After reading through various threads in the 3 years I've been on this forum it looks to me like the vast majority of accidents are coming off roundabouts in the wet and yes, I lost it on a roundabout many years ago luckily without hitting anything. Roundabouts create a fairly unique set of problems, first of all they nearly always have a double change of camber, which can make the car "go light" coming off the second change. Next, roundabouts are one of the most likely places for diesel spills due to camber changes I would imagine. These are the places that will see motor cyclists come off and trucks shed their load. There is a roundabout near to the Broughton retail park that had a truck tipping over almost weekly until it the camber was taken out of it. Many roundabouts are surfaced in one go, obviously in a circular pattern, but the roads that join them are tarmaced in a straight line. Where the two join there'll be a difference in grip and in some cases even a different surface, for example when they built the A55 it had a concrete surface, but all the roundabouts were asphalted. Of course, nearly all roundabouts are low speed, low gear and this is where the tyres will take a much larger lateral load and if it exceeds the tyres limits..well you're in trouble.
Pete