The freight network of the United States includes 985,000 miles of Federal-aid highways, 141,000 miles of railroads, 11,000 miles of inland waterways, and 1.6 million miles of pipelines connecting ports, airports, cities, manufacturing centers, farms, mines, and other economic activity. Approximately 200,000 miles of highways are designated for conventional combination vehicles, of which 26,000 miles are major freight corridors. This network is described in the Freight Story 2008.
While freight moves throughout the country, substantial portions of international and interstate commerce are concentrated in major corridors. The reliability of freight movement in these corridors is essential to the nation's economy.
United States Department of Transportation - Federal Highway Administration