On a drive I took this morning in Johnson County, Kansas, I was eastbound on Shawnee Mission Parkway at the I-35 interchange, and the traffic light at the northbound on-ramp went to flashing red before returning to normal a few seconds later. What's more, within the next minute as I waited to turn left, the light went out and then came back on again.
Have any of you seen a traffic light go out as you were approaching it - or, better yet, come up to a non-working signal and seen it come back to life? If so, when and where did it happen? I'm curious to know!
Yep. Not sure of the actual intersections, but have seen a signal conk out on two separate occasions. Signal glitched and then went to flashing in both occasions, both as I was at the stop line in western MA.
Haven't seen one "come back to life."
My experiences are the opposite of Rothman. Seen a few come back to life, haven't seen any go to flash mode (or off completely).
Yikes! I had an incident somewhere here in Central Carolina back maybe 20 years ago or so. I was approaching a stoplight on a rural highway with a green signal at about 45 MPH when the power went off. I was about 100 feet from the intersection and slowing down quickly when the power came back on. Instead of the traffic signal going into a default flash mode, the traffic signal came back up red in my direction and the car on my right pulled out before I could stop. I slammed on the brakes and did an avoidance maneuver to stop partway into the intersection. I had to back up to let traffic to my left proceed when they got the green ball. I couldn't be sure if the car on my right got a green ball immediately, but he sure acted like it.
Quote from: Dirt Roads on May 30, 2022, 02:31:49 PM
Yikes! I had an incident somewhere here in Central Carolina back maybe 20 years ago or so. I was approaching a stoplight on a rural highway with a green signal at about 45 MPH when the power went off. I was about 100 feet from the intersection and slowing down quickly when the power came back on. Instead of the traffic signal going into a default flash mode, the traffic signal came back up red in my direction and the car on my right pulled out before I could stop. I slammed on the brakes and did an avoidance maneuver to stop partway into the intersection. I had to back up to let traffic to my left proceed when they got the green ball. I couldn't be sure if the car on my right got a green ball immediately, but he sure acted like it.
Well, for me, my left-turn light was about to turn green when the signal went out again. I began turning left anyway, and the light came back on again - at which point I was facing a red light and the oncoming traffic had green. I backed up a little to let the oncoming traffic pass, and eventually I got the green left-turn arrow, at which point I finally completed the turn. A crazy sequence, indeed.
Does it count if it's a normal occurrence? Since I work at nights and am up at nights even on my days off I find myself driving around when several nearby intersections switch to a flash mode each evening after 11pm or midnight. I've seen the last full cycle of lights at an intersection before they start flashing for the night, it's a bit strange but I've become used to it. Likewise I've seen the same intersections return to a normal light pattern at 6am.
I once saw one that had been completely out come back on, and it went all flashing red for a while, then all solid red, then back into service -- which seems much more reasonable than what other people on here have mentioned! (I was on foot at the time, so I was able to watch it for a while to see exactly what happened. If I'm remembering correctly, there was actually someone on site working on it at the time, but I certainly would have hoped that they would behave more like this when coming back online after a power outage too!)
What's your experience with traffic lights and power outages? Do they come right back on when power is restored, or do the techs have to restart them?
I went thru one on Rt 13 in Carbondale when it when it was switching from Blinking Red/No Power mode to "Normal" phazed operations (or vice versa): Literally had the Blinking Red and the Solid Green Ball on at the same time, the direction I was traveling. I went thru without stopping. And I still am not sure what the Rules of the Road suggest to do in that scenario
And this is not a light that gives "Blinking Red" during the Overnight hours to Rt 13 traffic. It does go "Blinking Yellow" I think/Blinking Red for cross traffic. Only goes "Blinking Red" with a Power Outage or other failure of the normal operations
Quote from: jay8g on May 30, 2022, 05:56:55 PM
I once saw one that had been completely out come back on, and it went all flashing red for a while, then all solid red, then back into service -- which seems much more reasonable than what other people on here have mentioned! (I was on foot at the time, so I was able to watch it for a while to see exactly what happened. If I'm remembering correctly, there was actually someone on site working on it at the time, but I certainly would have hoped that they would behave more like this when coming back online after a power outage too!)
Signals should always be programmed to start in an all-red mode to prevent some of the problems described upthread. Anyone not paying attention and missing a malfunction, followed by a green light, could cause a lot of trouble.
