[bradstewart]

For reasons that are unclear, a lot of roundabouts in the U.S. are so small that its nearly impossible for two vehicles to be in the roundabout at the same time.

Which makes them basically useless, and difficult navigate for e.g. vehicles with trailers--you end up running dragging the trailer over the center or something.

[kwhitefoot]

Small roundabouts in Europe are typically just a disk of white paint in the middle. Anything too big to go around just drives over it.

[actually_a_dog]

There are a lot of these in Berkeley. On top of being small, they have stop signs at the entrances, too! I tend to believe they're mostly an excuse to put a tree in the middle of the road, because a lot of them do have trees in the center.