Unix permissions would be a simple layer to add on top. Create a user/group/root structure for read/write/execute (execute?). A road location would be rwxr--r

Unix permissions would be a simple layer to add on top. Create a user/group/root structure for read/write/execute (execute?). A road location would be rwxr--r-- while a road texture could be rwxrwxrwx. Your player's character look could be rwxr--rwx. A signpost coudl be rwxrwxr--.