For the record, I don't believe I have seen a light transition that I can remember.
Quote from: ilpt4u on May 30, 2022, 08:33:59 PM
I went thru one on Rt 13 in Carbondale when it when it was switching from Blinking Red/No Power mode to "Normal" phazed operations (or vice versa): Literally had the Blinking Red and the Solid Green Ball on at the same time, the direction I was traveling. I went thru without stopping. And I still am not sure what the Rules of the Road suggest to do in that scenario
Rules of the Road have nothing to suggest for you...that scenario should never happen. Even if transitioning from a red flash to stop-and-go, red and green should never be displayed simultaneously in the same signal face (5-section PPLT heads notwithstanding).
The transition out of flashing mode should go to steady red and then greens for the major street/movement (assuming it's an all-way red flash) or the flashing yellows go to green for the major movement and the flashing red go to steady red (assuming yellow/red flash). The flashing red with a simultaneous steady green makes me think there was some kind of fault or issue with the signal (or, if that's a regular occurrence, it's older, non-compliant signal programming).
Quote from: roadfro on May 30, 2022, 11:50:19 PM
Quote from: ilpt4u on May 30, 2022, 08:33:59 PM
I went thru one on Rt 13 in Carbondale when it when it was switching from Blinking Red/No Power mode to "Normal" phazed operations (or vice versa): Literally had the Blinking Red and the Solid Green Ball on at the same time, the direction I was traveling. I went thru without stopping. And I still am not sure what the Rules of the Road suggest to do in that scenario
Rules of the Road have nothing to suggest for you...that scenario should never happen. Even if transitioning from a red flash to stop-and-go, red and green should never be displayed simultaneously in the same signal face (5-section PPLT heads notwithstanding).
The transition out of flashing mode should go to steady red and then greens for the major street/movement (assuming it's an all-way red flash) or the flashing yellows go to green for the major movement and the flashing red go to steady red (assuming yellow/red flash). The flashing red with a simultaneous steady green makes me think there was some kind of fault or issue with the signal (or, if that's a regular occurrence, it's older, non-compliant signal programming).
Had never seen it before and have never seen it since at that signal. Something was malfuctioning.
And for more complete information: IL 13 at Striegel Rd on the west side of Carbondale
Take a ride down CT 10 at 10 pm or 6 AM, and you'll see most of the lights either start flashing yellow (after a red cycle at precisely 10:00) or start working.
Quote from: roadfro on May 30, 2022, 11:50:19 PM
Rules of the Road have nothing to suggest for you...that scenario should never happen. Even if transitioning from a red flash to stop-and-go, red and green should never be displayed simultaneously in the same signal face (5-section PPLT heads notwithstanding).
Does that apply to ramp meters too? I know Utah has/had some red/green (no yellow) meters that activated from dark mode by initially turning both the red and green lights on for several seconds. Took me a minute to figure out what was going on the first time I saw it.
Quote from: US 89 on May 31, 2022, 01:40:12 PM
Quote from: roadfro on May 30, 2022, 11:50:19 PM
Rules of the Road have nothing to suggest for you...that scenario should never happen. Even if transitioning from a red flash to stop-and-go, red and green should never be displayed simultaneously in the same signal face (5-section PPLT heads notwithstanding).
Does that apply to ramp meters too? I know Utah has/had some red/green (no yellow) meters that activated from dark mode by initially turning both the red and green lights on for several seconds. Took me a minute to figure out what was going on the first time I saw it.
The MUTCD chapter on ramp meters is surprisingly vague on ramp meter operation, including transitions into and out of metering status.
Meters are supposed to follow rules for signals except where otherwise stated in the ramp meter chapter. So from that perspective, the operation you describe probably shouldn't be allowed... However, I don't know how you would activate a two-section ramp meter display from inactive/dark other than displaying just the green that wouldn't cause an immediate panic.
Nevada also uses the two-section ramp meter heads. Interestingly, I've never seen a ramp meter turn on from inactive, so I don't know what the startup routine for ours looks like...
