High Quality Content by WIKIPEDIA articles! A roundabout is the name for a road junction in which traffic moves in one direction around a central island. The word dates from the early 20th century. Roundabouts are common in many countries around the world. It is similar to traffic circles that are primarily found in the United States, except that in a roundabout entering traffic must always yield to traffic already in the circle, whereas in a traffic circle entering traffic is either controlled by stop signs, traffic signals, or is not formally controlled at all.