People using the road make mistakes, always have and always will. Crashes will always be with us, but they need not result in fatalities or serious injury.      Modern roundabouts are the safest form of intersection in the world - the intersection type with the lowest risk of fatal or serious injury crashes - (much more so than comparable signals).  Modern roundabouts require a change in speed and alter the geometry of one of the most dangerous parts of the system - intersections.  The reduction in speed and sideswipe geometry mean that, more often than not, when a crash does happen at a modern roundabout, you usually need a tow truck, not an ambulance.  Roundabouts are one of nine proven road safety features (FHWA).  
The life saved may be your own.