Quote from: ilpt4u on May 30, 2022, 08:33:59 PM
I went thru one on Rt 13 in Carbondale when it when it was switching from Blinking Red/No Power mode to "Normal" phazed operations (or vice versa): Literally had the Blinking Red and the Solid Green Ball on at the same time, the direction I was traveling. I went thru without stopping. And I still am not sure what the Rules of the Road suggest to do in that scenario
Quote from: roadfro on May 30, 2022, 11:50:19 PM
Rules of the Road have nothing to suggest for you...that scenario should never happen. Even if transitioning from a red flash to stop-and-go, red and green should never be displayed simultaneously in the same signal face (5-section PPLT heads notwithstanding).
The transition out of flashing mode should go to steady red and then greens for the major street/movement (assuming it's an all-way red flash) or the flashing yellows go to green for the major movement and the flashing red go to steady red (assuming yellow/red flash). The flashing red with a simultaneous steady green makes me think there was some kind of fault or issue with the signal (or, if that's a regular occurrence, it's older, non-compliant signal programming).
Not the area of my signal experience, but systems that employ traditional relays and/or contactors are subject to all sorts of failure modes. My understanding is that modern programmable traffic controller have a back-check of each relay/contactor that gets cross-checked with the outputs. If an unsafe condition is detected, the traffic signal is programmed to go into flash mode or be shut down. In my book, a traffic signal that has a stuck green should never go into flash mode. On the other hand, a traffic signal with a stuck yellow or a stuck red could be placed into flash mode (might be confusing, but shouldn't be unsafe). Plus, this type of a rule would need to be adjusted for signal heads that have flashing yellow arrows and perhaps other arrow arrangements.
Fun fact: On railroad signals, we employ "light-out-protection" as a back-check for any signal where a burnt-out bulb could be misconstrued as an improvement in the aspect. The classic situation is that a NORAC/GCOR red-over-green (medium clear/diverging clear) would be misinterpreted if the top red bulb was burnt out. In this case, it would be typical to downgrade this signal to red-over-red (with the top red still burnt out) and downgrade the approach signal to yellow (approach).
Just last week, I saw this signal (https://goo.gl/maps/7iQkFhUDcUMnbsN48) in the Port of Tacoma (along WA-509) go into flash mode. Any time a train passes on the right (short line rail road), the signal goes all red and then into flashing mode. Then all red, and then back to whichever direction. Takes a moment for traffic to figure it out, but eventually (within 30 seconds) people figure out what's going on.
Quote from: KCRoadFan on May 30, 2022, 06:59:16 PM
What's your experience with traffic lights and power outages? Do they come right back on when power is restored, or do the techs have to restart them?
Assuming it fully runs out of its battery backup before the power is restored, they just come back up into normal cycle when the power comes back on.
Quote from: connroadgeek on June 02, 2022, 08:51:57 PM
Quote from: KCRoadFan on May 30, 2022, 06:59:16 PM
What's your experience with traffic lights and power outages? Do they come right back on when power is restored, or do the techs have to restart them?
Assuming it fully runs out of its battery backup before the power is restored, they just come back up into normal cycle when the power comes back on.
don't the newer ones save there config to NVRAM / some disk / flash? and don't just keep it RAM or have an battery for config settings like an PC that can last for an long time?
Quote from: US 89 on May 31, 2022, 01:40:12 PM
Quote from: roadfro on May 30, 2022, 11:50:19 PM
Rules of the Road have nothing to suggest for you...that scenario should never happen. Even if transitioning from a red flash to stop-and-go, red and green should never be displayed simultaneously in the same signal face (5-section PPLT heads notwithstanding).
Does that apply to ramp meters too? I know Utah has/had some red/green (no yellow) meters that activated from dark mode by initially turning both the red and green lights on for several seconds. Took me a minute to figure out what was going on the first time I saw it.
some ramp meters are peak times only
Quote from: Rothman on May 30, 2022, 01:21:03 PM
Yep. Not sure of the actual intersections, but have seen a signal conk out on two separate occasions. Signal glitched and then went to flashing in both occasions, both as I was at the stop line in western MA.
Haven't seen one "come back to life."
I have seen one running very fast light cycles very fast like 30 sec or less greens for main roads and like maybe like 5-15 sec arrows.
Later in the day it seemed to have been fixed.
More related to the other answers was the time I saw traffic engineers working on a recent installation, a replacement due to a road widening. This was now the only light on the intersection, completely unhooded, but the engineers were turning on random lights or rapidly switching between green and red. There were several near misses, with one driver actually getting out and stepping on his running board to look around. The engineers seemed pretty indifferent to the chaos they were nearly causing.
