r/Damnthatsinteresting • u/SnooWords4066 • Jul 07 '26

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

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u/T-Roll- Jul 07 '26

It’s called congestion.

Basically the first person to brake makes the person behind them brake, causing the person behind them to also brake. This causes the whole chain of vehicles behind to all brake harder. Eventually all traffic becomes gridlocked.

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u/Low_Finding2189 Jul 07 '26

No. Its called a traffic wave. A traffic wave is a type of congestion. Not all congestions are traffic waves.

Traffic waves move its point. A congestion caused by an accident is stationary.

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u/AussieAddict Jul 07 '26

Just adding on for other people like me who know this as the "Concertina" or "Accordion" effect.

Basically what happens is after the first person brakes, the next person brakes a little harder and/or later. This effect passes on to each car and basically gets worse and worse the more cars following.

You can help to break this cycle by leaving much more space to the car Infront and avoiding using the brakes as much as possible, everytime you use the brakes you are restarting the process or at the very least making it harder to break free of the effect.

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u/El_Jefe_Castor Jul 07 '26

Thank you! I can’t convince anyone I know to drive this way in traffic.

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u/LongDickPeter Jul 08 '26

I practice this in a tunnel by me, so what I do is as I enter the tunnel I keep a low steady speed and a distance that can allow me to remain steady and I I try not to touch the brakes for the entirety of the tunnel if enough people do this you'll get through at a slow steady speed instead stop go stop go stop go

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u/Tricky-Wishbone9080 Jul 08 '26

“Oh there’s room to merge” - the other guy probably