what is the purpose of a traffic circle
Traffic circle A traffic circle is a type of intersection that directs both turning and through traffic onto a one-way circular roadway, usually built for the purposes of traffic calming or aesthetics.[1] Contrary to a roundabout, where entering traffic always yields to traffic already in the circle and merges in directly, the entrances to traffic circles are three-way intersections either controlled by stop signs, traffic signals, or not formally controlled.[2] Colloquially, however, roundabouts are sometimes referred to as circles.[3]
Diamond lane In the United States and Canada, a diamond lane is a special lane on a street or highway that is reserved for specific types of traffic. These lanes are usually marked with white diamonds or lozenge, hence their name. Diamond lanes are generally the right-most or left-most lane on the road. They are usually implemented to provide ways through traffic congestion, for safety reasons, and to encourage environmentally friendly transportation. A diamond lane may be intended for a specific type of traffic, or for several types. The intended use of a diamond lane is marked by traffic signs. In most areas, violating the rules of a diamond lane is punishable by a fine.