Open space should be preserved. Smart Growth emphasizes balancing jobs and housing to reduce the reliance on automobiles and the resulting traffic congestion. The goal is to provide people with the opportunity to live near to where they work. The natural process of urban growth leads to a concentration of employment. In the early stages of metropolitan growth, jobs tend to concentrate in downtown business districts, which are the focus of the metropolitan transportation system.
Employers find it more profitable to locate at the urban center and bid up the price of land there.
Residential uses move to the periphery of downtown where land is cheaper and eventually, if growth continues, to the suburbs. Initially, the suburbs are simply bedroom communities. But as growth continues, the commute from the suburbs to downtown becomes increasingly difficult. Employment begins to move to the suburbs. As a consequence, the ratio of jobs to housing tends to grow over time in the suburbs.