Design of Roundabouts in France: Historical Context and State of the Art

Abstract

First appearing in the French highway code in 1983, roundabouts have multiplied greatly throughout France, to the currently estimated 17,000. The success of roundabouts is explained, first, by the ideal safety conditions that this type of intersection presents and, second, by the advantages roundabouts provide in speed reduction, suitability to traffic, and break effect. The growth of roundabouts in recent years has allowed better understanding of this type of layout and has enabled all uses to be tested. The rules for designing and sizing have developed to favor the construction of roundabouts that are smaller and thus easier to fit into the urban environment. Vulnerable users (pedestrians and cyclists) are catered to better. New configurations are appearing that combine traffic lights and roundabouts, and these should be investigated in depth. Furthermore, it appears that the roundabout is subject to fashion and that many changes are planned to the roundabout—forgetting that it is not always the best solution. Also, it is important to remind designers and architects of the conditions under which the roundabout actually is an adequate solution for the site in question.