Idea
I would like to suggest making the paved key for highways (and probably other types of elements) official. Taginfo for paved:
http://taginfo.openstreetmap.org/keys/paved#values
The above shows that the key is already being used, but the Wiki doesn’t describe this key, instead redirecting Key:paved to the article about Key:surface.
Rationale
Currently, the surface key is being used as a way of saying that a given highway is paved or unpaved, but often the value for the surface key is not a generic paved or unpaved, but a specific surface type is given.This is of course very useful for describing the particular surface type a given highway has. However, in some cases, a simple information on just whether a highway is paved or not, would be very useful. One such case would be navigation software – if a user chooses to avoid unpaved roads, the software can check the value of the surface key, but in practice most (all?) of the navigation software only checks for a subset of all the possible values the surface key can have. This leads to incorrect (in terms of what the user expects) navigation when, for example, the surface is set to some value that describes an unpaved road, not recognized by the navigation software – if the software assumes that all highways are paved, unless explicitly stated otherwise (by recognized values of known keys), then, in consequence, it assumes that the road in question is paved.
If the paved key was widely used, then the navigation software would have a simple and clear way of checking whether a given road is paved or not. The default value of the paved key for highways could be yes, so that it would be consistent with the assumption that highways in general are paved.
I don’t mean that we should stop using the paved and unpaved values for the surface key – I’m sure those generic values are useful in some cases. However, using the paved key would be also very useful. Also, the surface=paved could also implicate paved=yes and similarly surface=unpaved could implicate paved=no, so that duplication of the information could be avoided when the generic paved and unpaved values are set for the surface key.
I believe that adding an article for the paved key to the Wiki would encourage people to use this tag, and navigation software makers to implement support for it in their applications.
What do you think about that?