow this movement rather than a "left on red after stop" sign.
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Re: The Future of Flashing yellow arrows signals
« Reply #67 on: August 10, 2017, 09:45:56 AM »

My personal justification for FYA is that it may be displayed without green ball, decoupling 2 moves. That is, when oncoming traffic has green left turn arrow, and during transitions from solid green ball to solid red ball+green arrow. Nothing more, nothing less.

I just wanted to say that I like this feature of FYA's too, and I agree with you.  FYA's also separate straight movements and turning movements better than doghouses/5-section stacks, if road agencies wish to do that.  FYA's have the most versatility--but if you're in a simple situation, and you want to maximize green time for all phases, you're just going to operate the signal in the same way doghouses have been running for decades.  If you have railroads, crosswalks, or odd configurations, FYA's give you a lot more options.  In basic situations, though, the added versatility of FYA's doesn't really help you unless you overthink an intersection's operation.
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jakeroot

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Re: The Future of Flashing yellow arrows signals
« Reply #68 on: August 10, 2017, 08:46:53 PM »

Not to shit all over your post, but I did mention these things on the last page:

Oops, my bad!  The irony is that I was answering yet another "what's wrong with the old way of permissive lefts? " which has been asked approximately a billion times.  I made the same error they do by posting without reading the thread.

No worries mate! The entire FYA discussion (this one plus about a billion others) really just rehash the same concerns/explanations over and over again. This thread is completely redundant, but it is what it is.

The reason I ask about the DDI left is that some areas have laws that allow left on red between two one-way streets.  That applies at a DDI, but most drivers don't know the rule.  Perhaps a FYA would be a way to allow this movement rather than a "left on red after stop" sign.

Washington would be one of those states. We also allow left turns onto one-ways from two-ways. Not like that applies here, but drivers are very used to left on red around here. Once WSDOT finishes their first DDI in Lacey, I will let you know how often I see people turn on red.

A left-facing FYA would work well. Depends on how many lanes, though. One would be totally acceptable. Two would be doable. Three might be overkill. Four would be...I'm not sure if there is such a thing: four lanes yielding at once?  :-D I love the sound of it, though!
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Re: The Future of Flashing yellow arrows signals
« Reply #69 on: August 10, 2017, 10:55:05 PM »

The reason I ask about the DDI left is that some areas have laws that allow left on red between two one-way streets.  That applies at a DDI, but most drivers don't know the rule.  Perhaps a FYA would be a way to allow this movement rather than a "left on red after stop" sign.

Utah does have this law (though I don't know of any intersection where this applies!)

The reason it doesn't apply here is that every DDI in Utah has dual left turns, which by state MUTCD requires a protected only movement.
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Re: The Future of Flashing yellow arrows signals
« Reply #70 on: August 10, 2017, 11:19:46 PM »

Not to shit all over your post, but I did mention these things on the last page:

Oops, my bad!  The irony is that I was answering yet another "what's wrong with the old way of permissive lefts? " which has been asked approximately a billion times.  I made the same error they do by posting without reading the thread.

No worries mate! The entire FYA discussion (this one plus about a billion others) really just rehash the same concerns/explanations over and over again. This thread is completely redundant, but it is what it is.

People will also always complain about "the new way of doing things", especially when it comes to traffic control. Apparently back when Huntsville, AL swapped from having black letters on white backgrounds for the street blades here back in the 60s to the current white letters on green backgrounds, many of the older residents complained about the change. I have to wonder how they'd react to seeing the current mixed-case street blades that are being put up!
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Re: The Future of Flashing yellow arrows signals
« Reply #71 on: August 11, 2017, 07:35:30 AM »

People will also always complain about "the new way of doing things", especially when it comes to traffic control. Apparently back when Huntsville, AL swapped from having black letters on white backgrounds for the street blades here back in the 60s to the current white letters on green backgrounds, many of the older residents complained about the change. I have to wonder how they'd react to seeing the current mixed-case street blades that are being put up!
On one hand, that is definitely true. On the other hand, one of big features of US traffic control is that you don't really need to know anything to understand meaning of signs, if you can read very basic English you are good.
Compare that with European standard - which is pictogram oriented, either because there are many languages or because literacy was not a certain thing back when standard was adopted.
Imagine you fly overseas, rent a car (struggle with stickshift, but that is another story), drive out and face this sign:
Or this one:
Good thing they are fairly standard across few countries.
Well, if you did your homework and looked up the rules - it is not a big deal, but....

I don't expect driving laws to be way different across state lines, and I don't really read driver manuals of states I head to. Heck, many people don't know laws of their home state. And certainly I expect minimal difference in signage. Mixed-case white on green clearview is not that different from black on white all-caps highway gothic.  But, like with euoropean signs, there is no way to guess the meaning of FYA. You know it or you don't. And that put it in a different class compared to font color issues.
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Re: The Future of Flashing yellow arrows signals
« Reply #72 on: August 11, 2017, 11:49:07 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.

