Page:Needs of the Highway Systems, 1955–84.pdf/5

 NEEDS OF THE HIGHWAY SYSTEMS, 1955—84

The cost of needed construction, designed to modernize the Nation’s roads and streets over the next 10 years, will amount to $101 billion, and an additional $25 billion will be required for highway maintenance and administration.

These are the estimates obtained in a study undertaken in 1954 by the Bureau of Public Roads, with the cooperation of the State highway departments, in accordance with the request of Congress for


 * * * a study of the costs of completing the several systems of highways several in the States * * *

INTERPRETATIONS The intent of the request by the Congress is clear, but the interpretation of the specific wording warrants some discussion.

Continuing needs

It is not possible to “complete” a highway in the sense that it can by a single construction, operation be made forever adequate. From the very day that highway facilities are opened to traffic, they begin the course of deterioration and obsolescence that eventually leads to necessary reconstruction or replacement.

Natural forces—heat, cold, and moisture—subject the roads to damaging erosion, freezing and thawing, contraction and expansion.

The endlessly repetitive passage of vehicles, particularly those with heavy axle loads, pound away, flexing and fatiguing the surfaces.

The volume of traffic is ever increasing; there is continuous change in the characteristics of the vehicles—their sizes, weights, power, and speed capabilities; new traffic needs develop. Thus in time it becomes necessary to straighten alinements, reduce grades, provide more width, and add new roads.

Individually and in combination these forces operate to make the highways a continuous job of building, improving, and rebuilding process. In this sense, therefore, a highway system is never complete.

Basis of needs

The term “needs” likewise requires explanation. It is a word widely used in recent years to denote construction backlog. Amounts cited as “needs” sometimes refer to the cost of complete modernization as of a given moment; sometimes they cover a construction program stretching over a period of years.

Some estimates are based on the needs of current traffic; others take future traffic fully into account.

There are variations, too, in the specifications of design standards, and there are differences in their application—one study may permit no deviations, while another will accept large deviations or tolerances. 1