Enhancing Intersection Safety Through Roundabouts: A Proposed ITE Informational Report

The modern roundabout is a type of circular intersection that requires drivers to yield to traffic in the circle when entering and allows for continuous traffic flow at low speeds. Roundabouts are used throughout Europe and Australia to manage traffic at busy intersections, and are increasingly being used in the United States. When properly designed, roundabouts can provide substantial safety benefits compared with traditional intersections. Where roundabouts have been installed in the United States, motor vehicle crashes have declined by about 40 percent, and those involving injuries have been reduced by about 80 percent. Studies of intersections in Europe and Australia converted to roundabouts have reported reductions in injury crashes of 41 to 61 percent, and reductions in severe injury crashes of 45 to 75 percent. Crash reductions are accompanied by significant improvements in traffic flow, thus reducing vehicle delays, air pollution, and fuel consumption. Several features of roundabouts promote safety. At traditional intersections with stop signs or traffic signals, some of the most common types of crashes are right-angle, left-turn, and head-on collisions. These types of collisions can be severe because vehicles may be traveling through the intersection at high speeds. With roundabouts, these types of potentially serious crashes are virtually eliminated because vehicles travel in the same direction. Installing roundabouts in place of traffic signals also can reduce the likelihood of rear-end crashes and their severity by removing the incentive for drivers to speed up as they approach green lights and by reducing abrupt stops at red lights. The vehicle-to-vehicle conflicts that occur at roundabouts generally involve a vehicle merging into the circular roadway, with both vehicles traveling at low speeds (15-20 mph). To help synthesize and disseminate available information regarding safety aspects of roundabout design and operation, the ITE Transportation Safety Council is developing an informational report entitled Enhancing Intersection Safety Through Roundabouts. The report will identify safety benefits of modern roundabouts, as well as specific design practices and features that enhance safety at roundabouts. This paper lists the thirteen chapters in the proposed report.