RogerWilco--My point is, there is no uniform rule in the US. Some states do not even have uniform rules. New Jersey had none, and what I told you is what was literally on the law books at the time that I lived there. In some places, you yield to the traffic already in the circle, and in others they are expected to yield to you.
Well, no offense, but I don't believe that. Priority to the right is the fundamental rule all individual traffic relies on (or I assume priority to the left in British and British-"inspired" countries) and that rule is in place on any roundabout that doesn't have signs saying otherwise too.
Priority is to the right here too on a roundabout - the idea being that two people approaching on opposite sides of a roundabout can both go at once because they'll pass on opposite sides of the roundabout. The only time that doesn't work is when people drive over mini-roundabouts instead of round them.
There is a mini-roundabout near me, and I've lost count of the number of times where I've had to stop on it because some idiot failed to yield to the me (I was entering it too their right). One would think they might be more careful saying the local Police Station is around 100yards away.