It was now clear, however, that by the elimination of certain of the routes added to form the 36,000-mile system, the resulting 33,920-mile system, though smaller in extent, would carry a higher average traffic volume than had been attained in either the 29,300-mile or the 36,000-mile system. The routes eliminated were those connecting the smaller cities and serving the lighter traffic volumes. The average daily traffic volume of the resulting system was found to be 2,660 vehicles, as shown by the upper solid dot. This volume is greater than the traffic indicated even by the highest of the intersections in the graph—that representing a 33,000-mile system.
It is believed, therefore, that the 33,920-mile system, data for which are given in the lower section of table 13, is very close to the desired optimum system. As shown in figure 1, it is the system recommended by the Committee for adoption. Although in mileage the existing rural roads conforming to this system constitute only 0.99 percent of the country’s total of 2,964,677 miles of rural roads, it is estimated that they served in 1941 16.79 percent of the total of 465,753,000 daily vehicle-miles of travel on all rural roads in that year.
Conclusions
Facts presented thus far on the interregional highway system clearly lead to the following conclusions:
1. The system, if it is to attract and serve a reasonably large proportion of the total highway movement, must connect as many of the larger cities of the country as its limited mileage will permit.
2. Whatever other facilities it may provide, the system must incorporate adequate routes leading directly into the larger cities, including at least most of the cities of 10,000 or more population.
3. Especially in the more densely populated sections of the country, the general directness of the routes between larger cities should not be sacrificed for close approach to cities of substantially less than 10,00 population. When these small cities lie conveniently in the path of direct routes, they may be adequately served by a skirting location of the main route. Such a location will generally be in the interest of the preponderant part of the traffic.
The recommended interregional system conforms generally to the principles enunciated in these conclusions.
Its 33,920-mile total extent includes 2,123 miles within the municipal limits of cities of 10,000 or more population. This is approximate] the mileage required to provide direct connection into and through all of these cities joined by the various routes. The mileage reported is measured along existing streets now serving the traffic in the capacity described, just as the reported mileage of rural sections of the routes is measured over existing highways conforming closely to the recommended interregional routes in rural areas. A desirable improvement of the system will alter these mileages both within the larger cities and in rural areas, generally by reduction.
Included also in the proposed total mileage of the recommended system are 2,347 miles within the limits of cities of less than 10,000 population. This also is measured along existing strects now carryin the traffic stream intended to be served by the proposed interregional
