Smart Growth and The Transportation-Land Use Connection: What Does the Research Tell Us?
The connection between transportation and land use plays an important role in both explanations of sprawl and estimates of the costs of sprawl. Transportation and land use are inextricably linked in two basic ways and many more subtle ways. First, transportation investments and policies influence development patterns: commercial development stretches out along highway corridors, new subdivisions pop up after the new freeway opens, shopping malls and gas stations congregate at interchanges. In this way, transportation investments contribute to sprawl, but they can also be used as smart growth strategies to help to fight sprawl. Second, development patterns shape travel patterns: the design of suburban areas makes transit and walking a challenge, the separation between land uses in low–density developments makes driving a necessity. In this way, sprawl contributes to automobile dependence, but smart growth policies to fight sprawl can reduce automobile dependence. Both theory and intuition tell us that this is the way the world works. But empirical evidence is surprisingly mixed, at least with respect to the impact we can expect from smart growth policies that depend on these relationships. The mixed evidence leaves plenty of room for debate.