ABSTRACT
The history of planning in the United States is largely one of response to urbanization and the problems it has brought. This chapter discusses an account of urbanization of United States in the nineteenth century and from the beginning of the twentieth century to the present. For perhaps about the first half of the twentieth century, technology favored decentralization within metropolitan areas but did not favor smaller over larger areas. The distinguishing features of many nineteenth-century cities were concentration and density. The nature of nineteenth-century transportation contributed to an extremely dense pattern of urban development. In the late nineteenth century, the first signs of suburbanization became visible as the electric streetcar began expanding the old 'walking city'. In the twentieth century, automotive transportation, electronic communications, and increased income promoted massive suburbanization of population and economic activity, which continue to the present time. The presence of large numbers of children was a major force behind suburbanization.
