ROUNDABOUTS IN FRANCE: DEVELOPMENT, SAFETY, DESIGN, AND CAPACITY

This paper discusses give-way-at-entry roundabouts ("garrefour giratoire") which have been in use since 1972 in U.K., and over a wider range since 1984. Over the past 12 years, roundabouts have been installed at a colossal rate throughout France. The number reached approximately 15,000 by the end of 1996. Three factors have resulted in this development: improved safety; reduced geometric size and corresponding cost reductions; and, aesthetic and visual preferences for roundabouts, including the perception of roundabouts as a community focal point. Safety studies regarding roundabouts have been numerous. This paper presents some of the primary results of before and after comparisons, frequency analyses, and comparisons with other intersections. All are favorable for roundabouts. An overview of two new guidelines soon to be published - one for rural intersections and one for urban intersections - is also included. Both guidelines contain important chapters providing basic rules and design standards. Finally, the paper presents an analysis of the capacity software GIRABASE.