[Tagging] Formalising shoulder tagging

[Richard Fairhurst]

Hi all,

At present there is no documented standard for tagging highway shoulders.

We have http://wiki.openstreetmap.org/wiki/Shoulder with 
shoulder=yes|no, which has been in 'draft (under way)' since 2010. In 
Australia, cycleway=shoulder appears also to be used.

Taginfo stats are:
	shoulder = *			7120, of which:
		shoulder = no		3230
		shoulder = yes		2743
		shoulder = right	964
	shoulder:width = *		1794
	shoulder:right = *		1047
	width:shoulder = *		843
	cycleway = shoulder	502

There are several gazillion miles (approximate value) of roads with 
shoulders around the world. We should have a way to tag them.

I'd therefore suggest simply formalising the most popular existing usage 
and the one on the wiki page - that is, shoulder=yes|no. As a default, 
I'd suggest shoulder=yes is presumed as the most common real-world 
situation, i.e.:

	"A paved shoulder, wide enough to be used as an emergency
	 refuge for cars, and for through passage by bicycles."

(Narrow shoulders can of course be tagged with shoulder:width, gravel 
ones by shoulder:surface, and so on.)

There are of course many refinements one could imagine, for peak-hour 
shoulder running, buses, etc. But since "the perfect is the enemy of the 
good" etc., I'd like to get the basic shoulder=yes|no agreed first.

Speak now or forever hold your peace!

cheers
Richard