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

Started by NJRoadfan, June 17, 2010, 10:58:35 AM

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agentsteel53

Quote from: spooky on June 30, 2014, 02:57:16 PM

The FYA for a permissive-only left turn has a red arrow, yellow arrow, flashing yellow arrow. A FYA for a protected/permissive left should be a 4-section head with a red arrow, yellow arrow, flashing yellow arrow, and green arrow.

the ones I've seen have both yellow arrow functionalities in the same physical space.
live from sunny San Diego.

http://shields.aaroads.com

jake@aaroads.com


spooky

Quote from: agentsteel53 on June 30, 2014, 03:03:34 PM
Quote from: spooky on June 30, 2014, 02:57:16 PM

The FYA for a permissive-only left turn has a red arrow, yellow arrow, flashing yellow arrow. A FYA for a protected/permissive left should be a 4-section head with a red arrow, yellow arrow, flashing yellow arrow, and green arrow.

the ones I've seen have both yellow arrow functionalities in the same physical space.

that's a no-no, according to the MUTCD.

agentsteel53

Quote from: spooky on June 30, 2014, 03:06:03 PM


that's a no-no, according to the MUTCD.

why?  I can understand not having the same box light up different colors, because some people are color-blind and use the positioning instead, but I don't think anyone is blind about "flashing" vs "steady".

I may be able to go look in El Cajon today at the ones I see most often - they're on Magnolia southbound, just south of 8. 

now that I think about it, I can't remember what the ones in Nevada were like when I saw them a few weeks ago.
live from sunny San Diego.

http://shields.aaroads.com

jake@aaroads.com

spooky

Quote from: agentsteel53 on June 30, 2014, 03:24:35 PM
Quote from: spooky on June 30, 2014, 03:06:03 PM


that's a no-no, according to the MUTCD.

why?  I can understand not having the same box light up different colors, because some people are color-blind and use the positioning instead, but I don't think anyone is blind about "flashing" vs "steady".

I may be able to go look in El Cajon today at the ones I see most often - they're on Magnolia southbound, just south of 8. 

now that I think about it, I can't remember what the ones in Nevada were like when I saw them a few weeks ago.

but think about the driver's perception of the transition from flashing to steady. The beginning of the clearance phase is much more discernible if it begins in a separate signal face.

maplestar

Quote from: spooky on June 30, 2014, 03:41:20 PM
Quote from: agentsteel53 on June 30, 2014, 03:24:35 PM
why?  I can understand not having the same box light up different colors, because some people are color-blind and use the positioning instead, but I don't think anyone is blind about "flashing" vs "steady".

I may be able to go look in El Cajon today at the ones I see most often - they're on Magnolia southbound, just south of 8. 

now that I think about it, I can't remember what the ones in Nevada were like when I saw them a few weeks ago.

but think about the driver's perception of the transition from flashing to steady. The beginning of the clearance phase is much more discernible if it begins in a separate signal face.

I will admit that a day or two ago, I almost got myself in trouble, because I perceived an FYA to still be flashing, when it wasn't. I was about to make my left turn when it turned red forcing me to brake much harder than I like to.

jakeroot

I was checking out the recently posted photos from Missoula...thought they were strange. Anyways, left the house to go get lunch and.....WTF!? Same setup just installed nearby:




roadfro

Quote from: agentsteel53 on June 30, 2014, 03:24:35 PM
Quote from: spooky on June 30, 2014, 03:06:03 PM
that's a no-no, according to the MUTCD.

why?  I can understand not having the same box light up different colors, because some people are color-blind and use the positioning instead, but I don't think anyone is blind about "flashing" vs "steady".

The rational was to separate the FYA permissive yellow from the clearance interval yellow, to provide the visual cue that the signal is changing and the driver needs to clear the intersection. This same rational explains why the steady green arrow (protected movement) and FYA (permissive movement) can share the bottom signal section with a bi-modal arrow when a 3-section FYA PPLT face is used.  (This is what Oregon apparently seems to like, but many other places only use where height limitations are a factor.)

Quote from: agentsteel
now that I think about it, I can't remember what the ones in Nevada were like when I saw them a few weeks ago.

