Priority within the circulatory roadway

For multilane roundabouts, the issue of priority within the circulatory roadway is important. Any vehicle on the inner track on the circulatory roadway (e.g., a vehicle making a left turn) will ultimately cross the outer track of the circulatory roadway to exit. This may cause conflicts with other vehicles in the circulatory roadway.

Consistent with its lack of treatment of roundabouts, the UVC does not provide clear guidance on priority within the circulatory roadway of a roundabout. In general, the UVC provides that all overtaking should take place on the left (UVC §11-303). However, the UVC also specifies the following with respect to passing on the right (UVC §11-304a):

The driver of a vehicle may overtake and pass upon the right of another vehicle only under the following conditions.

1. When the vehicle overtaken is making or about to make a left turn;
2. Upon a roadway with unobstructed pavement of sufficient width for two or more lines of vehicles moving lawfully in the direction being traveled by the overtaking vehicle.

A case could be made that this provision applies to conditions within a circulatory roadway of a multilane roundabout. Under the definition of a roundabout as a single intersection, a vehicle making a left turn could be overtaken on the right, even though the completion of the left turn requires exiting on the right.

International rules of the road vary considerably on this point. The United Kingdom, for example, requires drivers to “watch out for traffic crossing in front of you on the roundabout, especially vehicles intending to leave by the next exit. Show them consideration.” (9, §125) This is generally interpreted as meaning that a vehicle at the front of a bunch of vehicles within the circulatory roadway has the right-of-way, regardless of the track it is on, and following vehicles on any track must yield to the front vehicle as it exits. Australia, on the other hand, does not have a similar statement in its legal codes, and this was one of the factors that led Australians to favor striping of the circulatory roadway in recent years. Further research and legal exploration need to be performed to determine the effect of this legal interpretation on driver behavior and the safety and operation of multilane roundabouts.

For clarity, this guide makes the following recommendations:

• Overtaking within the circulatory roadway should be prohibited.
• Exiting vehicles should be given priority over circulating vehicles, provided that the exiting vehicle is in front of the circulating vehicle.