Perhaps I've asked this before, so I apologize if that's the case.
Is your source for these access restrictions inference based on land ownership boundaries? I appreciate you working on this since I think road access data is really valuable for routing and the road network, arguably OSM's core feature. This is a double-edged sword, too, since incorrectly tagged access can have a huge negative effect on routing usefulness. This is something that has impacted me directly as a data consumer in the past.
Anyway, I just want to be sure we aren't incorrectly assuming access. Let me know what you think. And thanks for your contributions!!! :)