A roundabout is a traffic structure, where the movement of a vehicle is defined by the central circular island and circular roadway, and with the dividing islands and traffic signs. The first signs of intersection with circular traffic flow as a form of structural elements were seen at the beginning of XX. century, long before the domination of motor traffic. It's estimated that over forty thousand roundabouts have been built in the world today. This increase can also be felt in Croatia, where roundabouts are becoming increasingly important. Due to the large increase in traffic in cities, roundabouts are the ideal alternative solutions for designing and planning intersections due to many of its advantages. If they are properly applied and shaped, they significantly contribute to increasing the intersection capacity and level of service as well as increasing the degree of traffic safety due to the small number of conflict points. During the exploitation, they reduce the total travel time, the waiting time of the vehicle at the intersection, fuel consumption, and reduce the environmental impact by reducing exhaust emissions.