It depends -- a road on public land be be either public or private. It depends on what the easement states -- anything thing else you think you know about it is irrelevant. In my case, the easement explicitly states that no public or quasi-public access can be granted and that it is in fact MY private road, which I have to maintain. Other roads may have different restrictions, but that's what mine has. Between easements, attorney fees, surveyor fees, and the building of the actual road I have more that $70k into it, so I think I have enough skin in the game to say with confidence that some roads across public land are in fact private -- at least as far as vehicular access is concerned.