In the western U.S., there are in essence three main categories of tracks open to vehicles: 1) 1. Unsealed roads (gravel or dirt) that are usually open to all vehicles 2) 2. Similar roads that can usually be driven in two wheel drive (2WD) but require high clearance under the vehicle 3) 3. Roads that require the use of four-wheel drive (A fourth that rarely shows up are roads where the bed is sand and you need 4WD but don't need high clearance) There appears to me no way to designate these, and yet the difference is tremendously important. Is there a process for adding '4WD' and 'high-clearance' as tags for tracks? Closest I see is using the surface tag [surface tag](//wiki.openstreetmap.org/wiki/Key:surface) as user-defined, which seems a bit ad hoc. None of the surface or tracktype tags [tracktype tags](//wiki.openstreetmap.org/wiki/Key:tracktype) at present seem appropriate for the kinds of roads I am thinking of.

In the western U.S., there are in essence three main categories of tracks open to vehicles: 1) Unsealed roads (gravel or dirt) that are usually open to all vehicles 2) Similar roads that can usually be driven in two wheel drive (2WD) but require high clearance under the vehicle 3) Roads that require the use of four-wheel drive (A fourth that rarely shows up are roads where the bed is sand and you need 4WD but don't need high clearance) There appears to me no way to designate these, and yet the difference is tremendously important. Is there a process for adding '4WD' and 'high-clearance' as tags for tracks? Closest I see is using the surface tag as user-defined, which seems a bit ad hoc. None of the surface or tracktype tags at present seem appropriate for the kinds of roads I am thinking of.