Small roundabouts have become very popular in Norway during the last ten years. The total number of roundabouts has increased from about 15 in 1980 to about 350 in 1990. The success of small roundabouts in improving safety and capacity means this trend will probably continue. This paper presents a survey of the development of roundabouts in Norway. Design criteria are also discussed and examples of layouts given. Particular attention has been paid to the problems of where to build roundabouts, and where not to build them. The paper also deals with roundabouts in tunnels. In addition to this, the results of a recent study of accident rates are also presented. The study, as earlier studies, shows that small roundabouts normally have the lowest accident rate of all types of one-level junctions. The number of accidents involving pedestrians is remarkably low, but there is a tendency towards problems for two-wheeled vehicles.
Abstract