National Network for Conventional Combination Trucks: 2017
This map should not be interpreted as the official National Network and should not be used for truck size and weight enforcement purposes. “Other National Highway System” refers to NHS mileage that is not included on the National Network. Conventional combination trucks are tractors with one semitrailer up to 48 feet in length or with one 28-foot semitrailer and one 29-foot trailer. Conventional combination trucks can be up to 102 inches wide.
U.S. Department of Transportation, Bureau of Transportation Statistics and Federal Highway Administration, Freight Analysis Framework, version 4.5, 2019.