Because, roundabouts are much safer than ordinary crossroads, more than 2000 complete roundabouts were constructed in the Netherlands in the past 20 years. However, the priority rule for cyclists on separate (protected) cycle tracks on the outside of individual urban roundabouts is still subject to discussion: should cyclists have priority or not? This report shows the safety effects of both priority rules. To do this, the report made an estimate of the number of urban roundabouts with separate cycle tracks, and the registered number of casualties on these roundabouts of crashes between motor vehicles and cyclists, mopedists, or slopedists (light-mopeds are also known as slopeds). The report shows what would have happened if the priority rule on all urban roundabouts with a separate cycle track had been the same: either all cyclists 'with priority' or all 'without priority'. In the case of all 'cyclists without priority', the number of in-patients would be 59-84 a year less (-87%) than on ordinary crossroads. In the case of all 'cyclists with priority', the number of in-patients would only be 7-11 a year less (-11%) than on ordinary crossroads. The difference between the general use of either one or the other priority rules is 52-73 in-patients a year. This is the 'extra' number of casualties in the case of 'with priority'. These numbers are 1.8% and 2.5% respectively of the total annual number of in-patients among cyclists, mopedists, and slopedists that collide with motor vehicles.