Put another way, if you double the weight of a vehicle, then the damage it does gets doubled four times. This means that double the weight causes 16 times the damage. Spreading the weight over many wheels and many axles greatly reduces the damage caused per pound of vehicle weight. Also, axles spaced just a few feet apart do less damage than axles located individually when used on asphalt pavement. On concrete pavement, the damage is independent of the axle spacing.
Cars do little or no pavement damage in comparison to large trucks.
It takes approximately 12,000 cars to do the same damage as a single 80,000 pound 18-wheel truck. Engineers who design pavement typically ignore the number of cars and only concern themselves about the number of trucks. Argonne National Laboratory, Division of Educational Programs, Harold Myron, Ph.D., Division Director.