Traffic Circle

A traffic circle or rotary is a type of intersection that has a generally circular central island. Entering traffic must typically alter direction and speed to avoid the island, creating a circular flow in one direction. In most applications, traffic circles replace the stop lights and traffic signs that regulate flow in other intersections.

In English-speaking countries other than the United States, circular junctions or intersections are typically in the form of roundabouts which give priority to circulating traffic and which are physically designed to slow traffic entering the junction to improve safety, so that the roads typically approach the junction radially; whereas rotaries are frequently designed to try to increase speeds, and thus have roads that enter the traffic circle tangentially.

In the U.S., traffic engineers use the term roundabout for intersections in which entering traffic must yield to traffic already in the circle, reserving the term traffic circle for those in which entering traffic is controlled by stop signs, traffic signals, or is not formally controlled.