The Picard ManeuverAug 28, 2025
Make it make sense
Show threadYoSoySnekBoiAug 28, 2025

Most traffic jams actually act as a kind of compression wave moving backwards through traffic. Something as small as a squirrel running across the road can cascade into an hour-long jam.

One person brakes, then the person behind them, then the person behind them, but each time they are getting closer to each other (nobody stays equidistant from the car in front of them when braking). This causes a greater and greater slowdown as more cars are compacted into a tighter space, which travels backwards in traffic like a wave. Often the person who caused it doesn't even realize anything happened.

A lot of mapping software actually estimates a given traffic slowdown by treating traffic as a fluid with a wave moving backwards through it.

Show threadSibbo
Do you know of a paper that describes this kind of traffic motion?
Aug 28, 2025 at 1:44pmWeb
Show threadoddlyqueerAug 28, 2025

I couldn’t find the paper I was thinking of that described the phenomenon of traffic propagating as a pressure wave, but I did find this paper (new to me) that describes a model for simulating how congestion spreads in urban environments (as opposed to an isolated highway, which IIRC the paper that most people reference models). It does have the full text available though, and it looks like a good read and has references that should get you going on the history of congestion research.

I am not an expert; I just found this with a few minutes of searching. If there are experts with better papers I’d be happy to hear from ya!

www.nature.com/articles/s41467-020-15353-2.pdf

Show threadkubicaAug 28, 2025

I knew about the elastic band effect, but I was unsure if it was considered the same. But searching that I found about both:

https://en.wikipedia.org/wiki/Accordion_effect

https://en.wikipedia.org/wiki/Traffic_wave

Accordion effect - Wikipedia

Show threadoddlyqueerAug 28, 2025

Here’s the (abstract of the) paper I was thinking of pubsonline.informs.org/doi/abs/…/opre.4.1.42

Appalling that I can’t find a free version of a 70 year old paper. You might be able to find the full text somewhere… I would of course never encourage anything that might run afoul of the scientific publishing protection racket.

Show threadWappenNov 20
Not a paper but a great video I watched about it by braintruffle: youtu.be/m74zazYPwkY
Calm Traffic Needs More Than Calm Driving

To learn for free on Brilliant, go to https://brilliant.org/braintruffle/ . You'll also get 20% off an annual premium subscription.Traffic Jam Waves Are Coun...

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