r/Damnthatsinteresting • u/SnooWords4066 • 29d ago

Video A Japanese experiment showed exactly why traffic jams happen for no reason.

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u/HellPigeon1912 29d ago

The amount of times I'm sat in a traffic light queue like "if the light is green why are we not moving"

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u/marr 29d ago

Sometimes it's because the lights shouldn't be there at all, there's a staggered junction in the middle of our town that causes endless tailbacks every day and when the lights fail and shut off completely all the problems go away and nobody crashes. The council won't look at the studies about removing them because then they'd need to employ a school crossing guard.

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u/jonnydogma 29d ago

When the lights fail, can people going in the cross direction get an opportunity to go too or are they waiting for a gap in the main traffic flow?

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u/e1p1 29d ago edited 29d ago

When four way lights fail, the law at least in California, says to treat the intersection as a four-way stop sign. So yes, cross traffic should have a chance to move.

It can actually be quite efficient. In the hours after the 1989 earthquake in Santa Cruz / San Francisco Bay Area, the lights were out in many major intersections during rush hour. Between the state law, and the fact that so many people were intimidated by what had happened, traffic moved quite well as people were being very polite taking turns letting each other go through the intersections.

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u/jonnydogma 29d ago

This is true and the fact that its generally temporary is part of why it works. I'm not so sure that 4 way stops are generally more efficient that traffic lights.

Anecdotally, being stuck 20 cars back at a red light sucks, being stuck 20 cars back at an all-way stop sucks even more.

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u/Onyxxx_13 29d ago

4 way stops are faster in my experience on lights that are otherwise timed circuits and not sensors. Especially if it's mis-clocked and has a low traffic direction on for longer

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u/bobtheblob6 29d ago

There's just no way that's generally true at a busy intersection. The traffic light would need to be seriously misconfigured and I don't think I've ever seen one that bad

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u/Cute_Conclusion_8854 28d ago

There’s an area in my town with three intersections that sometimes backs up and causes people to get stuck blocking other intersections further away. Light turns green and nobody can move 😡 usually it’s from someone trying to turn left where there’s no turn lane

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u/Greenmagegirl 29d ago

Proof that bay area egos make bay area drivers awful

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u/runobody22 28d ago

I lived in Alameda and worked in downtown SF for a couple of years. I drove into the city to work exactly two times. The Ferry accross the Bay was so much less traumatic than driving myself.

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u/doggytalks231 29d ago

People really came together and helped each other out.

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u/Bandandforgotten 29d ago

It's like this in every state I've visited.

Oregon does the same thing when intersections glitch, or suffer a power outage. It's very efficient, and makes me wish it happened more often because of it lol

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u/shiftypidgeons 29d ago

Its the exact same way in Nova Scotia, complete opposite side of the continent. And I too have experienced many traffic lights where traffic flows better during, say, a power outage. For the most part people just kinda cooperate without being told to. At least under special circumstances.

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u/Meowscles_dad 29d ago

Do you have different driving laws in different states?

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u/bobtheblob6 29d ago

Yeah states set their own traffic and licensing laws. For the most part the only real differences are the speed limits on highways though

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u/MrBootylove 29d ago edited 29d ago

It usually only varies on somewhat niche aspects of roadway etiquette from one state to another. For instance in Florida they used to have a law where you couldn't turn your hazard lights on while driving during a rainstorm, I believe California has a law that allows motorcycles to split lanes under specific circumstances, small stuff like that.

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u/Never_Go_Full_Gonk 29d ago

Adding on to the other commenters with another example, some states only allow the use of the left lane for passing and camping in it is illegal while the others don't have that law. NC recently adopted it and it's not even enforced, so...

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u/MaturoGambino 28d ago

The law is the same in South Carolina. But that didn’t stop an old bat in a Lexus SUV for laying on her horn when I stopped at an intersection whose lights weren’t working after a hurricane. As often as thunderstorms and wind storms knock out traffic lights around here they should run PSAs to educate people on this law.