> If the point was the reduce the flow, why wouldn't you make a roundabout?

Roundabouts have far higher throughput than junctions with traffic lights.

Not quite, traffic lights have the highest throughput if done properly (by quite a margin), but compared to the US style of lights they do.

But only because they allow for higher density, not higher speeds, which it seems GP was discussing.

> Strange! Where I live traffic lights are used for the opposite purpose: they are set up to improve flow by creating green waves that mean ypu don't have to care about orthogonal traffic.

story: An out of state tech visiting our job site greeted us with "What the hell is wrong with the traffic lights in Florida!?" This was SW FL and I was a little confused because he had driven thru one of the most benign counties. I might be conditioned though.

Just north of Tampa is a county where most traffic lights are timed to insure you reach the next one on the yellow. I've traveled thru it regularly for 30 years. Between 20 and 15 years ago it reached ~as bad as possible status and there it remains.

Adding awful to bad are the drivers who've realized they can defeat much of this timing with sufficient speed.

That is what should be done, but it’s becoming rare. Bangerter Highway in Utah comes to mind as a good one. I know Colorado is a state big on vision zero policy, where if you go the posted speed you will hit every single light.