> The tradeoff for the compression 'vanishing' is longer times pressing your breaks, travelling slower overall, and leaving your engine running for more of the time.

What? Your travel time does not get longer, and if the traffic is merely slow then this "leaving your engine running for more of the time" is nonsense. Even if it's stop and go and you have a car that kills the engine every time you come to a dead stop, that will use more gas because you're making inefficient use of the electrical system (charging and discharging the battery more than you should have to).

> Also you then just leave a bigger gap in front of you for somebody to jump into,

Sure, so as earlier you have to pay attention and not allow that.

> In heavy traffic I much prefer to quickly catch the car in front up and then sit stationary with my engine off. Much more efficient

Doubt.

And besides doubting your claim about efficiency, you're doing exactly that which most helps the pressure wave endure, and thus you're causing more delays for more people, and more people to have to brake hard, and more engine stop/start cycles, all of which means more pollution overall not less, etc.

You really have to think systemically.