From the back cover:
Since the publication of the original Car Wars game, autoduellists everywhere have been demanding rules for the big trucks. Well, wait no longer. Here they are.
Truck Stop is a Car Wars supplement; you will need the original Car Wars rules to play. truck Stop gives you movement and ckombat rules for 18-wheelers . . . regular and wreck counters for a variety of big rigs . . . and a map of a typical fortified truck stop in the America of 2033.