Just spent some time in New Zealand where they have lots of roundabouts and really learned to like them, when properly constructed and signed. Most of the ones in the states are not built correctly, they are way to small, it seems like the DOT's build them within the same right of way as a regular intersection. Then they build up the middle to where you cannot see the on coming traffic and reduce your reaction time to on coming traffic.
At the Spring Rally this year we encountered several of these good old roundabouts. On the east side of the freeway as you head to the casino you have to pass through two of these wonderful joys. They are literally one after the other. One would have been too many but they then put another one 25 yards from the freeway exit one. Crazy! Crazy! Later, Dennis