It's incredible to watch the emergent behavior out of real world systems. Completely counterintuitive, and yet there it is - a clear backward propagating compression wave, whose speed probably mostly depends on human physiology (e.g. reaction time, personal comfort level with distance to next vehicle, etc.) Fascinating.

>whose speed probably mostly depends on human physiology (e.g. reaction time, personal comfort level with distance to next vehicle, etc.)

I think it has more to do with the suddenness of the stop; each car behind it has to stop suddenly in response, as the change only spreads locally. I’m pretty sure all you need to modify is deceleration speed for braking and acceleration speed to catch back up, to see like 90% of the effect

I’d test it with the simulation but it was too difficult to setup on mobile :-)

> each car behind it has to stop suddenly in response

Yes. And simply maintaining good following distance gives you a buffer that can absorb this sudden change and prevent the tailback. This is one of the reasons that I long for the day that humans don't pilot cars on the highway.