[codeka]

> And in some circumstances four-way stops flow more traffic.

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?

I'm pretty sure it's purely cost-cutting. Four way stop signs are extremely cheap compared to roundabouts. There's no other advantage that I can think of.

Roundabouts are safer (there is no opportunity for t-boning at a roundabout), faster and simpler to navigate than four way stop signs (a roundabout you just give way to people already on the roundabout, a four way stop sign requires you to keep track of who arrived first and then do a weird dance if you both arrived at the same time, and you still need to watch out for people attempting to go out of turn -- which is not possible with a roundabout)

[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.

[nitrogen]

There's a 6-way roundabout I know of that frequently has one of the 3 intersecting roads dominate the traffic, so people just go full speed from that road. In that case, the other roads can be completely starved, so a 6-way stop would have been better for those roads in those times.

As for t-boning, you can definitely have someone enter a roundabout early/late and hit another car on the side, or dart in front of a car that's in the roundabout (especially possible if the roundabout is not perfectly circular) and themselves get hit on the side.

And people manage to go "out of turn" in roundabouts all the time, by not yielding, or by tailgating.

[matthewdgreen]

Roundabouts can also be a nightmare for pedestrians.