From New Scientist Shockwave traffic jam recreated for first time.
Yes, when a car taps its brake and a road is at capacity, shockwaves ensue. Yes not all drivers are identical, and yes some drivers are random. Candidate for Ignobel prize?
In real life, we don’t drive on circular test tracks, and there are gaps, allowing traffic to eventually recover. One could have looked at race cars for a similar experiment.