|The width of a feature|
|Used on these elements|
|Status: de facto|
|Tools for this tag|
The key width describes the actual width of a way or other feature. By default, values will be interpreted as metres. To reduce the risk of misunderstandings, or if the width should be specified in a different unit, the unit can be added to the end of the value, separated by a space (see #Examples). The value should always use the dot as decimal separator, if needed.
The source of the width information can be specified by source:width=*.
|Two metres||width=2||Alternatively width=2 m could be used. But this is far less common.|
|0.6 miles||width=0.6 mi||Please note the dot as decimal separator!|
|16 feet and 3 inches||width=16'3"||Use a typewriter apostrophe character after the feet value and a typewriter double-quote character after the inches value. Spaces are not permitted.|
Legally restricted width
Do not confuse the specification of the actual width with the specification (of a legal restriction) of a maximum permissible width of vehicles via maxwidth=*.
It is discouraged to specify values as, e.g.,
width=narrow or similar. See therefore this proposal.
If the width couldn't be exactly determined or is estimated, use the key est_width=* instead.
Often the values themselves are not specified correct. The following table contains examples of incorrect tags and their correct notation.
||The space between value and unit is missing.||width=2 km|
||The comma is used as wrong decimal separator.||width=0.6|
||There should not be a space between feet and inches.||width=12'6"|
Width of streets
It is controversial how to define the width of roads if the road includes elements such as sidewalks or parking lanes. Some mappers define width from curb to curb (including parking lanes if they are on street), others define the effective width of the carriageway or even the whole cross-section including side paths.
To avoid these ambiguities, some tags are in use to specify the width of different elements:
- width:carriageway=* for the width of the entire carriageway (from curb to curb or edge to edge, including parking lanes if they are on street),
- cycleway:<side>:width or sidewalk:<side>:width for the width of cycle paths or sidewalks (or simply "width" for their effective width if they are mapped separately),
- parking:lane:<side>:width for the width of parking lanes,
- shoulder:width for the width of shoulders,
- width:lanes for the width of different lanes.
The effective usable width of the carriageway (the width of the area on which vehicles move in flowing traffic) can be determined either from width:carriageway=* minus any existing parking lanes (see the parking:lane=* scheme) or from the use of width:lanes. width:effective=* is rarely used to specify this. However, with or without markings, relocated vehicles, etc. it is unclear where the exact limit for measuring the effective width is located.
Consider using est_width=* if you can only estimate the width.
See https://lists.openstreetmap.org/pipermail/tagging/2020-September/thread.html#55362 for discussion on mailing list how this tag should be defined for roads.