If you want to avoid traffic 'waves', so all vehicles accelerate and decelerate at the same time, you must remove _everything_ that might introduce unexpected variance.

Which basically removes people.

A simple fact is that faster moving traffic is necessarily less dense; the gaps between vehicles must be larger to account for small variations that matter more and more at speed.

I'd say it's more about reducing unnecessary stoppages where possible. The wave is triggered by someone braking ahead for whatever reason, we're looking to prevent the unnecessary wave, not necessarily stop the initial braking event as it may have been necessary.

Let's improve driver's ed and impose more licensing restrictions. Seems like pretty wide variations in standards between States.

Let's ban distracting billboards in more States, as in Maine, Vermont, Alaska, and Hawaii.

Let's expand annual vehicle inspections to more States.

More surveillance tech, automation, and regulations aren't the answer.

> you must remove _everything_ that might introduce unexpected variance

I'm not sure that follows. Cars that communicate can accelerate and brake together even in unexpected situations.

You need the increased space, which means you have the traffic waves.

You need the space because of variations in cars; some have better brakes than others, some may be heavier so need more time to slow down, others may be on wetter patch of road, etc.

And one car may not even get the signal, so only slows down when it observes the vehicle ahead of it doing, an observation that needs time.

Or a car starts accelerating as the one in front just stalls.

It may all be better than human reaction times, but for robustness, which is really very necessary, you're going to get the same dynamics.

And this all assumes only good actors; somewhat optimistic in my view.

Waves are caused by starting at different times, and connected vehicles can coordinate their start time. Yes, you need more space with speed, but a fleet can handle that with different acceleration curves instead of varied starts.

This isn't entirely true, connected vehicles would still have some delay due to radio propagation time, but it's ns per vehicle instead of hundreds of milliseconds. Additionally, you can entirely compensate for it in ways you really can't with humans.

Also a connected vehicle could potentially tell much if the car ahead is actively accelerating. Reducing it's need to brake if it can tell there's sufficient distance to negate braking (a bit more risky).

> Cars that communicate can accelerate and brake together even in unexpected situations.

A horde of cars where 100% of them consistently operate in a failure-free state and have comms that can't be hampered by the environment - that group could maybe do this.

Fair. If coms fail though, you're no worse than today. Vehicles don't need to travel any closer, just start together.