Truck drivers regularly relied on one another to watch for such "smokeys" so they could circumvent the still widely unpopular National Maximum Speed Law, which limited all drivers to 55 miles per hour (89 km/h), so they could cover more distance in a given time than the law allowed.
Unfortunately for the song's hero, The White Knight is an undercover member of the Georgia State Patrol who uses the CB radio to pretend to be a trucker himself to lure rig drivers into a speed trap.
After driving for some time at high speed and listening to country music on the radio, he hears a driver going the other way warning him of a patrol car equipped with radar ahead.
The Mean Machine dutifully slows down to the speed limit until he is past the patrol car (whom he mocks by calling him "Super Trooper" and noting "there's that crazy Smokey over there with a CB of his very own.").
As he goes ever faster, the Mean Machine is soon surprised to see a patrol car's lights in his mirrors, and he is dismayed to learn that the "Super Trooper" patrolman and the White Knight are one and the same.