Roundabouts for safer roads

This paper describes guidelines and research results about the design of roundabouts and their effects on traffic safety.After an introduction, the principal geometric elements of a roundabout are discussed in relation to traffic safety.Attention is given to specific accommodation for cyclists and pedestrians.Next, international research results concerning roundabouts and effects on traffic safety are discussed.Some methodological aspects as well as conclusions from research are dealt with.It is explained why roundabouts have positive effects on traffic safety.Finally, the research results are described, as well as the global effects of roundabouts on traffic safety and specific results for bicyclists and pedestrians.Some case studies, and particular roundabout designs, such as the "turboroundabout" or the oval-roundabout, are treated and the relationship between design elements and traffic safety was explored, together with conclusions and suggestions.