The doghouse layout can't give left turns a red indication while giving through traffic any other indication.
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Re: The Future of Flashing yellow arrows signals
« Reply #73 on: August 11, 2017, 11:54:36 AM »

The correct programming of a lagging left is to go straight from FYA to a green arrow. If the FYA is going to solid yellow and red before going to the solid green, the signal is programmed wrong. If the signal is programmed correctly, the perceived yellow trap should not occur.

An example of a perceived yellow trap can be seen at 0:39 in this video.  Drivers in the left turn lane who see the adjacent signal heads change to yellow automatically assume the opposing through direction is changing to yellow at the same time.  Before the FYA came into existence, this assumption was almost always correct (because if the opposing thru wasn't changing to yellow simultaneously, it would lead to a yellow trap) .  But now drivers have to realize that the opposing thru may still have a green light when the adjacent thru changes to yellow. 




That's not a yellow trap. Which you know, because you said it's a 'perceived' yellow trap.

The intersection probably would've been better off as a roundabout anyway.

Even then, it's a situation that seems to only be a problem with folks who don't keep their skills current and old people making faulty assumptions.  And not even one that anybody would necessarily make if they're coming from places where one-signal-per-lane is typical.
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Re: The Future of Flashing yellow arrows signals
« Reply #74 on: August 11, 2017, 12:03:06 PM »

^^
Trade, unless you intend to provide some hard evidence that this perceived yellow trap is an actual issue, your point is moot.

The TRB contains literature that discusses the "perceived" yellow trap at FYA:

Quote
Methods for Operation and Detection of the Flashing Yellow Arrow Display:  The Flashing Yellow Arrow (FYA) display is a form of protected-permitted left-turn phasing (PPLT) approved in 2006 by the National Committee on Uniform Traffic Control Devices and is anticipated for inclusion in the next release of the MUTCD. The FYA display eliminates the yellow trap, allows lead-lag phasing with PPLT, and allows time of day selection of protected-only or permitted-only phasing. This paper describes operational and efficiency benefits of the Flashing Yellow Arrow display and how they are achieved by selection of phasing, timing elements, and modified detection methods. In addition, the paper will describe some lessons learned that will be valuable for other engineers who are contemplating or just starting to use the FYA. The question then becomes how the traffic engineer should utilize the power and flexibility of the FYA display and when to exercise restraint. The real power of the FYA becomes available when the engineer starts to break away from “leading lefts only” phasing typically required by traditional PPLT. This paper will discuss different phasing options with the FYA and the pluses and minuses of each in terms of what existing problems they might solve or mitigate. Along with this will be a discussion of detection strategies from simple to complex that can greatly improve the efficiency of the FYA. Finally, there will be a description of a “perceived” yellow trap that can occur in some circumstances with the FYA and how to recognize when it may be a problem.

https://trid.trb.org/view.aspx?id=921218

Beyond that there are agencies that prefer leading lefts over lagging lefts at FYA.  They cite the "perceived yellow trap" issue in their reasoning.  Here’s a snippet from a webinar by the Oregon Transportation Research and Education Consortium about whether or not the FYA solves the yellow trap:

Quote
Q: What degree does the FYA solve the “yellow trap” problem. And does Washington County lead the protected interval at FYA or lead/lag to benefit coordination?

A: The FYA completely solves the yellow trap problem, because now the left turn lane has its own display.  There is still the potential of the “perceived yellow trap” which is when the driver in the left lane sees the adjacent through go solid yellow and thinks that the FYA is also ending.  It is called perceived, because the driver should focus on their own lane’s signal control. Washington County prefers to lead the protected interval at FYA so if the protected left isn’t needed then it can be skipped.  In a coordinated system we will lead or lag whichever benefits the coordination. (SS)

You can still skip a protected left turn at a lagging FYA but it sounds like Washington County chooses not to do that.  They don't want to introduce the perceived yellow trap, so presumably they tie the lagging left turns together to run simultaneously.  Jake, don't you live near Washington County, Oregon?  You tell me how the lagging left installations run there and if any perceived yellow traps exist.

Washington County skips the protected left phase if nobody's waiting behind the line, so you only get the yellow trap if you're the kind of weirdo who stops in the intersection, which isn't legal to do there in the first place anyway.  Or if you're on a bicycle on a poorly tuned induction loop (rare since MSTIPS 2 in the early 1990s, Washington County's usually very good at tuning their induction loops to pick up a bicycle); non-extant if you're waiting behind the line at mast-arm signals since those are all video detection now.

Washington County also gives a FYA when the conflicting crosswalk is on a walk signal, which given weirdly wide streets meeting narrow streets at intersections and local driver behavior, it should be a steady-red during the walk phase, acting as the left turn equivalent of a HAWK.
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