well i live in montana.
so all we have are highway's and backroads. there are i think five different interstates. thats it lol (we're the 4th biggest state so thats pathetice)
and i think you can inform a highway sign when its been adopted while its young, but if it unstable refrain from telling him/her, until they mature and wont kill themselves or do something drastic. i hope you adopted a great highway one of these days