PPLTs in Nevada are the standard 4-section display, with rare exception (there's one in downtown Reno using the three-section variant described above).
Roadfro - AARoads Pacific Southwest moderator since 2010, Nevada roadgeek since 1983.

tradephoric

Quote from: jake on June 30, 2014, 06:59:57 PM
I was checking out the recently posted photos from Missoula...thought they were strange. Anyways, left the house to go get lunch and.....WTF!? Same setup just installed nearby:





Great video Jake.  The thing that really stood out is at 0:41 in the video where the left turn lane has gone red while the opposing through is presumably still yellow.  That does not look right and could lead to an increase of head-on left turn accidents.  That flat out looks like a dangerous setup.


jakeroot

Quote from: tradephoric on July 01, 2014, 02:28:34 PM
Quote from: jake on June 30, 2014, 06:59:57 PM
I was checking out the recently posted photos from Missoula...thought they were strange. Anyways, left the house to go get lunch and.....WTF!? Same setup just installed nearby:

Great video Jake.  The thing that really stood out is at 0:41 in the video where the left turn lane has gone red while the opposing through is presumably still yellow.  That does not look right and could lead to an increase of head-on left turn accidents.  That flat out looks like a dangerous setup.

Thanks! People started to wonder if I was a bit of a nutter which prevented me from saying that very same thing out-loud.

froggie

The 3-lens permissive-only FYAs also exist in North Carolina.

route56

Quote from: froggie on July 02, 2014, 02:45:30 PM
The 3-lens permissive-only FYAs also exist in North Carolina.

We've got a few of them here in Lawrence as well. So far, I have not seen any permissive-only installations with FYAs outside of Lawrence, although they have become prevalent in the Kansas City metro (mostly 4-aspect signals; however, there are some 3-aspect signals that have a shared FY/Green arrow.)
Peace to you, and... don't drive like my brother.

R.P.K.

roadfro

Quote from: tradephoric on July 01, 2014, 02:28:34 PM
Quote from: jake on June 30, 2014, 06:59:57 PM
I was checking out the recently posted photos from Missoula...thought they were strange. Anyways, left the house to go get lunch and.....WTF!? Same setup just installed nearby:

Great video Jake.  The thing that really stood out is at 0:41 in the video where the left turn lane has gone red while the opposing through is presumably still yellow.  That does not look right and could lead to an increase of head-on left turn accidents.  That flat out looks like a dangerous setup.

That scenario happens here in Reno also, at FYAs or even with lagging protected lefts.

I believe the cause is not with the signal, but with how the yellow change interval is calculated. The ITE formula for a yellow change interval (a widely recognized standard) takes into account 85th percentile speed on the approach -- since left turning speeds are typically much shorter than the adjacent through, a shorter yellow for the left turn is the result. (I believe Synchro, and possibly some other traffic analysis software, assumes a default lower turning speed for this calculation.) I don't think it causes potential for more accidents or is very dangerous (since that amount of time is very short), but I do agree it looks weird.

In Las Vegas, I'm pretty sure the norm is to set the left turn yellow as the same duration as the through yellow, so the entire approach turns red simultaneously.
Roadfro - AARoads Pacific Southwest moderator since 2010, Nevada roadgeek since 1983.

brickbuilder711

A flashing yellow U-Turn has been spotted on SR 37 in Lakeland, FL; and a new FYA installation has been going up on a span wire on SR 60 near W Lake Wales, FL.

thenetwork

CDOT in Western Colorado has converted many "Doghouse Left intersections" recently...Unfortunately, all of these same former doghouse intersections are now Red Arrow Left intersections, which means longer unnecessary waits.

It wouldn't be bad if CDOT would program the lights where the waits at red lights would be minimal (they don't), but there are too many former doghouse intersections (Grand Junction, Montrose, Delta) that would have benefited more with FYAs than protected lefts, especially in areas with low traffic volumes most of the time.

cl94

Still none in New York outside of Rochester, Binghamton, or New York City that I know of. In most cases, I only see them causing trouble. As stated before, we either have fully-protected lefts or permissive lefts without dedicated left turn signals. None of the "flashing red" crud or odd signal phasing. People typically know to yield on green. Protected lefts are usually restricted to multi-lane situations, divided highways, cases where roads intersect at an angle that is very acute, or a turn across 3 or more lanes. In each a permissive left would be unsafe. You never see a dedicated turn signal outside of these situations.
Please note: All posts represent my personal opinions and do not represent those of my employer or any of its partner agencies.

