In the meantime, check out NPR Fresh Air's interview with Ken Jennings (yes. Ken Jennings the Jepoardy champion) talking about his book Maphead: Charting The Wide, Weird World Of Geography Wonks.
He gives a quick mention about "road geeks" and also mentions Richard Ankrom, the artist who improved one of the I-5 overhead signs a few years back.
Personally, I prefer "Road Scholar" since a lot of what I do involves research.
Anyway, I'll have more to say later.