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Traffic signal

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

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SignBridge

Quote from: cockroachking on August 13, 2024, 12:23:17 PM
Quote from: roadfro on August 13, 2024, 11:40:13 AM
Quote from: roadman65 on August 12, 2024, 12:53:34 PMhttps://maps.app.goo.gl/t3ux356j5GeJhYvo6
Typical traffic light in Wyoming at Route junctions.
Interesting that they have all that signage on the mast arms, which can detract from the signal. Conventional wisdom would suggest that signage be placed slightly upstream.

Not to mention that there is only one overhead signal in the first place, which already complicates things in terms of signal visibility.

One overhead and one far-right pole mounted head is reasonable and meets MUTCD standards.


steviep24

Quote from: SignBridge on August 13, 2024, 07:50:25 PM
Quote from: cockroachking on August 13, 2024, 12:23:17 PM
Quote from: roadfro on August 13, 2024, 11:40:13 AM
Quote from: roadman65 on August 12, 2024, 12:53:34 PMhttps://maps.app.goo.gl/t3ux356j5GeJhYvo6
Typical traffic light in Wyoming at Route junctions.
Interesting that they have all that signage on the mast arms, which can detract from the signal. Conventional wisdom would suggest that signage be placed slightly upstream.

Not to mention that there is only one overhead signal in the first place, which already complicates things in terms of signal visibility.

One overhead and one far-right pole mounted head is reasonable and meets MUTCD standards.
Also far left pole mounted as well.

roadman65

https://maps.app.goo.gl/9WBfjMPVHo8UCPjz9
A flashing yellow right arrow at a bike crossing.
Every day is a winding road, you just got to get used to it.

Sheryl Crowe

SignBridge

Quote from: roadman65 on August 14, 2024, 12:30:39 PMhttps://maps.app.goo.gl/9WBfjMPVHo8UCPjz9
A flashing yellow right arrow at a bike crossing.

Hmmm........interesting that a green arrow is not used since the bike lane has a red light in the photo. Guess the City is assuming that many bicyclists won't comply with the signal, so they opted for more caution by drivers.

roadman65

Quote from: SignBridge on August 14, 2024, 08:18:15 PM
Quote from: roadman65 on August 14, 2024, 12:30:39 PMhttps://maps.app.goo.gl/9WBfjMPVHo8UCPjz9
A flashing yellow right arrow at a bike crossing.

Hmmm........interesting that a green arrow is not used since the bike lane has a red light in the photo. Guess the City is assuming that many bicyclists won't comply with the signal, so they opted for more caution by drivers.

Considering that NYC won't use detector loops that the bike lane signal will turn green even if a bicyclist isn't there as clickboxes with set timers along with 50's style mast arms are things NYC stoplights will always have.
Every day is a winding road, you just got to get used to it.

Sheryl Crowe

jakeroot

Quote from: SignBridge on August 14, 2024, 08:18:15 PM
Quote from: roadman65 on August 14, 2024, 12:30:39 PMhttps://maps.app.goo.gl/9WBfjMPVHo8UCPjz9
A flashing yellow right arrow at a bike crossing.

Hmmm........interesting that a green arrow is not used since the bike lane has a red light in the photo. Guess the City is assuming that many bicyclists won't comply with the signal, so they opted for more caution by drivers.

I think the idea is to encourage caution for drivers entering the service road (or whatever it is), as traffic on that road doesn't have a light. Potentially a green arrow may give drivers a false sense of security and encourage lane-sweeping to the right or something.

Basically, I don't think the FYA has anything to do with the bike lane.

SignBridge

Quote from: roadman65 on August 14, 2024, 08:25:53 PM
Quote from: SignBridge on August 14, 2024, 08:18:15 PM
Quote from: roadman65 on August 14, 2024, 12:30:39 PMhttps://maps.app.goo.gl/9WBfjMPVHo8UCPjz9
A flashing yellow right arrow at a bike crossing.

Hmmm........interesting that a green arrow is not used since the bike lane has a red light in the photo. Guess the City is assuming that many bicyclists won't comply with the signal, so they opted for more caution by drivers.

