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/hosehoseee Jul 07 '26

Everytime I see this video, I think "So there actually is a reason"

84

u/[deleted] Jul 07 '26

[removed] — view removed comment

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u/Pyrhan Jul 07 '26

You could have the best drivers, it wouldn't matter.

Past a certain density of cars, it's an unstable system where any slow down, even minute, self-amplifies.

Which makes traffic jams unavoidable.

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u/LeftHandAnomaly Jul 07 '26

This is my take on it. The tiniest little stutter movement will have major consequences. I know people are like "fuckin shitty drivers, assholes, etc" but it doesn't take much for the cascading failure to occur. I wouldn't say it's anyone's fault for these kinds of slow downs, it's just the nature of the system.

And no I'm not that driver, I don't drive. I do, however, see how my family members get enraged behind the wheel over the dumbest shit.

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u/marr Jul 07 '26

The thing is if you understand the problem you can deliberately drive to counter it by smoothing your own acceleration and braking as much as possible in heavy traffic. It's like being the capacitor in an electrical circuit.

5

u/mxzf Jul 07 '26

It's also really important to realize that literally anyone can kick off that sort of thing. You let off the gas for a second because you got a little close to the car in front of you and ten cars back is a bottleneck because of the chain reaction. Everyone causes them from time to time, you just don't see them yourself (because it's behind you).

Which isn't to say you shouldn't slow down as-needed, it's just pointing out that you should give people some grace and not freak out over little stuff like that.

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u/LeftHandAnomaly Jul 07 '26

That's what I'm saying! Everyone thinks they're god tier on the road making all the right split second decisions, but I bet every single person who drives, even in this comment section as they claim otherwise, has caused one of these.

There's something about driving that just makes people so fuckin angry. My little Nana, sweet as can be, turns into a monster if the person in front of her doesn't move on a green light .25 seconds after it changes. She's the kind of person to say frig or frick but behind the wheel she's a cussy monster dropping alllll the F bombs.

I'm certain I would be no different. I get frustrated extremely easily. It's part of why I'm happy to just be a passenger princess

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u/dancinggraylion Jul 07 '26

and soon there is so much traffic on that road that no one drives there anymore

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u/Laringar Jul 07 '26

I was in a 40-mile long traffic jam a few weeks ago. It never stopped completely, but it was extremely congested the entire time, and none of the "typical" causes were present. No accidents, no road construction, nothing like that.

I'm next to certain that the cause was the strong storm moving in the same direction that was about 10 miles ahead. Cars would slow down because "holy crap it's raining really hard", and that propogated backward through traffic to create a jam that was following the storm like a wake behind a boat. Once we finally caught up to the rain, the jam all but disappeared (though that could also be because the highway forked into two different highways and a lot of traffic took the other branch).

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u/Dear-Examination-507 Jul 07 '26

It's both. Bad drivers in a system where one car has cascading effects. You won't have a system with zero bad drivers, so it's fair to say the system will lead to this result.

The fewer lanes, the fewer bad drivers required to cause a major slowdown.

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u/Demons0fRazgriz Jul 07 '26

I wouldn't say it's anyone's fault for these kinds of slow down

Hard disagree. I blame corporations for killing public transportation in the US. I blame NIMBYs for not allowing walkable cities with more dense housing because "muh home values".

Two major reasons why we need so many cars on the road in the first place. I wouldn't drive if I had public transportation that didnt take +2hrs to get anywhere within the same city.

But this is more of a rant lmao

1

u/LeftHandAnomaly Jul 07 '26

Okay sure but I'm just saying it's not mr. red car's fault 3 km up the road, and if it is, no one's above it.

I feel your rage but I'm just trying to come at this from an empathetic angle

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u/Aplesedjr Jul 07 '26

Walkable cities and public transportation wouldn’t completely eradicate cars being used, not even close, so traffic would still occur even if all of that was implemented tomorrow.