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Traffic signal

Started by Tom89t, January 14, 2012, 01:01:45 AM

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mrsman

Quote from: jakeroot on June 30, 2022, 10:41:35 AM
Quote from: Big John on June 30, 2022, 09:19:20 AM
Quote from: jakeroot on June 29, 2022, 11:50:16 PM
Quote from: Lukeisroads on June 29, 2022, 10:58:30 PM
Creative Bakersfield Creative https://www.google.com/maps/@35.3707251,-119.1455968,3a,39y,260.46h,96.44t/data=!3m6!1e1!3m4!1sYOfJaLstlHvA_KvU-KPXSA!2e0!7i16384!8i8192

Additional context and/or thoughts from you would be helpful. I see nothing unusual, apart from the lack of a far-left supplemental turn signal.
MUTCD doesn't like a right turn signal on a far left signal.  For context, need to pan around the intersection to see what is going on and why through traffic is not allowed.

I can see why through traffic isn't permitted, the neighborhood is a RIRO to reduce cut-through traffic. Not too unusual of a setup IMO.

I was under the impression that it was okay to have right or left turn signals position on the opposite corner if that was the only permitted movement, especially in California where post-mounted signals are incredibly common. But I may be mistaken on that.

It seems to be followed generally in other parts of CA as well.  Here are two signals that are right turn only in the LA area, where there is no left side supplemental.

Olive at 5th, Downtown LA:

https://www.google.com/maps/@34.0496962,-118.2526234,3a,15y,228.58h,90.98t/data=!3m6!1e1!3m4!1srqHgg4vQoQe7RNf1w2zT9w!2e0!7i16384!8i8192

Roxbury Dr. at Wilshire, Beverly Hills:

https://www.google.com/maps/@34.0669444,-118.4056667,3a,37.5y,1.85h,89.94t/data=!3m6!1e1!3m4!1sAZhh375AE9Ful-NLvHhYQA!2e0!7i16384!8i8192

CA is very good about side mounted posting.  Side mount posted signals have been around CA since the early days of signaling.  Beginning in the 1950's, CA started using guy wire mast arms for a supplemental overhead signal - but supplemental to the two side mounted.

At some point more recently, I have noticed newer installations treat the left side mount as a signal for left turning vehicles.  For regular intersections, it would be a normal RYG.  For those with protected phases, it would largely match the leftmost overhead signal (i.e. 4 aspect signals for FYA, 5 aspect signals for doghouses or their 5 tower equivalent, 4 aspect signals [RYG-GA] for split-phase and some lagging signals, and RA-YA-GA for fully protected signals.)  But one other aspect of this that I have also noted is that where a left turn is not possible (T-intersections), the left sidemount supplement is completely omitted.  The omission would usually be on newer signals on wide two way streets.  (Older signals largely still have them, as they were once standard, even at T-intersections.)  I guess they figure that nobody is looking at that corner, so no need to put a signal face there.

Here';s a signal in Laguna Niguel with no left side supplement at a T-intersection:

https://www.google.com/maps/@33.5257747,-117.7192674,3a,15y,231.77h,92.74t/data=!3m7!1e1!3m5!1sixSCq35iz-Kd4aI1A8VmMA!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DixSCq35iz-Kd4aI1A8VmMA%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D57.993053%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192

SignBridge

At least in the last photo in Laguna Niguel, there is a near-right corner supplemental head which maintains the usual Calif. standard of 3 heads on the approach where there are two or more lanes. In this case it helps with the slight curve as well.  I'm surprised the above photos in Los Angeles didn't have a near-right signal. 

Amtrakprod

Quote from: roadfro on July 01, 2022, 12:02:41 PM
Quote from: jakeroot on June 30, 2022, 10:41:35 AM
Quote from: Big John on June 30, 2022, 09:19:20 AM
Quote from: jakeroot on June 29, 2022, 11:50:16 PM
Quote from: Lukeisroads on June 29, 2022, 10:58:30 PM
Creative Bakersfield Creative https://www.google.com/maps/@35.3707251,-119.1455968,3a,39y,260.46h,96.44t/data=!3m6!1e1!3m4!1sYOfJaLstlHvA_KvU-KPXSA!2e0!7i16384!8i8192
Additional context and/or thoughts from you would be helpful. I see nothing unusual, apart from the lack of a far-left supplemental turn signal.
MUTCD doesn't like a right turn signal on a far left signal.  For context, need to pan around the intersection to see what is going on and why through traffic is not allowed.
I can see why through traffic isn't permitted, the neighborhood is a RIRO to reduce cut-through traffic. Not too unusual of a setup IMO.

