Systems for Route Designation

Systems for Route Designation:

            Practically all the major highways in the United States are marked with route-designation signs for the convenience of the motoring public. This route-designation system is separate and distinct from that used for highway management purposes, and the two should not be confused. Briefly, the route-designation plans are as follows:

Interstate Routes:

            A numbering system, consistent nationwide, developed by the American Association of the State Highway Officials (AASHO). Signs are reflectorized and in full colors-red, white, and blue.

United States Highway Routes:

            A numbering system, reasonably consistent nationwide, that overlaps portions of the federal-aid and state highway systems. East and West trending routes are even-numbered, with the lowest numbers in the north; north and south trending routes are odd-numbered, with the lowest numbers to the east. The sign shape resembles a shield.

State Highway Routes:

            A numbering system for routes of some continuity within individual states. Each state has adopted a distinctive shape or pattern for its sign; for example, the Pennsylvania route marker resembles a keystone. Similar numbering schemes also have been developed by some local agencies.

Special Designations:

            At times, freeways or toll roads are given special designations to identify them more clearly in the minds of motorists. Examples are the Henry Hudson Parkway in New York, the Will Rogers Turnpike in Oklahoma, and the San Bernardino Freeway near Los Angeles. Research is underway to develop far more sophisticated motorist advisory systems. These are discussed in Chapt. 10.