Roundabouts are not your dad’s traffic circles

A roundabout is a type of circular intersection with a central island where traffic flows counter-clockwise. Vehicles entering the roundabout yield to vehicles already circulating, and vehicles operate at low speeds. According the U.S. Federal Highway Administration, roundabouts are often safer, more efficient, less costly and more aesthetically pleasing than conventional intersection designs.¹

Difference between roundabouts and traffic circles

Roundabouts are much smaller than older traffic circles (also known as rotaries) and require vehicles to negotiate a sharper turn to enter, forcing traffic to proceed at a lower speed – usually 15-25 miles per hour. Traffic circles typically allow higher speeds on the approach and within the traffic circle. With roundabouts, the potential for serious crashes is virtually eliminated due to lower speeds and because all vehicles travel in the same direction.²

In the video, Modern Roundabouts: A Safer Choice⁴, published by FHWA, roundabouts are noted as being more efficient, with lower costs and longer life span. The video states, “Traffic can move freely through roundabouts. This makes them more efficient than signalized or stop-controlled intersections.” Furthermore, the video notes that “Reduced vehicle idling means fewer emissions and less wasted fuel.” While initial construction costs can be higher than conventional intersections, roundabouts can often have lower operating and maintenance costs compared to signalized intersections. The Modern Roundabouts video reports that, “Roundabouts have longer service lives than traditional intersections resulting in better economic value over the long time, especially when you factor in the reduction of fatal and injury crashes.”⁵