Travel Mapping (updated weekly)

Revive 755

The plans for adding FYAs to Randall Road in Kane County, IL, are up for the August 1 letting.  Link to plan set.

vdeane

Quote from: cl94 on July 10, 2014, 09:22:14 PM
Still none in New York outside of Rochester, Binghamton, or New York City that I know of. In most cases, I only see them causing trouble. As stated before, we either have fully-protected lefts or permissive lefts without dedicated left turn signals. None of the "flashing red" crud or odd signal phasing. People typically know to yield on green. Protected lefts are usually restricted to multi-lane situations, divided highways, cases where roads intersect at an angle that is very acute, or a turn across 3 or more lanes. In each a permissive left would be unsafe. You never see a dedicated turn signal outside of these situations.
There's a couple east of Utica, on the intersections between NY 5S and NY 28.
Please note: All comments here represent my own personal opinion and do not reflect the official position of NYSDOT or its affiliates.

roadman

MassDOT will eventually be phasing in FYAs at appropriate locations, hopefully starting within the next year.  They are presently completing a review of the signal equipment at each protected/permissive location within the state that is under their jurisdiction.  This is so they can determine whether the controllers and malfunction management units (fka "conflict monitors") at each location can accommodate FYA, can be upgraded to accept FYA, or will need to be replaced so the intersection can be converted to FYA.
"And ninety-five is the route you were on.  It was not the speed limit sign."  - Jim Croce (from Speedball Tucker)

"My life has been a tapestry
Of years of roads and highway signs" (with apologies to Carole King and Tom Rush)

cl94

I was in Rochester 3 weeks ago and I drove past the FYA on NY 441 in Brighton. It was inactive. Don't know if it's only running at certain times of the day, but it wasn't during a relatively off-peak time and no signs were present.
Please note: All posts represent my personal opinions and do not represent those of my employer or any of its partner agencies.

Travel Mapping (updated weekly)

vdeane

I know it's active at least some of the time but I'm not sure what the schedule is.
Please note: All comments here represent my own personal opinion and do not reflect the official position of NYSDOT or its affiliates.

Revive 755


cl94

Quote from: Revive 755 on August 19, 2014, 10:26:56 PM
Latest interim approval from FHWA might be of interest:
Interim Approval 17

Cheaper to manufacture. Smaller signal housing and one fewer "lamp" to maintain.
Please note: All posts represent my personal opinions and do not represent those of my employer or any of its partner agencies.

Travel Mapping (updated weekly)

jakeroot

Quote from: cl94 on August 19, 2014, 11:22:05 PM
Quote from: Revive 755 on August 19, 2014, 10:26:56 PM
Latest interim approval from FHWA might be of interest:
Interim Approval 17

Cheaper to manufacture. Smaller signal housing and one fewer "lamp" to maintain.

What exactly was the purpose of the 4-section housing anyways? Just an extra lamp space so people knew that they should be yielding versus preparing to stop?

signalman

Quote from: jake on August 20, 2014, 02:24:09 AM
Quote from: cl94 on August 19, 2014, 11:22:05 PM
Quote from: Revive 755 on August 19, 2014, 10:26:56 PM
Latest interim approval from FHWA might be of interest:
Interim Approval 17

Cheaper to manufacture. Smaller signal housing and one fewer "lamp" to maintain.

What exactly was the purpose of the 4-section housing anyways? Just an extra lamp space so people knew that they should be yielding versus preparing to stop?
Yes.  For the record, I don't like this new proposal.  I don't think a signal should flash and display a steady color in the same signal head.  It just sounds like an invitation for trouble and confusion for some drivers.

roadfro

Quote from: jake on August 20, 2014, 02:24:09 AM
Quote from: cl94 on August 19, 2014, 11:22:05 PM
Quote from: Revive 755 on August 19, 2014, 10:26:56 PM
Latest interim approval from FHWA might be of interest:
Interim Approval 17

Cheaper to manufacture. Smaller signal housing and one fewer "lamp" to maintain.

What exactly was the purpose of the 4-section housing anyways? Just an extra lamp space so people knew that they should be yielding versus preparing to stop?

That was exactly it. It was felt that, in applications where the permissive phase ends with a change to red, the visual "jump" of the yellow arrow between a flashing signal section and a steady signal section would provide that extra cue to drivers that the phase was ending.

Quote from: signalman on August 20, 2014, 03:21:19 AM
For the record, I don't like this new proposal.  I don't think a signal should flash and display a steady color in the same signal head.  It just sounds like an invitation for trouble and confusion for some drivers.

I am in agreement with you, signalman. However, I do see the economic rationale with this decision, as it potentially allows FYA conversion without new signal hardware. But I still don't think this is a good move to combine the two yellow meanings in the same signal section, as it could invite confusion. When you compare to the 3-section bimodal display FYA option (using a green arrow and flashing yellow arrow in the same bottom section), where the yellow change interval is still separate from the protected/permitted section--that option makes more intuitive sense.
Roadfro - AARoads Pacific Southwest moderator since 2010, Nevada roadgeek since 1983.



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