U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
Highway Statistics 2009
Percentage Distribution of Traffic Volumes and Loadings on the Interstate System 1/
1/ Based on data from the Truck Weight Study which are collected by the States for varying time periods each year and are not adjusted to typify annual averages. Loadings are based on equivalent axle loads which are the damage to a pavement caused by a vehicle axle relative to an 80 kN (18,000 lb) force which represents a standard single axle.