Growing up in the Northeast, I have always had to navigate rotaries and roundabouts. They do have a positive impact on traffic flow; something my California wife doesn't comprehend. Visitng the in-laws recently, I was enthused to see former intersections converted to roundabouts, while my West Coast family repeatedly harped about how inconvenient they are.

Where I've always had issues, and near misses, is when motorists entering a rotary fail to yield to traffic already in the circle. They fly in either unaware or with complete disregard of the yield sign forcing rotary traffic to yield to them. Perhaps they are transplanted European motorists who are used to having rotary traffic yield to the incoming traveler :)

I've never seen a European rotary that forces circling traffic to wait for new entries. The whole point is that the system is self draining. New traffic only enters when the circle starts to empty.