I spend lots of time on the road - but somewhat differently than regional sales types.
Every other week (on average) I do 3 day VMS classes at various locations around the US (primarily) - and I hate to fly if I can avoid it.
I live in Raleigh, NC and the average drive time to class locations is at least 5-6 hours, with others (like my class in Orlando next week, and my many N Jersey classes) that are at least 8-9 hours.
So I don't generally drive short distances...
Like Michael above, I like to have lots of choices. This gives me options based on my mood.
Like Ari above, the music I listen to depends largely on how I am feeling at the time.
EDM is always a staple.... I dig the repetitive beats and I have a large collection of EDM that I always travel with. Makes the drive seem like it takes less time.
Classic rock allows me to sing along since I generally know the words, and I have fond memories of Foghat's Slow Ride (full version) blaring on the radio as I flawlessly ripped off the air guitar intro crossing the border from WV into Ohio back in the day...
If my rental car has satellite, I listen to a lot of Howard Stern (Sirius XM - channels 100 and 101).
Variety is the key, imo.