the periodic needs studies were not without their influence, however, is seen in the provision in section 148 of the 1973 Act that called upon the States to designate three Federal-aid systems. The first was to be the Federal-Aid Primary System, including extensions into and through urban areas. The second was to be the Federal-Aid Secondary System, now to be confined to rural areas. And the third was to be the Federal-Aid Urban System in all urbanized areas and in smaller urban areas that the State highway department might want to designate. The systems were to be designated on the basis of their functional use as anticipated in 1980, which necessitated perceptive planning of routes by function in areas yet to be urbanized or developed in other ways. All the system designations were to be effective after June 30, 1976.
In a requirement for earlier action, another section of the 1973 Act called for the designation of “Priority Primary Routes.“ These routes were to be high traffic sections to supplement the Interstate System by ”. . . furnishing needed adequate traffic collector and distributor facilities . . .“ These routes were to be selected by the State highway departments in “consultation” (not cooperation) with appropriate local officials. The States were to make an initial selection of such routes and estimate and report to Congress by July 1974 their cost. Without specific mileage limitation, this provision was as open-ended as the initial authorization of the Federal-Aid Secondary System. But funds increasing from $100 million in 1974 to $300 in 1976 were authorized.
Perhaps the most significant policy statement of this or other recent acts was the “Declaration of Policy” under section 107. This section declared that “. . . since the Interstate System is now in the final phase of completion it shall be the national policy that increased emphasis be placed on construction and reconstruction of the other Federal-aid systems . . . in order to bring all of the Federal-aid systems up to standards and to increase the safety of these systems to the maximum extent.” This policy declaration presumably would curtail, and hopefully end, the bit-by-bit extensions of the Interstate System. The Interstate System upon its completion, delayed and in some areas curtailed as it was, will be fulfilling admirably, even beyond expectations as to its traffic services and economic benefits, the concept laid down by Congress in 1944. It was in anticipation of this that AASHO and Public Roads began the post-Interstate studies in 1964, studies that reached fruition, at least in part, by this provision nearly a decade later.
Statewide Highway Planning
At State level following passage of the Federal-Aid Highway Act of 1956, planning efforts began rapid expansion. The planning entailed in the early stages of the Interstate program, particularly in the urban areas, a greatly enlarged scope of responsibility—in addition to the amount of work involved, its broadened planning to encompass financial and economic areas and increasingly, the consideration of social and environmental aspects of the highway programs. Fortunately, because planning funds available were a fixed percentage of the apportionments, the increased amounts apportioned for construction under the 1956 Act meant substantial increases in planning funds. Certainly no other general planning or transportation planning program ever was so strongly funded in relation to current planning needs. Even though in the early years of the post-1956 period funds quite amply met the needs, as more and more elements were added to the planning responsibility, this relative affluence soon disappeared.
All States accepted as a matter of course the necessity for keeping planning data current, and many utilized the facts collected in response to studies called for by Congress as a basis for developing statewide plans and programs embracing all road systems. Many reviewed their system designations, and some repeated their earlier statewide needs studies. More attention was paid to long-range programing and efforts were made to provide analytical bases for project annual improvement needs for the 10- and 20-year program periods.
Many States adopted the “sufficiency rating” approach, which rated each road section on the basis of its traffic capacity, structural adequacy, and safety. This approach was based partly on planning data, but more on visual observation of current conditions by an annual inventory. It resulted in a listing of projects on the basis of their current adequacy, or “sufficiency,” as opposed to the longer range “deficiencies,” more commonly reported in the broader needs studies. Knowing the funds to be available for a coming year, a State could develop a construction program simply by going down the list of sections starting with the one currently least sufficient until the available funds were all committed. While this was perhaps not planning, in that it emphasized only current conditions, it was a useful administrative tool because it permitted the highway department to demonstrate to the public that its current program was directed toward correcting the most severe deficiencies, as determined on an objective rating scale. Objections to this approach were that it did not reveal the real future needs, but simply provided an orderly way to distribute currently available funds.
Other States, after the completion of the AASHO Road Test in Illinois, made efforts to adapt to their programing procedures the methods used by the road test staff to determine when a section had been so badly damaged as to justify its being retired from further testing, or in short, failed. The method em-ployed a profilometer or a roughometer to measure periodically the deterioration in riding quality, section by section. These readings did more than provide an objective basis for deciding that a section had failed. It was found in analysis that the trends in current riding quality measurements, called the “present serviceability rating,” could also be used as a reliable prediction of when failure would occur. It offered, in effect, a different approach to the life expectancy of pavements by an analytical rather than by the earlier actuarial approach and section by section rather than simply by pavement types. Some States reasoned that similar trends of serviceability ratings could show when particular sections of routes on their highway systems would need replacement, and saw in that approach a means not only of antici-
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