Federal-Aid Highway Systems

Federal-Aid Highway Systems:

            In 1912 Congress made the first in a continuing series of appropriations to the states for road construction. This appropriation, followed by annual grants for the years 1916-1920, was for “post roads,” over which the mail was carried. It soon developed that this form of appropriation resulted in scattered improvements without any assurance of continuity or an ultimate system of improved highways. To remedy the situation, federal appropriations since 1920 have been made to limited mileages of roads of specified characteristics; thus the various federal-aid to the use of federal funds. Some but not all of the state, country, and urban road networks are on federal-aid systems.

            Congress has, overtime, redefined the federal-aid system and changed federal-aid allocations with the aim of correcting deficiencies in our road system. It seems clear that in the years ahead, as in the systems described below, the pattern of federal-aid is financing, and permitted uses of funds will be substantially altered.

Federal-Aid Primary or “A” System:

            The federal-Aid Highway Act of 1921 established the federal-aid primary system. It required the states to make an initial selection of 7% or less of their total mileage as a system of primary and interstate highways. Selections were subject to the approval of the secretary of Agriculture operating through an office of public roads. After the 1921 Act, the main trunk roads of the nation, totaling 180,000 mi in length, were quickly selected. This primary federal-aid system often referred to as the “7% system.” Now totals 258,000 mi, including about 34,000 mi in urban areas. When a state has provided for improvement of 75% of its federal-aid primary system, the mileage could be increased by another 1%. In combination with the interstate system, these roads form a dominant part of our rural highway network.

Federal-Aid Secondary or “B” System:

            Congress established the federal-aid secondary system in 1944 to supplement the federal-aid primary system. Its mileage is 96% rural and consists of important country and secondary state highways; in 1970 it totaled 637,000 mi. selection of the routes is the joint responsibility of local authorities, the state highway departments, and the Federal Highway Administration.

Urban Extensions and Urban System (“C” and “D” System):   

            Highways, Streets, and alleys in urban areas total some 560,000 mi. Travel on them (1970) was 51% of the nation’s total. Until World War II, construction and maintenance of streets and alleys were considered to be of local concern, and federal, state and country spending were devoted almost exclusively to rural highways. As traffic in urban areas increased, more and more attention was focused on the problems it created; and federal, state and some times country funds are now used to improve major routes inside the limits of our cities. Federal participation began when congress in 1944 authorized a special fund to aid in extending the rural federal-aid systems into urban areas. In 1970 it created a separate urban system. Routes are to be selected by local officials subject to state and federal approval. Beginning in 1975, some of these funds may be used for mass transit.

National System of Interest and Defense Highways:

            The Interstate system, a selected 43,000 mi of the most important highways in the country, connects and extends into most of our larger cities. Joint selection was authorized by the federal-aid Highway Act of 1944, was approved by the state highway departments and the commissioner of Public Roads, and was finally adopted in August 1947. Included are about 8000 mi of extensions into urban areas and circumferential urban routes. Although it constitutes only 1.2% of all road mileage it is expected to carry more than 20% of all motor vehicle traffic.

            The Interstate system is being improved at the highest standards appropriate for the terrain traversed and the traffic served. Rights of the way are wide to permit roadside improvement, and access is controlled; some 85% of its length is on new locations, since existing developments, poor vertical and horizontal alignments, and other features of the present highways along the same routes cannot be reconciled to the extremely high standards.