George Martin takes the ghost story and brings it into twentieth century America. Europe has ghosts haunting castles, but America doesn't have castles. It has highways. Ghosts in a car is the logical step for hauntings, at least according to Martin.
This is "The Exit to San Breda". Reading it I forgot, at first, that this was to be his ghost story, but I was moved to try to figure out just what was happening and who the ghosts was as a man drives the remants of the American interstate system. America, you see, has gone to personal "copters" and jetpacks and it is only the enthusiasts who still drive cars on the roads which are in various states of disrepair.
This is the second of Martin's "Filthy Pro" stories and while it is not reflective of his later greatness, "The Exit to San Breda" is a solid professional quality story that holds up decades after it was first written.