Traffic is a compression wave.  You brake, then the person behind you brakes, then the person behind them, etc.  You accelerate, then the person behind you...<p>Highways that become automated-only will not have this problem.  The cars can communicate with each other and change speed in unison.  You don&#x27;t even need to convert a whole highway, you can just reserve a single lane for automated cars and get most of the same benefits.