Standard 2-lane conflict points vs single-lane roundabout conflict points
Studies by the Insurance Institute for Highway Safety show that roundabouts provide a:
- 90 percent reduction in fatal crashes;
- 76 percent reduction in injury crashes;
- 30 to 40 percent reduction in pedestrian crashes; and
- 10 percent reduction in bicycle crashes
A standard stop sign or traffic signal controlled intersection always has at least one direction of traffic stopped. A roundabout uses yield-at-entry traffic control to eliminate stopping when it is not required.
Modern roundabouts are usually less expensive than signalized intersections for two primary reasons:
- Expensive traffic signal equipment, as well as maintenance of that equipment, is not needed; and
- Under certain traffic conditions, the free flow movement of the roundabout is able to reduce the capacity needs of adjoining roadways; thus, fewer traffic lanes may be needed. Roundabouts usually do not require separate left- and right-turn lanes, which also helps lower costs of intersection approaches.
Do not stop within a roundabout. If emergency vehicles are approaching, exit the roundabout before pulling over. If a confused driver stops within a roundabout, do not pass or overtake the driver using the truck apron. Stopping within a roundabout to let another drive in is dangerous and should not be done. It creates an unpredictable situation for drivers around you and can lead to crashes.
Do not change lanes within the roundabout. This is unpredictable behavior to other drivers and can cause crashes. Roundabouts are equipped with signage and pavement markings prior to entry that indicate what lanes will convey you to which exit. In general, Multi-lane roundabouts should be approached the same way as any other intersection. To turn left, use the left-most lane and signal for a left turn. To turn right, use the right-most lane and signal for a right turn. In all situations, vehicle operators should pass counterclockwise around the central island. When preparing to exit, vehicle operators should turn on their right turn signals as soon as they pass the exit before the one that will be used.
Trucks, buses, and other large vehicles may utilize the truck apron surrounding the center of the roundabout in order to safely pass through the intersection. The truck apron is typically a slightly raised area of pavement that is designated by a different color or texture of pavement. Give large vehicles more space to navigate the roundabout, just like you give them more space to turn at intersections.