Considering that NYC won't use detector loops that the bike lane signal will turn green even if a bicyclist isn't there as clickboxes with set timers along with 50's style mast arms are things NYC stoplights will always have.

Well detector loops are gradually becoming obsolete anyway. Many jurisdictions are now using mast-arm mounted motion detectors some of which look like cameras. Maybe at some point we will see that in NYC, though I don't know if those 1950's era mast-arms will take the additional weight of those devices.

SignBridge

Quote from: jakeroot on August 15, 2024, 01:07:05 AM
Quote from: SignBridge on August 14, 2024, 08:18:15 PM
Quote from: roadman65 on August 14, 2024, 12:30:39 PMhttps://maps.app.goo.gl/9WBfjMPVHo8UCPjz9
A flashing yellow right arrow at a bike crossing.

 

Hmmm........interesting that a green arrow is not used since the bike lane has a red light in the photo. Guess the City is assuming that many bicyclists won't comply with the signal, so they opted for more caution by drivers.

I think the idea is to encourage caution for drivers entering the service road (or whatever it is), as traffic on that road doesn't have a light. Potentially a green arrow may give drivers a false sense of security and encourage lane-sweeping to the right or something.

Basically, I don't think the FYA has anything to do with the bike lane.

Jakeroot, you might well be right about that.

jeffandnicole

Quote from: SignBridge on August 15, 2024, 04:25:26 PM
Quote from: roadman65 on August 14, 2024, 08:25:53 PM
Quote from: SignBridge on August 14, 2024, 08:18:15 PM
Quote from: roadman65 on August 14, 2024, 12:30:39 PMhttps://maps.app.goo.gl/9WBfjMPVHo8UCPjz9
A flashing yellow right arrow at a bike crossing.

Hmmm........interesting that a green arrow is not used since the bike lane has a red light in the photo. Guess the City is assuming that many bicyclists won't comply with the signal, so they opted for more caution by drivers.

Considering that NYC won't use detector loops that the bike lane signal will turn green even if a bicyclist isn't there as clickboxes with set timers along with 50's style mast arms are things NYC stoplights will always have.

Well detector loops are gradually becoming obsolete anyway. Many jurisdictions are now using mast-arm mounted motion detectors some of which look like cameras. Maybe at some point we will see that in NYC, though I don't know if those 1950's era mast-arms will take the additional weight of those devices.

City grid systems tend to work best in a fixed pattern, since the lights are close and at equal distance intervals.  Side streets off the main thoroughfares will almost always have traffic or pedestrians so the light will cycle anyway.  The further away you get from the heavy city traffic there may be some benefit. 

I still think Detector Loops are best - at least from what I've seen their fail rate is much less than optical viewers, or even radar viewers.  But they don't support cycle detection well - both motorcycles and bicycles - so that's why they are generally being phased out.

PColumbus73

Is it still common for motorcycles to get missed by detector loops?

If so, maybe a pressure plate or body heat sensors would be best used for bike signals?

thenetwork

Quote from: PColumbus73 on August 15, 2024, 04:52:05 PMIs it still common for motorcycles to get missed by detector loops?

If so, maybe a pressure plate or body heat sensors would be best used for bike signals?

I remember rubber(?) pressure plate detectors -- but they were few and far between by the late 70s/early 80s.  I also remember overhead microwave detectors that sorta looked like shower head handles placed before the intersection, and also overhead microwave detectors that looked like lower-hanging street lamps.   

All of these were used in NE OH in various areas, likely in the 50s and 60s and were phased out in the 70s and 80s.

Those modern day motion detectors on signal masts can easily trip unnecessarily during inclement weather (heavier winds, rain and especially when big ass snowflakes are falling).

SignBridge

One advantage for motion detectors over detector loops is that it's a much simpler installation. The roadway doesn't have to be excavated to install the loop and it doesn't have to be re-excavated and re-installed when the road is repaved. That saves money, time and effort.

Rothman

Quote from: jeffandnicole on August 15, 2024, 04:33:39 PM
Quote from: SignBridge on August 15, 2024, 04:25:26 PM
Quote from: roadman65 on August 14, 2024, 08:25:53 PM
Quote from: SignBridge on August 14, 2024, 08:18:15 PM
Quote from: roadman65 on August 14, 2024, 12:30:39 PMhttps://maps.app.goo.gl/9WBfjMPVHo8UCPjz9
A flashing yellow right arrow at a bike crossing.

