Definitely a good way to go, but it doesn’t really improve throughput. If that gap ahead of you means not getting through an intersection before the light changes, it just backs up traffic more. That’s worthwhile to me when you consider things like higher fuel efficiency/less wear to drive a consistent speed vs stop and go, lower chance of collisions since you’re allowing a greater following distance.

It’s actually similar to the till line issue. When you have multiple tills open with multiple lines, you can get people through faster than having a single line that breaks out to multiple tills. People prefer the second case though because it feels like the line moves faster and it feels more fair because nobody has to be the one that ends up in a line moving slower than the rest. Traffic would probably flow better if more people just let themselves follow the flow instead of fighting for a good position, but the effort spent finding ways to advance through traffic makes people feel like they’re making more progress.

It doesn't work because nobody else does it. I'm stuck in traffic with a bajillion people and 99% of them either brake or gas, no coast. In some ideas scenario where everyone does it, sure, but in real life it's a no go. But I still do it.

Hypermiling is silly.