National Truck Network (NN)

The National Truck Network, or National Network (NN), is a designation applied to highways that can safely and efficiently accommodate large vehicles, such as tractors with one or two semitrailers.   The Federal Highway Administration (FHWA) has the authority, per 23 CFR 658, to designate interstates and other highways that are frequently used by large vehicles to support interstate commerce.

The Highway Performance Monitoring System (HPMS) federal report is the system of record for the NN.  All roads designated by the FHWA are coded a 1 while any roads designated by a state are coded a 2.