There's a good write-up about about road classification from a local mapper here: https://www.openstreetmap.org/user/willkmis/diary/399345

It might also be a good place for a discussion about odd mixed-use developments like this one. I always meant to get back to this and clean up some of the quick'n'dirty editing I did previously (just to get it more or less usable by routers)... maybe I'll do that now. I have no idea what I was thinking with those layer=-1 tags, probably editing as I was falling asleep. :D
 