Do regular automobile laws apply on the primitive roads?
Yes. And you can even get a ticket from a Ranger if you choose to exceed the posted speed limits on commonly traveled dirt roads. On the really primitive roads though, speed limit signs are not necessary because you couldn’t drive fast even if you wanted to (but who wants to?). Laws regarding accidents and other auto problems apply, and are strictly enforced by the National Park Service. You must carry auto insurance even out here.