Roundabouts have a long history. They have been existing and promoting for a hundred years. Nowadays they are used more often because roundabouts offer efficiency, road safety, flexibility. Via roadtraffic cars move slowly into the roundabouts. They organize on their own authority by visual communication. The passage stream is higher than the regulated trafficlights. For that reason this type of crossroads is putting into practice. This is a solution for the problematic crossroads, traffic calming, let through. Crossroads which are rebuilt into roundabouts mark clear decline of accident. The reasons are varied: The lines which cut across in the roundabouts are little compared to crossroads with traffic lighter. In addition roundabouts help to slow down speed. The rate of motion is 15 up to 30 km/h - speed that also provides accident and a better view over the situation for the driver. Even if accident happens damages are often insignificant. Other positive signs are non- stopping rate of motion, little noise and noxions emission.
Roundabouts are also adapted for trucks and when they are projected and built correctly does not exist any problem for big trucks, however security and efficiency don't decrease.