Urban Decentralization

The diffusion of urban structures and functions outward from the urban core, or Central Business District (CBD). This process has occurred to some degree in metropolitan areas in the economically advanced countries because the advent of mass-transit systems in the 19th century, when trams, street cars, railways, and early subways allowed workers to live much greater distances from their places of work than had previously been the case. The development of such lines of transport allowed those with the economic wherewithal to relocate their places of residence further from the compact city center, along the various radiuses of the transportation network, resulting in a dispersion of city dwellers over a greater space. 

Residential clusters on the outskirts of the city were labeled “sub urban areas,” or simply suburbs. As the customer base decentralized in urban areas, businesses also began to relocate to the suburbs, especially those that offered goods and services that were low cost and purchased frequently, such as grocery stores, barbers, clothing, etc. Land developers frequently worked in coordination with transit companies, planning residential communities that would have ready access to the transportation system, because many residents continued to work in the CBD and therefore commuted into and out of the city on a daily schedule. In North America, urban decentralization was spurred after the 1880s by rising standards of living, advances in transportation technology, and rapid population increases. 

The period of greatest urban decentralization in the economically developed world occurred from the late 1920s to the 1970s. The affordability and convenience of the automobile, especially in the United States, resulted in an intensification of decentralization in metropolitan areas. After World War II, this movement became even more pronounced due to several factors, including a high rate of family formation, the availability of relatively inexpensive loans for home mortgages, and most importantly, the construction of the federal interstate highway system. Interstate highways were originally conceived as conduits for troops and supplies to major cities in the event of war, so the roadways were typically constructed directly through the heart of the city, adjacent to the CBD. 

By the 1970s, interstate bypasses, forming a loop around the city center, were common in many locations. This transportation geography led to the emergence of edge cities, so-called asylum suburbs, and related features of a decentralized urban landscape. Economic functions were also decentralized, and businesses that relocated toward the suburbs tended to cluster together in a single, concentrated space, the shopping mall, effectively displacing some of the benefits offered by the CBD. In the densely populated eastern seaboard of the United States, urban decentralization has resulted in an almost continuous band of urban development, the megalopolis. Some of the negative effects of urban decentralization include the economic decline of the inner city in many instances in the 1950s and 1960s; the appearance of so-called urban sprawl, characterized by vast tracts of land containing nearly identical homes; and greater social isolation of families and communities. Slowed somewhat by gentrification and other counter trends, urban decentralization continues to occur in many urban areas.