Key Features of a Roundabout

Central Island: The central island is the raised area in the center of a roundabout around which traffic circulates.

Splitter Island: A splitter island is a raised or painted area on an approach used to separate entering from exiting traffic, deflect and slow entering traffic and provide storage space for pedestrians crossing the road in two stages.

Circulatory Roadway: The circulatory roadway is the curved path used by vehicles to travel in a counter-clockwise fashion around the central island.

Truck Apron: If required on smaller roundabouts to accommodate the wheel tracking of large vehicles, an apron is the mountable portion of the central island adjacent to the circulatory roadway.

Yield Line: A yield line is a pavement marking used to mark the point of entry from an approach into the circulatory roadway and is generally marked along the inscribed circle. Entering vehicles must yield to any circulating traffic coming from the left before crossing this line into the circulatory roadway.

Pedestrian Crossings: The crossing location is set back from the yield line and the splitter island is cut to allow pedestrians, wheelchairs, strollers and bicycles to pass through.

Adapted from: Federal Highway Administration, Roundabouts: An Informational Guide, Report No. FHWA -RD-00-067, June 2000.