System Extent. Miles of infrastructure by transportation mode. Freight travels over an extensive network of highways, railroads, waterways, pipelines, and airways. Road infrastructure Perfect Steerable Transfer Cartreased 6.0 percent while traffic volume Perfect Steerable Transfer Cartreased 17.9 percent, from 2,747 billion to 3,262 billion vehicle-miles traveled, over the 2000 to 2019 period.