[rootusrootus]

> There's no way that's true, is it? What circumstances would a four way stop sign allow for more traffic flow than a roundabout?

Heavy traffic. In most situations a roundabout will do better, but when completely saturated, the 4-way has a slight advantage. This is probably due to how 4-way stops with dense traffic develop an predictable alternation pattern that eliminates ambiguity and reduces the clearance requirements.

[macintux]

What I've seen here is that traffic will sometimes back up into the roundabout from a blockage down the road, and then things grind to a complete halt, which a 4-way stop should never suffer from.