Are motorcars allowed on 'track' roads ?

The defaults depend on the country. E.g. in Germany it is allowed but in Austria not. I would try it by bike first or avoid it :)

In England off-road Rights of Way are one of three classifications and tracks may fall into one of these descriptions as well.

1.Footpaths allow walkers only 2. Bridleways allow walkers, horse riders and cyclists, the latter are supposed to give way to walkers and horses 3. Byways allow motor vehicles ( but in winter months they may be closed to avoid the surface being churned up too much) they may have sign and, or barrier to show this, but they do still function as a Bridleway even when closed...usually. The local county council web site and their main office will have a map of rights of way called the "Definitive Map" for anyone to look at and check, this is a good place to verify rights of way. BUT because this map is based on Ordnance Survey Data they are copyright holders. We must not draw a map from them. We have to use a gpx trace or Bing. The restrictions and cost of use, of our, originally government owned, national mapping (OS) ( that we paid for through taxes) prompted Steve Coast who invented openstreetmap and why i and lots of others started to contribute all those years ago so everyone can have a map for free. When i told others what i was doing they had their doubts, but wikipedia works and so does openstreetmap.

imho trackgrades 1,2 and 3 are suitable for motorcars 4 and 5 not.

ok, this is not an absoluter rule but i think it's a good semplification. anyway the a track should be the last choice for the routing algorithm.

bye

That a thoroughfare is a track does not say one way or the other whether motor vehicles are allowed or not. In addition, some people take the motorcar= tag to mean "can the track physically accommodate a motor vehicle ?" as opposed to "are motor vehicles allowed ?"

Also, some people take the "motorcar=yes" tag to mean "there is no motor vehicle prohibition" whereas others take the "motorcar=yes" tag to me "motor vehicles have been positively been verified as being allowed".

Also, the track may be over private property (or a segment of it might be), in which case you will have to contact the land-owner; they may say yes or no or maybe. Remember that the landowner can change their mind faster than OSM can be updated.

Not very helpful, I know. Best do what the other says: plan a route which assumes that you can't, and change to using the route if the possibility arises.

Tracks are wide enough to accomodate a four-wheeled vehicle but since tracks do not usually possess a hard surface, not every car might be suitable. Also, if there are no further tags, there might be a sign prohibiting motor traffic. The answer to your question is, if you can plan your route to pass by the shortcut, and then decide what to do when you're there - do that. If you want a safe route with as little nasty surprises as possible, then don't use the track; it might well out to be private, or forestry use only, or something like that. Keep in mind that it may have been mapped by a pedestrian or cyclist who was not interested in evaluating whether or not motorized traffic is allowed.