International Design Practices for Roundabouts

Roundabouts are a special form of junction, which has been widely implemented during the last years, since for specific cases they are considered a suitable solution, in terms of safety and capacity, compared to conventional intersection types. Different types of roundabouts exist, and the design of each type follows specific principles, for reaching their design potential and avoiding negative implications. Although the roundabout types are common among several countries, the design principles and guidelines vary. This paper reviews the guidelines of six major countries (i.e., the United Kingdom, France, Germany, the Netherlands, the United States and Australia), which are considered front-runners in the design of roundabouts. For each national guideline, the main goal, the field of application and the estimation of basic roundabout geometric elements are identified. Through the comparison of national guidelines, points of convergence and divergence are identified and discussed. Recognizing these points can be a useful guidance for the development of guidelines for other countries, by identifying and transferring elements that best fit their road conditions.