WordNet (r) 3.0 (2006):

motorist
    n 1: someone who drives (or travels in) an automobile [syn:
         motorist, automobilist]

Moby Thesaurus II by Grady Ward, 1.0:

23 Moby Thesaurus words for "motorist":
   Sunday driver, backseat driver, bus driver, busman, cabby,
   cabdriver, chauffeur, driver, hack, hackdriver, hackman, hacky,
   hit-and-run driver, jitney driver, joyrider, operator, road hog,
   speeder, taxidriver, teamster, truck driver, trucker, truckman