The Spread Of The Urban Spatial Structure And Its Effects

The development of American cities has been experiencing the great changes of the urban spatial structure, among which the development of suburbs is eminent. "Suburbia has become the quintessential physical achievement of the United States." "The United States is the vvorld's first suburban nation" and the evolution of American suburbs has tjpical significance. 1920s-1970s is the important development period of the suburbanization of the United States, during which America had finished the transformation from urban nation to suburban nation, so the thesis chooses the suburbanization of the United States (1920s?970s) as its research object and uses the theory of Modernization as its guidance.The suburbanization's growth of the period can be clearlv divided into two stages vvith World WarII as their watershed: 1920s-World War II and World WarII?970s. The suburbanization before World War II was limited to population shift and had limited development, while the suburbanization after World WarIIwas deeper and faster than that before World War II. Besides population shift, there were economic movements spreading out and the political centers lying in the suburbs accordingly. The suburbanization of the United States was prior to the other countries in the world, vvhich had its own characteristics: it mainly was a process of natura! spread from the city 鎜re to the outer; during the process, it was very obvious that the social stratum differed according to region; besides, it also presented the characteristics of extension with low density and decentralization.The suburbanization of the United States had its own historical causes. The development of modern productive forces was the essential impetus of it, among vvhich the technology force was the most active factor. Mass production of cars and cheap suburban houses with the assembly line promoted the suburbanization's grovvth. Besides, there were three other factors related to it. The federal government carried out the housing policy and highway act vvhich were beneficial to the suburbanization. The measures of HOLC and FHA also promoted it. The large quantity of highways subsidized by the federal government stimulated cities to spread out and diffuse further. The grovvth of American productive forces made its economic structure transform from the pattern of the secondary industry to that of the third estate. Thecharacteristics of the third estate made itself accustomed to the form of the diffusive development of the suburbs, so it became the powerful lever of the suburbanization. American culture and mental orientation also vvere one of the factors which promoted the suburbanization. The American people adore rural life, enjoy living in seclusion and value privacy and private space. Realizing the suburb ideal and seeking the combination of the advantages of the urban life and the rural life were the tradition which the American people had been pursuiting in their 200 years history. In short, the suburbanization of the United States was pushed forvvard by the modernization of the United States, with the premise of modem productive forces' development, with the factors acting together, such as the federal government's intervention, the economic structure's change, the American culture and mental orientation, and so on. The suburbanization kept pa鑕 with the modernization of the United States and was an important component of it.Conversely, the suburbanization caused the modernization some positive effects as well as negative effects. The positive and negative effects are as follows: it enlarged the middle class, \vhich was helpful to the achievement and fulfillment of the historic mission of American modernization; but meanvvhile, it also caused the central cities' recession and made the phenomenon of race segregation eminent, to some extent, it once impeded the development of the moderization of the United States. But ali in ali, the positive effects are primary and first, while the negative effects are subordinate and secondary. The suburbanization ha...