A while ago, I mapped and tagged a few of the access/service roads
behind houses in north Birmingham (locally, we call them gullies).
You can see them on:
http://www.openstreetmap.org/#map=15/52.5403/-1.9234
as, for example, brown/pink dashed lines south-east of Booth Farm
Road; and white
I've wondered about these in the past too. I'm not quite sure that track
is correct even though they are unpaved (to me a track is more rural). How
about:
highway=service
service=alley
surface=unpaved
I guess the next question is - what if the alleyway is only wide enough for
wheelie
The main thing is that they are marked as private access if they are gated.
This way we ensure that the routing engines do not try and use these as
short cuts. If not gated, I would be tempted to mark as unpaved assuming
part or all of the alley is indeed unpaved (I wouldn't worry too much about