Suburbanization is a term used to describe the growth of areas on the fringes of major cities. Sudden and extreme relocation out of urban areas into the suburbs is one of the many causes of urban sprawl, as suburbs grow to accommodate the increasingly large population. Many residents of suburbs still work within the central urban area, choosing instead to live in the suburbs and commute to work.
Suburbanization is caused by many factors that are typically classified into push and pull factors. Push factors are those that push people out of their original homes in urban areas into suburban areas. Pull factors are those that attract people to suburbs in particular. The main push factors in encouraging suburbanization have to do with individuals feeling tired of city life and the perception that urban areas are overpopulated, over-polluted, and dirty. Further, the mid-twentieth century movement of "white flight" significantly contributed to the rise of suburbs in the United States. The term refers to the large-scale migration of whites from racially mixed urban regions to more racially homogenous suburban areas. White flight began in earnest in the United States following World War II and continues, though in less overt ways, today.
For many of the families that fled the city in favor of the suburbs, the catalyst was the perception of racially diverse urban areas as lower-class and crime-ridden. Real estate law at the time enabled this process, as many minorities were legally excluded from purchasing properties in suburban areas. These racist practices, called redlining, barred African-Americans from pursuing home ownership, even when they could afford it. Suburban expansion was reserved for middle-class white people, facilitated by increasing wages in the postwar economy and by federally guaranteed mortgages that were only available to whites because of redlining. African-Americans and other minorities were relegated to a state of permanent rentership.
The effects of white flight are still seen today. Take, for example, the case of St. Louis, Missouri. St. Louis is a city surrounded by suburbs that are clumped together as the county of St. Louis. St. Louis County developed as whites fled the city for the suburbs. The racial makeup of the city St. Louis and St. Louis County still reflect the racial component of the county's origins. According to the 2010 United States Census, the city of St. Louis is 49.2 percent African-American, 43.9 percent Caucasian, 3.5 percent Hispanic, 2.9 percent Asian, and 0.3 percent Native American. By comparison, St. Louis County is 70.3 percent Caucasian, 23.3 percent African American, 3.5 percent Asian, 2.5 percent Hispanic, and 0.03 percent Pacific Islander. At the turn of the century, the racial disparities were even more exaggerated.
Pull factors for suburbanization at the turn of the century included more open spaces, the perception of being closer to nature, and lower suburban house prices and property taxes in comparison to cities. Certain infrastructure changes encouraged families to leave urban areas for suburban ones, primarily the development of the Interstate Highway System and insurance policies favoring suburban areas. Following World War II, President Dwight D. Eisenhower launched an initiative to create federal highways to allow for expansion outside of urban areas. Thus, the interstate highway project of the 1950s was developed with suburbanization in mind. Additionally, the government agreed to underwrite mortgages for suburban one-family homes. In effect, the government was encouraging the transfer of the middle-class population out of the inner city and into the suburbs. This movement is thought to have exacerbated urban decline in cities. Insurance companies also fueled the push out of cities and the growth of suburbs, as it redlined many inner-city neighborhoods. This means that insurance companies would refuse to grant mortgage loans to families seeking housing in urban areas and would instead offer lower rates in suburban areas; combined with the federal loans for single-family suburban homes, one sees a joint enterprise between both public and private entities to encourage suburbanization.
The mass movement of families from urban to suburban areas has had a serious economic impact with changes in infrastructure, industry, real estate development costs, fiscal policies, and more. As a result of the mass residential migration out of urban centers, many industries have followed suit. Companies are increasingly looking to build industrial parks in less populated areas, largely to match the desires of employees to work in more spacious areas closer to their suburban homes. "Making it to the suburbs" has become a modern iteration of the American dream. As residential wealth and corporations continue to leave urban zones in favor of suburban areas, the risk of urban decline increases.