The first result was a strong reaction against the use of heavy motor trucks. There were large numbers of people who, forgetting that a road is of service only in so far as it accommodates the need for economical transportation, demand that the manufacture and operation of vehicles too heavy for the existing roads be prohibited. As few of the roads were designed to carry motor truck traffic, to have taken this course would have amounted to the throttling of a new development In transportation before it had a chance to demonstrate its utility, and it was rightly opposed with great energy by the manufacturers of motor vehicles. The latter, on the other hand, took a position at the opposite extreme from which they demanded the right to manufacture and sell vehicles of large capacity and heavy weight, without regard to the strength of the roads, on the theory that the greater the capacity of the vehicle the smaller would be the cost of operation per unit of capacity. The slogan was, ‘build the roads to carry loads,’ and this was met by the opposite party with the equally dogmatic demand that the loads should be limited to the capacity of the existing roads.
The issue thus joined, the principals to the controversy—highway officials on the one side and the manufacturers on the other—wisely agreed to submit their differences to the test of mutual discussion; and out of the series of conferences which ensued there came an agreement upon certain fundamental facts and principles which have served as the basis for a harmonious cooperation of the two groups, and which now constitute the foundations of highway improvement policy in all States.[1]
The wartime experience was felt in another way also. It was during this period that an intrepid team drove a truck from Detroit to Washington to demonstrate the value to the military of motor transport. This journey, almost an expedition in those days, represents the birth of a new concept of mobility. It demonstrated the value of a connected system of highways. As much as any other factor, it brought about what is now recognized as the most significant feature of Federal aid to highways, the requirement that funds be expended only on a Federal-aid system recommended by the States and approved by the Secretary of Agriculture, the Department within which the Bureau of Public Roads was then located.
This requirement was set forth in the 1921 Federal Highway Act, and reflected the acceptance of the earlier views as to the essentiality of concentrating highway expenditures on a limited system, then set at 7 percent of the total highway mileage of each State. The Act also recognized another national purpose for Federal aid—to serve possible military needs. While later it came to be accepted that the highway system’s military value lay more in aiding in the movement of the materials and products of war industries than in the movement of strictly military vehicles, this Act inspired the selection, by cooperative action of the Bureau of Public Roads and the War Department, of a system of routes of military importance to be included in the Federal-aid system. This system, ultimately portrayed in the “Pershing Map” (General Pershing accepted the responsibility for this effort) served as the basis for the so-called “strategic network” on which Federal-aid funds were to be concentrated during World War II. Thus, the 1921 Act opened the door to another planning effort—the selection of principal highway systems, statewide and national.
World War I also opened the door to another planning area, economic planning. The “harmonious co-operation” of roadbuilders and truck manufacturers had led to the adoption of a limit of 7½ tons as the capacity of vehicles for future production, a figure deemed fair to both (the user being omitted from consideration, evidently). Again quoting Chief MacDonald:
. . . It was recognized clearly for the first time that the cost of highway transportation is made up of the cost of the highways and the cost of operating the vehicles over the highways, and it was agreed that the common purpose of the public highway officials, vehicle manufacturers and operators should be to reduce the total cost of transportation rather than one or the other of the elemental costs. It could be proved that the number of large-capacity trucks already using some of the highways, principally those radiating from and connecting the larger cities—had already grown to the point where the combined savings in operating cost would more than balance the greater cost of providing highway service for them. As to those highways there could be little doubt of the wisdom and economy of building a type of surface adequate for the heavy truck traffic. Other roads, similarly located with respect to cities, had not yet developed a sufficient amount of the heavy traffic to repay the additional cost of the stronger construction, but it was not difficult to foresee that such a condition would develop in the future. On the majority of the roads however, the development of traffic of sufficient weight to justify the higher types of construction was very remote; and it was apparent that the one-time prevailing condition of uniformity of traffic on all roads had been definitely broken down. Instead, a new and much different condition had arisen under which the main intercity roads were found to be carrying traffic far in excess of the much greater mileage of local roads.
Under the new condition the economic justification for the improvement of the main roads lay to a far greater extent than formerly in the reduction of transportation costs and to a lesser degree in the effect upon the value of property. The main roads had become through traffic arteries, as distinguished from the more numerous local roads which continued to be of value primarily through the service they render in giving access to the land.[2]
From the point of view of highway planning, one other important feature emerged from the war and early postwar experience — the matter of highway finance. Recognition that State highways accommodated most through traffic and that the level of their improvement should be based on total transportation cost gave responsibility for financing the improvement logically to users, to be supported by motor-vehicle license fees and excise taxes and the motor-fuel taxes then beginning to come into more widespread acceptance. Local roads primarily serving farms were considered to be the responsibility of property owners served, with the financing coming primarily from real estate taxes, either on the property served or on the entire community.
The experience gained during the first decade following the 1916 Act pointed the direction highway planning would take. The earliest efforts were in the area of traffic counting. Observations included not only the numbers of vehicles, but their classification (passenger cars and trucks of various sizes) to aid in road design and State of registration to provide some gage of lengths of trips and the proportion of travel that was interstate in character as a measure of the propriety of Federal aid. The findings of these surveys coupled with results of the physical research being undertaken, described in Chapter 4, gave
