|Specifies whether a highway is a dual-carriageway (divided) road|
|Used on these elements|
|Tools for this tag|
The tag dual_carriageway=* has been used to specify whether or not a highway is a dual carriageway or divided highway: a road with a dividing strip or barrier between the traffic in opposite directions. The carriageways in each direction may be divided by an open strip, central reservation or median of grass or bare ground, or by a barrier such as a low wall, fence or hedge. Usually there are two or more lanes in each direction. Note that this tag is not used for motorways.
The great majority of uses of this tag are in Krakow, Poland, though it has been used in a handful of other places.
How to map
Usually dual carriageway highways, where each direction of travel is divided by a physical separation or barrier, are mapped with a separate way for each direction of travel, and the tag oneway=yes is added. Position the nodes in alignment (as shown in the example).
- highway=motorway - a motorway or freeway. While almost all motorways are dual carriageway, divided highways, this tag is not used in that case, since it is implied by the tag highway=motorway.
- expressway=* - commonly used in the United States to tag a dual carriageway "divided highway" with high-speed design features and limited access to adjacent properties or partial grade separation.
- motorroad=* - highways that have motorway-like access restrictions. Commonly used in parts of Europe and Japan to specify a road designed for motor vehicle use only.