I think the diverging diamond interchange is terrible. Because of the crossover, traffic can only cross the interchange in one direction at a time, so most of the traffic in the interchange is not moving most of the time.

A pair of roundabouts connected to on ramps eliminates the danger of left turns without stopping the majority of traffic most of the time.

A massive overbuilt interchange that cannot function without traffic lights is the opposite of elegant.

[–] grue@lemmy.world 3 points 3 weeks ago

Because of the crossover, traffic can only cross the interchange in one direction at a time, so most of the traffic in the interchange is not moving most of the time.

I'm not so sure about that. The appropriate use of a diverging diamond is when there is a lot of traffic entering and exiting from the ramps, and some of that traffic can go at the same time as the traffic crossing the interchange in one direction.

[–] lud@lemm.ee 1 points 3 weeks ago

I don't live in the USA but don't these mostly replace intersections that already have traffic lights?

Also there is a proposed variant without traffic light called DCMI but I don't think there has been any build due to patents or something.