The trick I keep in mind in situations like this is to look at brake lights ahead of me. If cars are braking and I'm accelerating, I'm probably going to end up driving very inefficiently. By letting off the accelerator, I don't close the gap as quickly, and eventually, the turbulence in the traffic flow steadies out. Instead of stopping and starting, I roll at an averaged out speed, which doesn't feel as frustrating (it's kind of relaxing) and is better for fuel economy. There are, of course, the weavers who jump from gap to gap, tailgating and pushing. Sometimes it works, sometimes they just get jammed up.

I don't drive as often as I used to, but on I-76 coming into or out of Philadelphia, traffic gets snarled and becomes stop-and-go. Every now and then, someone next to me appears to have the same understanding of fluid dynamics as I do, and we build up enough of a buffer that we are able to eliminate the stop-and-go, even if it means rolling at 5mph with a big gap between us and the cars in front of us.

There's no good way to communicate what we're doing, even to each other. But I like to think that when this happens, it has a positive effect that ripples out for miles.