Quote from: KCRoadFan on May 30, 2022, 06:59:16 PM
What's your experience with traffic lights and power outages? Do they come right back on when power is restored, or do the techs have to restart them?
Quote from: connroadgeek on June 02, 2022, 08:51:57 PM
Assuming it fully runs out of its battery backup before the power is restored, they just come back up into normal cycle when the power comes back on.
Quote from: Joe The Dragon on June 07, 2022, 12:11:17 AM
don't the newer ones save there config to NVRAM / some disk / flash? and don't just keep it RAM or have an battery for config settings like an PC that can last for an long time?
Sorry, microprocessors used in modern control systems don't work like rack-mounted industrial computers. But indeed, control system microprocessors utilize a non-DRAM fixed memory chip, but they usually boot/reboot off of the same memory chip. Typically, there is also a bootup bit calculation to determine whether the memory has changed. I don't know about traffic signal controllers, but most safety control systems run this same type of error check fairly frequently during runtime as a data/software error check mode (and if it ever fails, the controller shuts down). And as I mentioned earlier, there is a back-check (and cross-checks) of inputs/outputs to detect other faults and failures (which also is performed by traffic signal controllers).
3 times actually, two within the last six months.
First time was a while ago, and was not too surprising. I was a passenger and we came up to a light in flash mode. Clearly a malfunction, as it was the middle of the day at a busy intersection (so busy that there was a cop assisting with traffic flow) with no weather to speak of, and as we went through, someone from VDOT was working in the control box, so it was clearly gonna start working pretty soon. After we went through the intersection, I looked back to observe, and when we were about 50 feet clear of the intersection, the light came back into normal operation.
Second time was in January...late at night in a different state on a road trip and after we pulled off the highway to a place to stay, a light we were approaching (no more than 50 feet ahead) went from green to flashing yellow just as the clock turned 10PM, so I am almost certain it's nighttime operation because there was no weather (aside from it was less than 10 degrees), on a pretty minor and slow road, and it was working again in the morning.
Third time was recently with another malfunctioning light, but I was not in a car. I was taking a walk and one of the local lights seemed to be short circuiting or something...I saw it a couple times go from dark to flash mode to dark to flash mode every couple minutes. It was fixed by the next morning.
I actually caught one on video (as a passenger) on 22 Jun 21 in my hometown. The intersection of US Route 202 and River St sometimes tends to either go into flash (faulty MMU?) or even go out completely during heavy rainstorms or severe thunderstorms - it has happened twice in the same year. While I didn't catch it going from dark to flash, I did catch it going from flash to colours starting at all red.
https://www.youtube.com/watch?v=qxfjTGH9dOg
Here was a picture I took of the signal tech flipping it from dark to flash:
(https://i.ibb.co/LnjyqMZ/IMG-2567.jpg) (https://ibb.co/18yNp3m)
Good topic. This is what I observed.
1:30 a.m. - (My neighborhood in MD) Main street green, Side street red. As this is the beginning of flashing mode, the main street transitions to a solid yellow, a very brief red and then a flashing yellow. The side street flashes to red as soon as the main street flashes to yellow.
5:30 a.m. - (My neighborhood in MD) Main street FY, side street FR. Main street goes solid yellow, very brief red, and then green. Side street transitions to solid red as soon as main street transitions to solid yellow.
Ramp meters. In CA, some ramp meters are 3-aspect and some are 2-aspect. Sometimes both are displayed at the same time, with the 3-aspect up high and the 2-aspect at eye level. When a meter first comes on from no-power, it goes green, yellow, red (like a normal signal with relatively normal amount of time for each phase). Then, it goes red-green relatively rapidly (at the metering rate). When the meters go dark, the signals simply turn off after the last brief green aspect. So the only time I see a yellow signal on a meter is during the off-on transition.
[The ramp meters that they have recently introduced in MD do not go completely dark. They flash yellow when not in operation. I don't like it because there is nothing to be cautious of when going down a normal ramp. Also, they are confusing, since there are flashing yellow beacons at the entrance to warn of the metering lights. So one has to really be paying attention if the flashing yellow means that the metering is on (at beginning of ramp) or that the metering is off (in the middle of the ramp). I simply don't like it, and so many states like CA that have had ramp metering for years do fine with simply turning the meter lights off in non-busy times.]
