The contents of this paper discuss the results of a study concerningroundabout safety in the Vestfold Region, Norway. The main subjects of studyare as follows: 1) Before and after studies of constructing roundabouts andtheir effect on traffic safety; 2) Accident risk studies for roundaboutsduring the period 1991 to 1995; and 3). Traffic behaviour studies withinselected roundabouts and the study of their geometric design. Several actionsare suggested to improve traffic safety in general and particularly for eachof the 6 roundabouts included in the study of traffic behaviour and geometricdesign.