Most don't even know the right of way rules on a roundabout.
Quote:
Giving way
Slow down as you approach a roundabout. You must give way to traffic already on the roundabout if there is a risk of collision. Enter the roundabout when there is a safe gap in the traffic.
Many drivers apparently believe that if they are on the right and approaching a roundabout, they have right of way over someone who is already entering the roundabout on their left.

