The National Network (or National Truck Network) is a network of approved state highways and interstates for commercial truck drivers in the United States. The Surface Transportation Assistance Act of 1982 authorized the establishment of a national network of highways designated for use by large trucks. On these highways, Federal width and length limits apply. The National Network (NN) includes almost all of the Interstate Highway System and other, specified non-Interstate highways. The network comprises more than 200,000 miles (320,000 km) of highways.[1]