Hmmm........interesting that a green arrow is not used since the bike lane has a red light in the photo. Guess the City is assuming that many bicyclists won't comply with the signal, so they opted for more caution by drivers.

Considering that NYC won't use detector loops that the bike lane signal will turn green even if a bicyclist isn't there as clickboxes with set timers along with 50's style mast arms are things NYC stoplights will always have.

Well detector loops are gradually becoming obsolete anyway. Many jurisdictions are now using mast-arm mounted motion detectors some of which look like cameras. Maybe at some point we will see that in NYC, though I don't know if those 1950's era mast-arms will take the additional weight of those devices.

City grid systems tend to work best in a fixed pattern, since the lights are close and at equal distance intervals.  Side streets off the main thoroughfares will almost always have traffic or pedestrians so the light will cycle anyway.  The further away you get from the heavy city traffic there may be some benefit. 

I still think Detector Loops are best - at least from what I've seen their fail rate is much less than optical viewers, or even radar viewers.  But they don't support cycle detection well - both motorcycles and bicycles - so that's why they are generally being phased out.

NYSDOT is basically switching over to non-intrusive detection devices, 100%.
Please note: All comments here represent my own personal opinion and do not reflect the official position(s) of NYSDOT.

CJResotko

There are two intersections in Ann Arbor, MI, along Jackson Road with a bit of an odd setup: a regular RYG traffic signal to the left of a left turn doghouse. Don't know whether or not this is MUTCD compliant.

Google Maps links to the intersections:
Jackson and Parkland
Jackson and Auto Mall
*insert something witty here*

Revive 755

^ I don't think that it is MUTCD compliant.  Based on sections 4F.05 and 4F.07 in the 11th Edition the leftmost head would need to at least have a green arrow to be in compliance.

Rothman

Seems even dangerous.
Please note: All comments here represent my own personal opinion and do not reflect the official position(s) of NYSDOT.

CJResotko

Quote from: Revive 755 on August 22, 2024, 11:17:07 PM^ I don't think that it is MUTCD compliant.  Based on sections 4F.05 and 4F.07 in the 11th Edition the leftmost head would need to at least have a green arrow to be in compliance.

Yeah that's what I was thinking too. They should have put a 3-section left turn signal in the leftmost signal's place, like this.
*insert something witty here*

PColumbus73

Seems like it could have been installed in error and no one's gotten around to fix it.

There's a similar error local to me here: https://www.google.com/maps/@33.8121829,-78.7037461,3a,15y,333.73h,96.58t/data=!3m7!1e1!3m5!1stLigyRBez7njNhqD6yEYvw!2e0!5s20141101T000000!7i13312!8i6656?coh=205409&entry=ttu&g_ep=EgoyMDI0MDgyMC4xIKXMDSoASAFQAw%3D%3D

They were apart of a signal replacement, and they never bothered to swap the heads. I'm pretty sure shortly after they were replaced, the arrow on the 4-section was pointed to the right.

mglass87

Here's a signal with a burnt pole and sign blade:

https://maps.app.goo.gl/j8kggn6Ct8hHesaG7

A car crashed into the corner here years ago and burst into flames. Even after all this time, it's still like this.

fwydriver405

Driving to Weymouth yesterday from Stoughton via MA Route 139 East, I came across this signal near the Randolph/Holbrook line that clearly had something wrong with the emergency flash - the Route 139 approaches were alternating flashing circular green and yellow. Only the Route 139 (main street approaches) were doing this - the side streets were correctly flashing red and the pedestrian signals incorrectly flashing Don't Walk.

Is this an issue with the Malfunction Monitoring Unit (MMU) / Conflict Monitor Unit (CMU) or another component failing in the cabinet? Or was the controller confused trying to switch between flash and normal mode? Somehow, railroad preemption cleared the flash mode and forced the signal back into normal mode into preemption (139 EB's left turn onto NB Mill St has yellow trap during this sequence).


