Are you sure? Truck burns 6 miles/ gallon. New EPA regulations in 21 century actually increased fuel consumptions since about 20% of engine's power goes to cleaning the air. Modern car use 30+Miles/gallon.
Road wear isn't linear with weight. Estimates I've seen put a heavy 18-wheeler at the equivalent of more than 9,000 cars traveling over the same stretch of road. Way, way more than 5x the damage (6mpg vs 30mpg).