In 1985 I could be found hunched over my C-64 trying desperately to win this game. I was a fan of Lord British due to his groundbreaking Ultima series which until the Bard's Tale came out was my number one RPG game for the computer.
In the game you are in the North East part of the U.S. and your car is not only a means for protection and warfare but one of the only ways you can earn a living. You begin the game with no car and must enter the Arena's amateur night where you are lent a 'busted up p.o.s.' to earn enough to buy a vehicle. After securing your own ride you can then earn money by taking on courier missions.
Of course the most fun was taking your vehicle onto the highways of the U.S. and battling raiders and roadside gangs. Because if you survive those battles you can loot/salvage the parts to add to your own vehicle. There is a story, most of it involving important F.B.I. courier missions but I just kept on building up my vehicles and keeping the roads safe.