What to do when traffic lights transition to a different mode of operation?

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I was at a metering light waiting to get on a freeway. It might have been 7:05 PM, so I'm not sure if the time was important. However, I saw the car in front of me going on a green, then the light turned red, and then all of a sudden all the lights went off. I wasn't quite sure what was going on, but when the drivers behind started honking I figured the metering lights just turned off. I've also been right there when at certain intersections the standard traffic lights turn into flashing lights. Sometimes this seems to be some sort of manually selected mode, but I remember in my hometown all the traffic lights in town would operate like that late night between maybe 11 PM to 6 AM. It did occur to me that it gets kind of odd around the transition, like when I was stuck and I wasn't sure if I was supposed to go or not. And when it all changes I'm thinking some drivers might not get what going on an either stay there or maybe even do something stupid like enter on a flashing red when the other direction has flashing yellow.
 
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If there's an obviously minor road, that one should stop and the other should proceed with caution. Otherwise it's a 4-way stop. I'm curious how they start being a traffic light again. Obviously there should be a second where they're all full-on-red before the major road gets the green.
 
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The metering lights I'm familiar with only operate during certain preset busy times of the day. Outside those times, the lights are off and you proceed as if there is no light at all. Power went out last night by me and the traffic lights were out. It was the wild west. Late at night when the lights flash, red flashing is a stop sign and yellow flashing is proceed with caution. This was basic stuff in drivers ed 40 years ago.
 
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I've seen odd glitches happen like that, too. If the power flickers, the traffic lights often go into some offbeat mode. I remember years back, when everything was based on time of day, something must have gone wrong here. I was driving cab at around 5:00 a.m., and all the lights were acting like it's 5:00 p.m. There were long turning arrows with no one being out and about.
 

y_p_w

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I don't think that power outages really affect a lot of the newer lights. Or at least they're not supposed to . I remember a couple of decades ago when LED arrays started being used, the rationale for the expense was that they would likely never need replacement, and that they used so little power that battery backups were more practical. Even then I've seen lights go out when there was a major power outage.
 
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The metering lights should just go to green or will shut off (usually there's a sign indicating that nearby) when they aren't needed any more. This isn't always a timer. They will use sensors for ramp traffic and receiving highway volume to determine whether the light is needed. It looks like you had one like that. With the LED lights and congested intersections they've been using battery backups that will last hours. They have a few around me. The LED's proved dangerous over the winter when we had a heavy, wet snow.
 
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Originally Posted by SevenBizzos
The LED's proved dangerous over the winter when we had a heavy, wet snow.
Yes we have that problem in Wisconsin as well. It's surprising how little light and color gets through heavy snow.
 
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By law, when a traffic light is unlit, you are supposed to treat it as a stop sign. Seems legally it should stay green or flashing yellow when not metered (or have some signage indication that stopping not needed if no lights on), otherwise you could theoretically get ticketed.
 

dishdude

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They only use the lights during rush hour, other times it's just treated as a yield sign. The guy in front of you caught the tail end of rush hour metering, it turned into a yield sign for you.
 
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When I lived in Colo Springs, heavy fog would cause the turn lane sensors to go haywire, and the lights would act as though a car was present in the left turn lane at all times. This caused a super long turn arrow with no traffic in that lane, in turn causing the straight lane to back up something horrible. I caught them many times in this condition right at rush hour in the morning on very busy stretches. Most cars would just run the red light after figuring out there was no cross traffic. It amazes me that traffic controls are reliable as they are, I often wonder how they got away with the primitive "dumb" lights of 20+ years ago.
 
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A local town used to do that, from 11pm to 5am the traffic lights were preset to flash yellow.... So if they are fixed on yellow flashing, is that a yield or a 4 way stop?
 
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Not quite the same issue here, but some intersections on my way to work were upgraded with right turn arrows for when the cross traffic was on a left turn only cycle...this has helped traffic move a lot better during commute times. Only problem is that they didn't bother to add a yellow on the right turn arrow, the green just disappears. Even though it has been this way for a while, it still surprises me for the turn arrow to abruptly go from green to nothing...my immediate urge is often to brake to a stop if I am about to turn when the treen disappears, but I feel that would be dangerous if there is any traffic behind me and I will just proceed with caution unless I am far enough back that I think the cross traffic will be starting up as I am turning. Seems to me that there could have only been a tiny cost savings involved with not having a yellow on the turn arrow and that it would have been better to spend a little more money. Haven't seen an accident at any of these lights yet....IDK, maybe I'm the only one who gets irritated by them.
 
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Originally Posted by y_p_w
I've also been right there when at certain intersections the standard traffic lights turn into flashing lights. Sometimes this seems to be some sort of manually selected mode, but I remember in my hometown all the traffic lights in town would operate like that late night between maybe 11 PM to 6 AM.
If you're talking about the I-80 ones between Crockett and Oakland, I think Caltrans D4 on Grand Ave. turns those on just before commute hours. I've seen detector grids on the on-ramps but it seems like they are using data from FasTrak and the randomly placed detector loops to gauge when to time the metering lights. The carpool ones tend to be more liberal to let carpools and buses onto the freeway. The cabinets that control those lights have a controller, DVR for the cameras overhead and a Cisco WAN router. I think those are running 4G LTE modems so they can communicate with Caltrans. The MTC in San Francisco also has access to that feed. Oakland for the most part is still using "metered" stop lights. I think ACTC forced them to add cameras to each stop light to trigger them. I think these might be a better solution: https://www.trafficware.com/detection.html
 
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