What is a roundabout?
Modern roundabouts were developed in the United Kingdom in the 1960s and now are widely used in many countries. The modern roundabout is a circular intersection with design features that promote safe and efficient traffic flow. At roundabouts in the United States, vehicles travel counterclockwise around a raised center island, with entering traffic yielding the right-of-way to circulating traffic. In urban settings, entering vehicles negotiate a curve sharp enough to slow speeds to about 15-20 mph; in rural settings, entering vehicles may be held to somewhat higher speeds (30-35 mph). Within the roundabout and as vehicles exit, slow speeds are maintained by the deflection of traffic around the center island and the relatively tight radius of the roundabout and exit lanes. Slow speeds aid in the smooth movement of vehicles into, around, and out of a roundabout. Drivers approaching a roundabout must reduce their speeds, look for potential conflicts with vehicles already in the circle, and be prepared to stop for pedestrians and bicyclists. Once in the roundabout, drivers proceed to the appropriate exit, following the guidance provided by traffic signs and pavement markings.

Show All Answers

1. What is a roundabout?
2. How do roundabouts differ from older traffic circles and rotaries?
3. How do roundabouts affect safety?
4. What are the features of a good roundabout designs?
5. What are the common types of crashes at roundabouts? What can be done to prevent them?
6. How do roundabouts affect traffic flow?
7. Are there other benefits?
8. Can roundabouts accommodate larger vehicles?
9. How do roundabouts affect older drivers?
10. Are roundabouts safe for pedestrians?
11. Do drivers favor roundabouts?
12. What are the impediments to building roundabouts?
13. How common are roundabouts in the United States?
14. Do roundabouts require more space than traditional intersections?
15. What are appropriate locations for roundabouts?
16. What types of intersections may not be good candidates for roundabouts?