Proposal for sidewalk tagging

This proposal is meant to supersede Proposed_features/Sidewalk, Proposed_features/Footway and Proposed_features/Advanced_footway_and_cycleway.

Why?

We (the Italian community, or at least people on #osm-it@oftc) more or less like the first proposal linked above but don't like the other two: it's an abuse of the "footway" name (remember, what's a "farm" now on OSM? We risk that same thing with the term "footway"), and, especially the third one, is, in our opinion, poorly conceived.

Tagging scheme

To specify that the street has a sidewalk, use

sidewalk=(left|right|both)

Default is

sidewalk=no

If the sidewalk diverges from the street, it should be mapped as a separate way, using highway=footway. If it is physically segregated from the street, i.e. a pedestrian can't go in the middle of the street without jumping :), it should have a "barrier" subtag. See the section below.

If the sidewalk also hosts a cycleway, please also use the appropriate cycleway=*.

Subtags

In the following table, side is one of (left|right|both). When side is both, it's possible to skip :side.

Tag	Applies to	Description
sidewalk:side=(raised\|ground\|lane)		Describes whether the sidewalk is raised above the street level, or is just at the same level (ground), or lies within the roadway and it's only delimited by markings (lane).
sidewalk:side:wheelchair=*		Describes the conditions for wheelchairs. Every value described in `wheelchair=*` is suitable.
sidewalk:side:barrier=*		Describes whether the sidewalk is physically segregated from the street, and how. Unlike the above wheelchair, not every value described in `barrier=` is suitable. Accepted values are: hedge, fence, wall, bollard, block, chain. As you can see, this is a subset of `barrier=`: if you need one of the others, you're tagging a footway, and this proposal is not for you. In addition, some common sense is needed for hedge, fence and wall. If they're large or high enough to make it very difficult to pass them, or to constitute a separate way, than it is a footway.
sidewalk:side:barrier=*		When tagged as a node, this tag means something a barrier transversal to the sidewalk, rather than alongside the street. Every value described as a node barrier in `barrier=*` is suitable.
sidewalk:side:surface=*		Describes the surface of the sidewalk. Every value described in `surface=*` is suitable.
sidewalk:side:width=*		Describes the width of the sidewalk. The unit is meters unless otherwise specified.

Examples

Picture	Tagging	Comment
	`highway=` sidewalk:side=ground sidewalk:side*:barrier=hedge
	`highway=` sidewalk:side*=lane
	`highway=` sidewalk:side=raised sidewalk:side*:barrier=chain

	`highway=` sidewalk:side=raised sidewalk:side*:barrier=fence
	`highway=` sidewalk:side*=ground