The National Highway Freight Network (NHFN) defines sections of roadways identified by the Federal Highway Administration (FHWA) as important to the U.S. freight transportation system.  The NHFN includes the following types of roadways:

• Primary Highway Freight System (PHFS): Highways identified as the most critical portions of the U.S. freight transportation system

• Other Interstate portions not on the PHFS (non-PHFS): Portions of Interstate roads not included in the PHFS but provide important continuity and access to freight transportation facilities

• Critical Rural Freight Corridors (CRFCs): Public roads not in an urbanized area that provide access and connection to the PHFS and the Interstate with other important ports, public transportation facilities, or other intermodal freight facilities

• Critical Urban Freight Corridors (CUFCs): Public roads in urbanized areas that provide access and connection to the PHFS and the Interstate with other ports, public transportation facilities, or other intermodal transportation facilities.