Dirt Roads

Quote from: fwydriver405 on September 01, 2024, 12:28:34 PMDriving to Weymouth yesterday from Stoughton via MA Route 139 East, I came across this signal near the Randolph/Holbrook line that clearly had something wrong with the emergency flash - the Route 139 approaches were alternating flashing circular green and yellow. Only the Route 139 (main street approaches) were doing this - the side streets were correctly flashing red and the pedestrian signals incorrectly flashing Don't Walk.

Is this an issue with the Malfunction Monitoring Unit (MMU) / Conflict Monitor Unit (CMU) or another component failing in the cabinet? Or was the controller confused trying to switch between flash and normal mode? Somehow, railroad preemption cleared the flash mode and forced the signal back into normal mode into preemption (139 EB's left turn onto NB Mill St has yellow trap during this sequence).


I've never seen this before.  My first impression is that this is designed to avoid vehicles stopping in crossings during an MMU malfunction flash mode.  At some crossings, it is difficult to program the RR preemption on both the railroad side and the traffic signal side, particularly for train speeds in excess of 60MPH or so.  It was good to see the RR preemption mode still working when the MBTA train came through.

I'm wondering if the alternating green/yellow flash is an experimental MMU malfunction flash mode that is intended to encourage traffic to continue over the crossing, but provide some level of warning that side traffic is in flash mode and might pull into the crossing after yielding.  If so, this green/yellow flash feature would only be needed on the side of the crossing with advance traffic signals (before the crossing), but most traffic signal controllers cannot be programmed in such a manner. 

fwydriver405

Quote from: Dirt Roads on September 01, 2024, 02:00:23 PMI'm wondering if the alternating green/yellow flash is an experimental MMU malfunction flash mode that is intended to encourage traffic to continue over the crossing, but provide some level of warning that side traffic is in flash mode and might pull into the crossing after yielding.  If so, this green/yellow flash feature would only be needed on the side of the crossing with advance traffic signals (before the crossing), but most traffic signal controllers cannot be programmed in such a manner. 

Wouldn't just flashing just circular yellow on the approaches from the railroad crossing or on both approaches (in this particular case, the main street) be less confusing and standardised on almost all controllers, since you said that the green and yellow flash can't be programmed in this manner, even on the newest ATC controllers?

I do remember poking around in the settings on various TS2 Type 1 and ATC controllers back when I was retiming signals around South Portland, but I don't really remember the flash mode parameters unless I look at the documentation for such controllers, which for me were Naztec/Trafficware and McCains.

And by advance traffic signals prior to the crossing, do you mean something like this example?

Ned Weasel

Quote from: plain on March 06, 2023, 05:05:04 PMThey were probably trying to emphasize that particular lane is thru only (based on the 5-section tower to the right of it for right turns).

WA seems to be the state with the most red up arrows still left around.

The MUTCD has banned red and yellow up arrows for a long time (Section 4F.01, Paragraph 09), but new ones are still popping up!

Brand new signal in Kansas City, MO (Main Street and MLK Boulevard): https://maps.app.goo.gl/h3yGGRzqtdmCXzeh8

Recent DDI in Manhattan, KS (KS 18 and KS 113): https://maps.app.goo.gl/iCaj2e63BKY4RSbN6

Also this DDI in New Mexico (I-25 and NM 14): https://maps.app.goo.gl/vgLemGQeSNY7mqAY6

Are exceptions being handed out left and right, and do engineers really believe that sometimes a red up arrow is better than a circular red in certain situations?  Or are some people just forgetting what's in the MUTCD?
"I was raised by a cup of coffee." - Strong Bad imitating Homsar

Disclaimer: Views I express are my own and don't reflect any employer or associated entity.

hotdogPi

It needs to be an arrow to reinforce that turns aren't allowed at all at those locations. I have no idea why the MUTCD prohibits red up arrows.
Clinched

Traveled, plus
US 13, 50
MA 22, 35, 40, 53, 107, 109, 126, 141, 159
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Lowest untraveled: 36

chrisg69911

Interesting install by the NJDOT. Never seen a wood pole with that arm in NJ. The direction I was facing also had one new 12in light (covered) with the original 2 8in lights still functioning.

https://maps.app.goo.gl/UsBRSgJZs5394yMaA





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