The geographic relation of the recommended system to areas of high per-acre value in marketed crop production is shown in figure 9. The general types of principal farm production in areas traversed by the system are shown on the map, figure 10.
Although in comparison with the other systems investigated, the recommended system does not afford so pronounced an advantage in proximity of service to agricultural production as in service to manufacturing industry, figure 11 shows that it does closely approach the greatest service to agriculture obtained by any of the systems. This advantage, as indicated by the spread between the curves of value of agricultural products marketed and of number of counties traversed, reaches a maximum in the 48,300-mile system, but is nearly as great in the recommended system. Nearly all of the advantage accumulated in the 48,300-mile system, however, is contributed by routes which are also included in the recommended system.
Location in relation to situs of motor vehicle ownership.—Cities of 10,000 or more population located directly on the recommended system were the places of ownership in 1941 of 13,932,788 registered motor vehicles. Vehicles registered in the same year by other owners resident in counties traversed by the system numbered 8,180,819. The total of all motor vehicles registered by owners resident in counties traversed by the system amounted, therefore, to 22,113,607. This is 68.7 percent of the total 1941 registration of motor vehicles.
