The proportion of adjacent main-highway traffic generated by the smaller cities, either as points of origin or points of destination, depends a great deal upon the location of the city in relation to cities of larger population. A town of 2,800 population, such as Laurel, Md., located on the main highway midway between two such large cities as Baltimore and Washington, which are separated by only 30 miles, will be neither the origin nor the destination of a large part of the heavy traffic counted on the main highway near its boundaries. In contrast, a town of approximately the same size, such as Carson City, Nev., will be found to be the source or destination of a larger part of the lighter traffic on the highway connecting it with its somewhat larger neighbor, Reno.
Similarly, among slightly larger cities, the city of Milford, Conn., a city of more than 11,000 persons, undoubtedly is responsible, as origin or destination, for a comparatively small part of the heavy traffic on the great main artery near its city limits. Located midway on U.S. 1 between the neighboring larger cities of Bridgeport and New Haven, it is directly in the path of the New York-Boston movement.
Annapolis, Md., a city of 13,000 persons, is on the other hand, either the origin or destination of a much larger part of the traffic on the spur highway that connects it with Baltimore, 30 miles away.
Among the smaller cities differences of geographic location and intercity relationship may somewhat disturb the rule. It nevertheless remains true, and among larger cities almost without exception, that the larger the city the larger will be the share of the traffic on the approach highways that has its origin or destination in the city.
Furthermore, of this city-concerned traffic, the largest single element originates in or is destined to the business center of the city. This is the area in which are located the larger stores and warehouses, both wholesale and retail, the principal banks and other financial institutions, the seat of the city government and the courts, the bigger hotels and theaters, some of the larger apartment houses, and the more influential churches. Usually it includes the principal transportation terminals, some industrial establishments, and occassionally one or more high schools and other educational institutions, the art gallery and music hall and other cultural institutions. Generally it is also the site of the original settlement of the city.
The locations of the principal rail and water terminals have been powerful factors in shaping the business center. Within the forseeable future, this area is likely to remain the objective and the source of a large part of the daily street and highway traffic. It is reasonable to conclude, therefore, that the interregional routes, carrying a substantial part of this traffic, should penetrate within close proximity to the central business area.
How near they should come to the center of the area, how they should pass it or pass through it, and by what courses they should approach it, are matters for particular planning consideration in each city. Since these routes should be designed to serve important arterial flows of intraurban as well as interurban character, their locations from the fringes to the center of the city should be determined in large degree by the location of internal areas in which are generated important volumes of the intraurban movement.
