Dave Dudley's "Six Days on the Road," released in 1963, was the first crossover truck driving hit, reaching number two on the Country chart and 32 on the Pop chart. Country music and truck driving have been associated ever since. "Six Days on the Road" has been covered any times, with the vocalists often (but not always) adopting Dudley's slurred words, especially in the last line of each verse.
[This began as a post on "Six Days on the Road," but I couldn't resist adding some clips of the other country trucking songs below.]
One of the very few video clips of Gram Parsons and Emmy Lou Harris:
Buck Owens's 1965 "Truck Drivin' Man" might have even more covers (yes, I know that both "Six Days on the Road" and "Truck Drivin' Man" were released before Dudley's and Owens's versions, but those two made the songs famous).
I could not find a video clip of Merle Haggard's great song: