[OSM-talk] [Talk-GB] "Unsurfaced road" and "Byway"?

[Richard Fairhurst]

(moved back to talk from talk-gb)

Nick Whitelegg wrote:

> TBH I'd prefer highway=unsurfaced kept in - I use it extensively. Even
> better though - and this is my own high horse :-) - we really need to sort
> out "highway" for non-roads which at the moment is a mixture of physical
> characteristics (track) and legal rights (bridleway).

I was thinking about this while stuck in a jam on the M42 this morning  
(highway=f**ked).

My (admittedly half-thought-out) conclusion is that our highway tag  
represents the _purpose_ of the way.

This is why we have trunk for inter-urban routes; cycleway for, er,  
cycleways; and so on. This is also why we have a difference between  
unclassified and residential, even in urban areas.

It does not represent one sole physical appearance or classification.  
As it happens, in some countries (e.g. the UK, France) the road  
classification system is intended to indicate the same thing - the  
purpose of the road - so it does make sense to align the two.

(In the UK, for example, green signs are used to direct drivers along  
particular inter-urban roads, offering the best way of getting to all  
parts of the nation. This is what we mean in OSM by highway=trunk. But  
in cases such as Oxford High Street and the A452 through Kenilworth,  
where the classification is thoroughly at odds with the purpose of the  
way, we can diverge from this.)

In general, then, we shouldn't overload other implications onto  
highway tags, because this dilutes the principal purpose of the tag.  
So if you want to flag a distinction between rights of way and  
permissive paths, use an extra tag for that. JOSM and Potlatch presets  
mean that this need entail no extra work (and if you need new presets  
in Potlatch, tell me!).

cheers
Richard