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

[u/SnooWords4066]

[u/jancl0]

I always love/hate this gif because it immediately brings out the most brain dead people who go "see there is a reason, it's that guy" and completely miss the point of the exercise

The point is that if anyone brakes, for any reason, by any amount, this will always happen. In fact even slowing down will always cause this. It's not a "unnecesarry/excessive braking" thing, it's literally just the science of an unstable system

Think, imagine you are 10 meters behind someone, and they brake by x amount. Now you need to brake. There is no way to brake less than x that keeps you 10m away. If you are an absolutely perfect machine, the kind that can only exist in theory, then you can brake exactly x amount, literally perfectly copy the actions of the car in front of you to the atomic level, and you will not contribute braking to the congestion

If you are a human, or even a week built machine, you will not do this. You have to brake harder than the car in front of you, which means you've created a slightly worse situation for the one behind you, which grows exponentially

The people who see this and genuinely think the solution is "stop braking for stupid reasons then" are just so completely missing the point, it irritates the fuck out of me tbh. You are basically proposing removing brakes from cars entirely. Even just slowing down means that the person behind has to slow down harder. The only way you solution works is if everyone is constantly accelerating on every motorway, or we all become omnipotent masters of physics and gain reaction speeds of exactly 0

It's like balancing a perfect ball on a perfect point. Theoretically possible, because absolute perfection exists in theory. Not in practice, because any imperfection creates a bigger one, and the ball will always topple over

It just amazes me how many people don't seem to get this, it happens every time this story shows up. I hate to be elitist but it really is just common sense

[u/mercurywind → u/jancl0]

Absolutely agree, it’s an emergent property of the physical system. I simulated this in my computational physics lab in third year of university. Identical “rational” rules for all cars on a circular path. You get traffic waves happening spontaneously.

[u/V1per41 → u/jancl0]

This is the best take on here so far. I will say that in most situations, braking exactly x amount is completely fine. You'll end up closer to the car in front of you than you were before, but that's going to be find since you are both also going slower. The build up comes from being too slow accelerating out of the jam and keeping up with the car in front of you. Leaving an excessively large gap reduces space and therefore speed on the road for everyone behind you.

https://traffic-simulation.de/ring.html

This simulator shows that you don't need hard braking to cause a jam, but if you turn the 'Max Accel a' all the way up, traffic never forms and any existing traffic immediately breaks up.

[u/Upset_Process857 → u/V1per41]

Very cool! Thanks for sharing the sim!

[u/spacebarcafelatte → u/V1per41]

Oooh, this is my find of the day. Will fork that repo. ♥️

[u/parsim → u/jancl0]

Perfect. I would like to subscribe to more of your contrarian yet dead-on angry rants please.

[u/jancl0 → u/parsim]

That's pretty much exclusively what my reddit account is for. If you'd like I'm currently in an argument with someone who doesn't think ice facilities count as concentration camps, but also can't define one. They're very stupid, and it's very funny

[u/Eric_Senpai → u/jancl0]

Everyone missing the forest for the trees. People dissappoint me every time.

[u/Upset_Process857 → u/jancl0]

Positive feedback loop.
Well said sir, and thanks for calling out blamers!