STATUS OF IMPROVEMENT OF THE INTERSTATE HIGHWAY SYSTEM AND ITS SERVICE TO TRAFFIC
Extent of the System
The existing roads and streets presently serving as routes of the National System of Interstate Highways, shown in figure 1, have a total length of 37,800 miles. Of this total, 3,778 miles are composed of streets in “urban areas” including all cities of 5,000 or more population by the 1940 census, and 2,191 miles consist of streets in towns of less than 5,000 population. The total included mileage of streets in urban places is, therefore, 5,969 miles. The remainder of the system as presently designated consists of 31,831 miles of rural roads located outside of the limits of all towns and urban areas.
MILEAGE AND TRAFFIC
The 5,969 miles of urban streets included in the system represent about 2 percent of the 316,536-mile total length of all city streets. The 31,831 miles of the system’s rural-road sections represent 1 percent of the country’s total of 3,009,617 miles of rural roads.
In 1948, the 5,969 miles of urban streets included in the system served an estimated 20,740 million vehicle-miles of travel. This traffic, served by 2 percent of the total city-street mileage, was almost 11 percent of the traffic served by all city streets.
The 31,831 miles of rural roads included in the system served during 1948 an estimated 33,965 million vehicle-miles of travel. This traffic, served by 1 percent of the total rural-road mileage, was 17 percent of the traffic served by all rural roads.
The existing streets, constituting the urban sections of the system, carried in 1948 an average traffic of 9,500 vehicles daily. This compares with an average for all other city streets of about 1,600 vehicles per day.
Existing roads constituting the designated rural sections of the system carried in 1948 an average traffic of 2,915 vehicles daily. This compares with an average of about 1,295 for the entire Federal-aid primary highway system, 1,155 for the State highway systems (exclusive of local roads under State control), and 53 vehicles per day for all rural roads not included in any of these systems.
The 1 percent of the country’s total rural-road mileage, which forms the rural portion of the designated interstate system, served in the several States an average of 2714 percent of the travel on all rural roads in each State by vehicles registered in other States. The designated rural system is thus shown to be outstandingly of service to that portion of the country’s highway traffic that can be classed as interstate in character.
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