pays wholly or in large part through special user taxes; and, increasing in future years, would ultimately force the substantial rebuilding which on many sections of these highways is already urgently necessary.
The needed rebuilding and improvement of the main rural highways is only one element in the larger program of work required for the adequate modernization and extension of the public street and highway facilities of the country which is described in the following pages.
TRANS-CITY CONNECTIONS AND EXPRESS HIGHWAYS
One of the striking characteristics common to all highway traffic maps (see pl. 8) is the sharp enlargement of the bands representing the volume of traffic on the important highways as they approach the larger cities. Obviously these enlargements have a local cause. They are in fact caused by a multiplicity of short movements into and out of the city; and it is not uncommon to find that the traffic on a main route approaching the city is thus swelled to several times its volume a few miles from the city limits. Unfortunately, it is not common to find the capacity of the highway proportionately enlarged. In consequence there is often on such relatively short sections of highway an actual development of congestion or an approach to it.
If we inquire into the reason for the failure to augment the traffic facility in proportion to the increase in traffic we usually encounter right-of-way difficulties. At the approach to the city road-bordering developments thicken to such an extent that the additional space required for the widening or other increase of the highway facility may be obtainable only at heavy cost because of the closely crowding suburban residences and industrial establishments.
Once inside the city, where the block plan offers alternate avenues of travel, it might be assumed that the congestion would be substantially relieved. In some instances a measure of relief is observed; but generally such a desirable condition is not realized. The particular street joining directly with the main highway at the city’s edge usually serves as a trunk line far into the city, generally to its very center. It thus conveys the in-bound traffic to convenient points of departure toward its ultimate destinations, and reciprocally collects the out-bound traffic at similar points. Frequently such a street is identified by United States or State route numbers as the direct inward extension of the external highway, so that strangers as well as local citizens are channeled into it. Quite often, particularly in the older cities of the East, the present internal street, which before the city’s growth was actually the external highway, still follows its historic radial course toward the center of the city, and cuts conveniently across the rectangular block plan of younger city streets. In alinement, the present street is in such cases distinctly the preferable route for much of the traffic entering the city; but its convenience on this score may be largely nullified by the fact that it retains the narrow width of the old country road it was meant to be. When this is the case, traffic conditions may become so bad, approaching the center of the city, as to force the abandonment of the route by the through traffic despite its convenient alinement. A condition of this sort is illustrated in plate 48.