Saw the signal at NY 277 and NY 354 go out and come on again back in December.
Quote from: roadfro on May 30, 2022, 11:50:19 PM
Quote from: ilpt4u on May 30, 2022, 08:33:59 PM
I went thru one on Rt 13 in Carbondale when it when it was switching from Blinking Red/No Power mode to "Normal" phazed operations (or vice versa): Literally had the Blinking Red and the Solid Green Ball on at the same time, the direction I was traveling. I went thru without stopping. And I still am not sure what the Rules of the Road suggest to do in that scenario
Rules of the Road have nothing to suggest for you...that scenario should never happen. Even if transitioning from a red flash to stop-and-go, red and green should never be displayed simultaneously in the same signal face (5-section PPLT heads notwithstanding).
I seem to recall the driver's manual for Oklahoma stating that any malfunctioning (including dark) signal is to be treated as a four-way stop. If I were to encounter this particular failure mode, I'd stop and then proceed only when it was clearly safe for me to do so.
Quote from: Scott5114 on June 24, 2022, 10:33:52 PM
Quote from: roadfro on May 30, 2022, 11:50:19 PM
Quote from: ilpt4u on May 30, 2022, 08:33:59 PM
I went thru one on Rt 13 in Carbondale when it when it was switching from Blinking Red/No Power mode to "Normal" phazed operations (or vice versa): Literally had the Blinking Red and the Solid Green Ball on at the same time, the direction I was traveling. I went thru without stopping. And I still am not sure what the Rules of the Road suggest to do in that scenario
Rules of the Road have nothing to suggest for you...that scenario should never happen. Even if transitioning from a red flash to stop-and-go, red and green should never be displayed simultaneously in the same signal face (5-section PPLT heads notwithstanding).
I seem to recall the driver's manual for Oklahoma stating that any malfunctioning (including dark) signal is to be treated as a four-way stop. If I were to encounter this particular failure mode, I'd stop and then proceed only when it was clearly safe for me to do so.
Bumping this thread, because this particular signal was doing it again tonight. I took pictures and a 10 second video (on a dark and rainy night, so not high quality). Only the IL 13 Straight Thru movements had Blinking Red + Solid Green. Protected Lefts from IL 13 and Cross traffic/Striegel Rd all had normal Blinking Reds. Tonight was at 8 pm CST, so way before "overnight" Blinking Yellow/Red mode, so not a standard mode transition
There was an IDOT truck parked next to the signal control box, fyi. Still odd that this is the second time I've seen this signal do it
I may get the pics uploaded to flickr and link them here later
Quote from: ilpt4u on February 08, 2023, 09:37:43 PM
Quote from: Scott5114 on June 24, 2022, 10:33:52 PM
Quote from: roadfro on May 30, 2022, 11:50:19 PM
Quote from: ilpt4u on May 30, 2022, 08:33:59 PM
I went thru one on Rt 13 in Carbondale when it when it was switching from Blinking Red/No Power mode to "Normal" phazed operations (or vice versa): Literally had the Blinking Red and the Solid Green Ball on at the same time, the direction I was traveling. I went thru without stopping. And I still am not sure what the Rules of the Road suggest to do in that scenario
Rules of the Road have nothing to suggest for you...that scenario should never happen. Even if transitioning from a red flash to stop-and-go, red and green should never be displayed simultaneously in the same signal face (5-section PPLT heads notwithstanding).
I seem to recall the driver's manual for Oklahoma stating that any malfunctioning (including dark) signal is to be treated as a four-way stop. If I were to encounter this particular failure mode, I'd stop and then proceed only when it was clearly safe for me to do so.
Bumping this thread, because this particular signal was doing it again tonight. I took pictures and a 10 second video (on a dark and rainy night, so not high quality). Only the IL 13 Straight Thru movements had Blinking Red + Solid Green. Protected Lefts from IL 13 and Cross traffic/Striegel Rd all had normal Blinking Reds. Tonight was at 8 pm CST, so way before "overnight" Blinking Yellow/Red mode, so not a standard mode transition
There was an IDOT truck parked next to the signal control box, fyi. Still odd that this is the second time I've seen this signal do it
I may get the pics uploaded to flickr and link them here later
I have seen this several times. The double illumination means the lamp driver has shorted and is always on.
One time I saw a signal with every lamp in the entire signal installation lit at the same time. I later found out lightning hit it.