§658.9 National Network Criteria The National Network listed in the appendix to this part is available for use by commercial motor vehicles of the dimensions and configurations described in §658.13 and §658.15. For those States with detailed lists of individual routes in the appendix, the routes have been designated on the basis of their general adherence to the following criteria. • The route is a geometrically typical component of the Federal-Aid Primary System, serving to link principal cities and densely developed portions of the States. • The route is a high volume route utilized extensively by large vehicles for interstate commerce. • The route does not have any restrictions precluding use by conventional combination vehicles. • The route has adequate geometrics to support safe operations, considering sight distance, severity and length of
grades, pavement width, horizontal
curvature,
shoulder width,
bridge clearances and load limits, traffic volumes and vehicle mix, and intersection geometry. • The route consists of
lanes designed to be a width of or more or is otherwise consistent with highway safety. • The route does not have any unusual characteristics causing current or anticipated safety problems. The National Network was most
recently defined by the
Intermodal Surface Transportation Efficiency Act of 1991. Information on these routes are taken from
§658 Appendix A. Some states such as
Indiana,
Arkansas, and
Ohio allow truck traffic on all
numbered state or U.S. highways. Other states, such as
New York and
California, have a specially defined set of highways which are recommended for trucks. The law allows for "reasonable access" to and from the NN for terminals, deliveries, trucks stops, repairs, and other reasons. The NN is recommended for
through truck traffic (e.g. traffic that is passing through the area), and trucks are allowed to operate on truck-restricted roads if they have no other means of access to their destination. ==See also==