the possibilities of quick and individual daily transportation thus afforded.
Suburban business centers have followed the clustering of suburban homes. The more recent growth of the parking problem with its attendant difficulties of retail trade in the central business section, has to a limited extent induced an outward movement of some large emporiums and a more numerous establishment of branch and chain stores in suburban communities.
Modern industrial processes, requiring more ground space than is available at permissible cost within the city, have been and will continue to be the cause of a preference for outer locations as industrial sites, and the most favorable locations are those best served by transportation facilities, including highways.
From the standpoint of the city, as a corporation, a serious effect of the outward movement of residence, business, and industry has been the depreciation in value of city-contained land and property available by taxation for the financial support of the city government and the various services it must supply to its residents.
And finally, another disadvantage, affecting important city interests, has been the increasing tendency toward the diversion of trade from established retail commercial concerns located in the central business district to enterprises newly founded in outer sections, often without the city boundaries.
What the city will be like in the future depends on whether its future development is planned or haphazard. Several new conditions, however, will greatly affect city development. One of the most important of these is that future population growth of cities will be limited. To base the planning of highways or anything else on expectations of urban population increases like those of the past, would seem to be unwise.
Twenty-five years ago there was virtually{no control of growth and city development through city planning. Today many cities have plan commissions and a city plan in some stage of development.
Urban planning is really just now coming to grips with one of the basic urban problems—decentralization or dissipation of the urban area to an extent not economically justified, This is a most difficult problem to solve. So long, however, as the central areas of the cities are poor places in which to live and rear children, people will continue to move to the outskirts. Undoubtedly a factor that has facilitated this movement has been the improvement of highways.
If for any city, maps are prepared representing in bold silhouette the areas of the city and its environs occupied by buildings at definite successive periods of its history, it is possible to obtain a clear idea of the manner of the city’s growth. The series of such maps for several cities (fig. 26) illustrate typical growth processes common to many cities.
One of the most striking revelations of these maps is the manner in which, in the more recent periods, the growth of the cities has been extended outward in slender fingers along the main highways entering the city. This is undoubtedly due to the improvement of the main highways, which has resulted in a relatively satisfactory connection of bordering areas with the city.