And from that perspective, the use of right red arrows seems particularly egregious if a right turn is the only allowable movement from that side street...why not have a circular red so that it can more readily allow RTOR? (Not sure on the status of right turn on red arrow in California.)
Right turn on red can be really unsafe. Not always the best option, I typically like to restrict it as much as possible.


iPhone
Roadgeek, railfan, and crossing signal fan. From Massachusetts, and in high school. Youtube is my website link. Loves FYAs signals. Interest in Bicycle Infrastructure. Owns one Leotech Pedestrian Signal, and a Safetran Type 1 E bell.

jakeroot

Quote from: mrsman on July 04, 2022, 12:06:47 PM
At some point more recently, I have noticed newer installations treat the left side mount as a signal for left turning vehicles.  For regular intersections, it would be a normal RYG.  For those with protected phases, it would largely match the leftmost overhead signal (i.e. 4 aspect signals for FYA, 5 aspect signals for doghouses or their 5 tower equivalent, 4 aspect signals [RYG-GA] for split-phase and some lagging signals, and RA-YA-GA for fully protected signals.)  But one other aspect of this that I have also noted is that where a left turn is not possible (T-intersections), the left sidemount supplement is completely omitted.  The omission would usually be on newer signals on wide two way streets.  (Older signals largely still have them, as they were once standard, even at T-intersections.)  I guess they figure that nobody is looking at that corner, so no need to put a signal face there.

Here';s a signal in Laguna Niguel with no left side supplement at a T-intersection:

https://www.google.com/maps/@33.5257747,-117.7192674,3a,15y,231.77h,92.74t/data=!3m7!1e1!3m5!1sixSCq35iz-Kd4aI1A8VmMA!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DixSCq35iz-Kd4aI1A8VmMA%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D57.993053%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192

I have actually noticed this change as well. Needless to say, I'm not a big fan.

To my knowledge, there are only two jurisdictions that require a left-side signal no matter what, even at T-intersections or where left turns are not permitted: IDOT District 1 (Chicago), and British Columbia. And with that said, British Columbia is the only place I've been where that rule is completely steadfast: every single intersection has a signal on the left, no matter what. In many cases, the far left corner signal is one of the primary signals, with only a single overhead primary signal, such as here. In cases where the left turn is fully protected, the supplemental signal is instead on the far right corner. At many, many intersections (probably 60 to 70 percent), there is a supplemental signal on both the far left and far right corner; a good chunk of these have only a single overhead signal.

steviep24

#4608
I think they forgot something here.

https://www.google.com/maps/@43.1145112,-77.6225245,3a,75y,111.27h,93.86t/data=!3m6!1e1!3m4!1shxkg6mu9qdlTKvwFl0XxmA!2e0!7i16384!8i8192?hl=en&authuser=0

This signal is new. Normally they would install a FYA with these. Permissive only in this case.

EDIT TO ADD: If the installers didn't intend to install a FYA here then the two signal heads should have been spaced farther apart on the mast arm.

cl94

Quote from: steviep24 on July 13, 2022, 09:21:13 PM
I think they forgot something here.

https://www.google.com/maps/@43.1145112,-77.6225245,3a,75y,111.27h,93.86t/data=!3m6!1e1!3m4!1shxkg6mu9qdlTKvwFl0XxmA!2e0!7i16384!8i8192?hl=en&authuser=0

This signal is new. Normally they would install a FYA with these. Permissive only in this case.

Eh, matches the old configuration. EB didn't have protected/permissive before the rebuild. But the fact that Rochester is installing FYAs on their own roads is fascinating in and of itself, because that signal isn't to state specs.
Please note: All posts represent my personal opinions and do not represent those of my employer or any of its partner agencies.

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SignBridge

cl94, in what way is that new signal not to state specs? It looks correctly designed to me.

cl94

Quote from: SignBridge on July 13, 2022, 10:09:43 PM
cl94, in what way is that new signal not to state specs? It looks correctly designed to me.

For one, yellow signal heads instead of green. Two, none of the signs are on Z-bars.
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)

Amtrakprod

If anyone wondered how MassDOT designed new traffic signal intersections, here's a brand new one! It's got an exclusive walk phase, all direction NTOR, APS buttons, reflective backplates, and bicycle/pedestrian accommodations. Here's an almost 2 minute video of the signal cycling a bit: https://youtu.be/xAYgTkafJUE





iPhone
Roadgeek, railfan, and crossing signal fan. From Massachusetts, and in high school. Youtube is my website link. Loves FYAs signals. Interest in Bicycle Infrastructure. Owns one Leotech Pedestrian Signal, and a Safetran Type 1 E bell.

SignBridge

Quote from: cl94 on July 13, 2022, 10:12:46 PM
Quote from: SignBridge on July 13, 2022, 10:09:43 PM
cl94, in what way is that new signal not to state specs? It looks correctly designed to me.

For one, yellow signal heads instead of green. Two, none of the signs are on Z-bars.

Are either of those roads numbered state routes? If not, I assume the heads can be yellow, not NYS DOT dark green. New York City, Nassau and Suffolk Counties all use yellow heads on their signals. 

cl94

Quote from: SignBridge on July 13, 2022, 10:26:02 PM
Quote from: cl94 on July 13, 2022, 10:12:46 PM
Quote from: SignBridge on July 13, 2022, 10:09:43 PM
cl94, in what way is that new signal not to state specs? It looks correctly designed to me.

