Carriageway

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Diagram showing different arrangements of the elements of a road

A carriageway[1] (North American English: roadway,[2] informally direction, side and lanes, improperly the singular lane[3]) 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 single carriageway road (North American English: undivided highway) has one carriageway with 1, 2 or more lanes together with any associated footways (North American English: sidewalk) and road verges (North American English: tree belt). A dual carriageway road (North American English: divided highway) has two roadways separated by a central reservation (North American English: median). A local-express lane system (also called collector-express or collector-distributor) has more than two roadways, typically two sets of 'local lanes' or 'collector lanes' and also two sets of 'express lanes'. "Cars only" lanes may be physically separated from those open to mixed traffic including trucks and buses. Roughly the northern half of the New Jersey turnpike in the United States, from Jamesburg to its northern limit in Secaucus, is an example of this design. High-occupancy vehicle lanes may also be physically separated from the remainder of the general traffic lanes as a distinct roadway. Some cities such as Pittsburgh, Pennsylvania, have many buses-only roadways to alleviate congestion related to public transit buses, despite its very challenging topography which severely limits the extent to which arterial roadways can be added or augmented.

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References[edit]

  1. ^ "Multi-lane carriageways (133-143)". Highway Code. "A dual carriageway is a road which has a central reservation to separate the carriageways." 
  2. ^ "Railroad-Highway Grade Crossing Handbook - Revised Second Edition August 2007 - Glossary". Federal Highway Administration. "The portion of a highway, including shoulders, for vehicular use. A divided highway has two or more roadways." 
  3. ^ "alt.usage.english "Both lanes of the six-lane expressway"". Retrieved October 22, 2011.