The cop who was standing on that same road with him and the State Police lady (who he told exactly where he was, exit sush and such on highway whatever) who was supposed to be passing along info.
So OK lets just say Shep was too stupid to figure it out. THEN WHY IN GOD'S NAME DIDN'T THE COP OR THE SATE POLICE LADY TELL HIM? I mean if it was sooooooo damned obvious shouldn't those folks be able to help him out?
I don't know. Maybe they hoped he would just die. Maybe they simply could not believe he was asking a question with such a "damned obvious" answer. And let's just say they gave him a mapquest quality answer guiding him to rescue Nirvana. Since they don't have electricity within several hundred miles of Shep's satellite van, do you really think anyone roaming the streets of New Orleans would have heard the answer? The bottomline is, there is just no helping some people.