For one, yellow signal heads instead of green. Two, none of the signs are on Z-bars.

Are either of those roads numbered state routes? If not, I assume the heads can be yellow, not NYS DOT dark green. New York City, Nassau and Suffolk Counties all use yellow heads on their signals.

NYSDOT projects generally follow NYSDOT specs regardless of who maintains the road. The big exception is NYC, but they get to do their own thing.

This is a numbered road, but it's city-maintained. Given that neither the signal nor the new signs surrounding it follow state specs, I'm willing to assume minimal involvement from the state, other than possibly funding via the MPO.
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)

steviep24

Quote from: cl94 on July 13, 2022, 11:34:52 PM
Quote from: SignBridge on July 13, 2022, 10:26:02 PM
Quote from: cl94 on July 13, 2022, 10:12:46 PM
Quote from: SignBridge on July 13, 2022, 10:09:43 PM
cl94, in what way is that new signal not to state specs? It looks correctly designed to me.

For one, yellow signal heads instead of green. Two, none of the signs are on Z-bars.

Are either of those roads numbered state routes? If not, I assume the heads can be yellow, not NYS DOT dark green. New York City, Nassau and Suffolk Counties all use yellow heads on their signals.

NYSDOT projects generally follow NYSDOT specs regardless of who maintains the road. The big exception is NYC, but they get to do their own thing.

This is a numbered road, but it's city-maintained. Given that neither the signal nor the new signs surrounding it follow state specs, I'm willing to assume minimal involvement from the state, other than possibly funding via the MPO.
That is correct. Although Mt. Hope is NY 15 it is maintained by the city or county. All non NYSDOT signals in Rochester are owned by Monroe County and have mostly the yellow heads.

SignBridge

Back twenty years ago when New York had their own separate MUTCD, it allowed for either green or yellow heads depending on engineering judgment of site conditions though there seemed to be a slight bias toward green in the wording. (Sec. 272-14-a) I don't know if that provision still exists in the current State Supplement.

Lukeisroads


Big John

^^A clear violation of MUTCD mounting height of pedestrian signals.

steviep24


RobbieL2415


SignBridge

Anyone know what railroad that is in the photo? Is it the CSX (former New York Central) Main Line?

betfourteen

https://www.google.com/maps/@28.1874503,-82.3959633,3a,63.3y,150.98h,92.95t/data=!3m6!1e1!3m4!1sNPjRwHKz11VRy6B-UOTzsA!2e0!7i16384!8i8192

I find this intersection interesting....To the left you can see on the mast arm a doghouse signal and a regular signal....to the right....no road, and its been this way for a while too....at least since 2016: https://www.google.com/maps/@28.1874468,-82.3959704,3a,75y,130.49h,92.82t/data=!3m6!1e1!3m4!1suLuRQuqLiTN-yQ8lSjaj_A!2e0!7i13312!8i6656

It's even equipped with a pre-emption device on the mast arm that faces nothing!

PurdueBill

Quote from: betfourteen on July 16, 2022, 09:25:33 PM
https://www.google.com/maps/@28.1874503,-82.3959633,3a,63.3y,150.98h,92.95t/data=!3m6!1e1!3m4!1sNPjRwHKz11VRy6B-UOTzsA!2e0!7i16384!8i8192

I find this intersection interesting....To the left you can see on the mast arm a doghouse signal and a regular signal....to the right....no road, and its been this way for a while too....at least since 2016: https://www.google.com/maps/@28.1874468,-82.3959704,3a,75y,130.49h,92.82t/data=!3m6!1e1!3m4!1suLuRQuqLiTN-yQ8lSjaj_A!2e0!7i13312!8i6656

It's even equipped with a pre-emption device on the mast arm that faces nothing!

Several on the "new" (not that new, but not very old) alignment of US 41 southeast of downtown Chicago have this kind of thing.
https://goo.gl/maps/hNvypm42fDLVsWaE9
It is surprising that they bother using the electricity for signals facing nothing, but it must make sense to someone.

RX78NT-1

I've noticed an odd thing with new signal installations in the Des Moines, IA metro area:

Normally, when a traffic signal changes lights, it's instant. That is, it goes from green -> yellow -> red; the previous light turns off at the same time as the next light turns on.

A few new signal installations here, particularly in the suburbs (several new installs in Ankeny in particular), change differently. The signals change from green -> no light (briefly) -> yellow -> no light (briefly) -> red. The no-light "phase" is a very short interval, but noticeable enough. This also affects the duration of the FYA, as it's on for a shorter period of time before going off again, and it seems "delayed" in turning on whenever it blinks.

Is there an explanation for this? It doesn't happen for all new installations; a recent Iowa DOT install at the IA-44/IA-141 interchange changes lights normally. Is it related to the controller box? It seems to happen with any brand of signal heads, as far as I can tell.



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