ROUNDABOUT SAFETY EXPERIENCE

In 2006 Ourston Roundabouts Canada completed a “Synthesis of North American Roundabout Practice” for TAC. The synthesis consisted of a literature review of roundabout guides and current practice, research and case studies, supplemented with selected experience in other countries where appropriate. It also reported on the results of a web-based survey of public road agencies in Canada and the United States on roundabout planning, design and operating practices. The synthesis found that roundabouts are usually constructed for one or more of three reasons: safety benefits, capacity benefits, or environmental benefits. Currently the main reason for constructing roundabouts in North America is greater intersection safety, as various studies have shown they can reduce injury collisions by about 75% compared to stop control or traffic signals. This paper presents the results of the synthesis as they apply to roundabout safety. It explains why roundabouts have such a high potential for safety. It discusses the studies undertaken in North America (and in other countries where North American data is insufficient) to evaluate the effects of roundabouts on the safety of motorists, pedestrians and bicyclists. Finally, through a discussion of the web-based survey it describes what measures can be taken in the design of roundabouts to maximize their safety potential. These measures may vary depending on whether the roundabouts are single-lane or multi-lane, or whether there are any high-speed approaches.