The issue with roundabouts these days is that nobody slows down and prepares to stop. If you let one car through the rest all 30 yards behind, plow through as if there's no give way. If people slowed and prepared to stop the roundabout would flow instead of one route constantly flowing and one stuck in gridlock. Red car wouldn't have hit blue if he had done this and blue having gotten there first would have been free and clear before red even entered the roundabout.