A carriageway (British English)[1] or roadway (North American English)[2] consists of a width of road on which a vehicle is not restricted by any physical barriers or separation to move laterally. A carriageway generally consists of a number of traffic lanes together with any associated shoulder, but may be a sole lane in width (for example, a highway offramp).
A dual carriageway is a road which has a central reservation to separate the carriageways.
The portion of a highway, including shoulders, for vehicular use. A divided highway has two or more roadways.