Proportional to the fourth power, actually http://www.pavementinteractive.org/equivalent-single-axle-load/ http://www.pavementinteractive.org/equivalent-single

Proportional to the fourth power, actually http://www.pavementinteractive.org/equivalent-single-axle-load/ http://www.pavementinteractive.org/equivalent-single-axle-lo... An 18-wheeler causes 10,000 times the wear of a car, approximately.