[Tagging] "width" on streets: Time for a recommendation

Mark Wagner mark+osm at carnildo.com
Tue Sep 15 19:38:04 UTC 2020

On Tue, 15 Sep 2020 10:09:17 +0200
Martin Koppenhoefer <dieterdreist at gmail.com> wrote:

> on unpaved
> roads, measure the extent of the maximum width that vehicles actually
> use, on a medium to narrow part of the highway (i.e. do not add the
> smallest width to a long stretch of highway if it only occurs for a
> short part, rather split the highway in this case of tag the narrow
> exceptions explicitly while using a medium value for longer
> stretches).

In my experience, unpaved roads don't have a well-defined width.
Typically, you've got the following options, roughly from widest to

1) Obstacle-free width: the distance that's clear of fences, trees,
ditches, brush, boulders, and other obstacles.  Not well-defined for
roads in farm country, which may be obstacle-free all the way
to the next road, and misleading in ranch country, where the nearest
obstacle is usually the fence marking the edge of the right-of-way.

2) Vegetation-free width: the distance clear of any vegetation.
Usually the easiest to spot and measure, but may include things such as
spoil from road maintenance which are unsuitable for driving on.

3) Maintained width: the distance that's kept smooth, level, and firm
through regular maintenance.  This is probably the closest to the
"curb-to-curb" or "edge-to-edge" width of a paved road.  This has the
problem that it can change from year to year as graders take different
routes eg. around curves, and is difficult to tell apart from the
vegetation-free width. It also has the problem that many roads are not
maintained except for removal of fallen trees and other obstacles.

4) Driven path: the portion of the road regularly used by drivers.
Unpaved roads frequently develop a well-defined set of ruts that are
easy to measure.  However, this width varies rapidly with road

Which one is "the" width of the road?

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