Information Gallery Annual Average Daily Traffic on the National Highway System, 2012 Bridge Condition by Age Group: 2015 Class I Railroad System Mileage and Ton-miles of Freight: 1960, 1965, 1970-2015 BTS Data, Surveys, and Methods National Transportation Atlas DatabaseAirport SnapshotsRural AirportsPort Performance Freight Statistics Program Annual Report to Congress Summary Statistics Tables National Transportation StatisticsSystem Mileage Within the United States (Updated April 2016)Number of U.S. Airports (Updated January 2016)U.S. Public Road and Street Mileage by Functional System (Updated October 2016)U.S. Oil and Gas Pipeline Mileage (Updated April 2016)More NTS TablesState Transportation StatisticsPublic Road Length, Miles by Functional System: 2013Public Road Length, Miles by Ownership: 2013Toll Roads, Toll Bridges and Tunnels, and Toll Ferry Routes: 2012More STS Tables BTS Publications Infrastructure extent and condition chapter in the Transportation Statistics Annual ReportTechnical Briefing: Investment in Transportation AssetsMore BTS PublicationsBrowse Infrastructure in the National Transportation Library Other Resources Highway Performance Monitoring System (HPMS)National Transit DatabaseNational Bridge Inventory Database2015 Status of the Nation's Highways, Bridges, and Transit: Conditions & PerformanceFederal Railroad Administration Maps - Geographic Information SystemPipeline Mileage and Facilities