[jedberg]

Those traffic waves are in large part psychology though. If every car traveled at the average speed you wouldn't have them. If even just 10% are self driving and have data on average speed for that section of road, they can not only avoid the wave but break them up, making traffic better for everyone.

I've even done this myself. I see a standing wave in front of me and slow to what I know is about average for that time of time. People cut in front of me as the gap gets bigger, but by the time I get to the choke point the wave dissolves as I pass through, and everyone behind me who was pissed about my slow speed is suddenly happy.

[saosebastiao]

I'm not convinced, and I don't think there is very much evidence either way. Are the traffic waves caused by erratic driving due to driver error at misjudging average speed? Or is it more caused by small fluctuations due to actual and unavoidable conditions? Would a self driving car see a plastic bag blowing in the wind and slam on its brakes, or drive right through it? What about a kitten? What about a bowling ball, or an unsecured 2x4 falling off a truck? Any one of those situations can cause a shock wave.

We know, due to fluid dynamics simulation, that reduced reaction times will make traffic more resilient to small fluctuations in speed (they can "recover" from the shock wave with lower space requirements), but when the freeway is at capacity there is no recovery room and the shock wave will happen regardless of reaction time.

[bashinator]

I try to leave 10-20 car lengths between myself and the next vehicle in this kind of stop-and-go heavy traffic. No waves for me! The anti-traffic essays indicate that doing what I'm doing will actually speed up the breakup of a traffic jam.

[galdosdi]

That's true, but depending on the local driving culture, this may just lead to many vehicles cutting in front of you and making the gap vanish. In metro NY/NJ, at stop-and-go speeds on freeways, 1 to 2 car lengths seems to be about as much as you can safely leave without it quickly being snatched away. Too bad.

[bashinator]

Cars cutting you does not make the gap vanish - you just have to slow down marginally more for a short amount of time.

[crucini]

This is an interesting insight. What if we replace 20 sequential cars with a huge "road train" ala Australia - a tractor with multiple trailers?

The road train has no cushion (ignore the few inches in pintle hooks) so it brakes as a unit. And accelerates as a unit. Does that make it's recovery from shocks 20x as good as 20 cars?