Under What Conditions Can Urban Rail Transit Induce Higher Density? Evidence from Four Metropolitan Areas in the United States, 1990-2010.

Abstract

Previous studies that evaluate the land use impacts of the urban rail transit systems yield mixed results on whether and how these systems could affect land use forms. Those mixed results suggest that the existence and magnitude of land use changes due to rail projects are likely influenced by certain contextual conditions, pertaining both to the project location and to its regional setting. It is the focus of this study to explore what those conditions are and to examine how they could affect the land use impacts of urban rail transit projects on the nearby neighborhoods.

This study takes into account both the internal and external factors that could interfere with the land use impacts of urban rail transit. To provide the most recent evidence on this topic, this research selects four metropolitan areas in the United States as the study cases—Chicago, Denver, Los Angeles, and Washington, D.C., each of which constructed new urban rail lines in the 1990s. The findings on individual cases show that a new rail transit station is more likely to help increase population and housing densities when it is introduced in a moderate-income neighborhood with a pre-existing condition of compactness and relatively few single-family houses. A cross-comparison of the results from the four difference cases reveals that heavy rail lines are more likely to trigger increase in population and housing density than light rail lines. In addition, the network effect also matters—a new urban rail line that is an extension to an existing rail transit network is more likely to promote density increase than a brand new urban rail system built from scratch.

This study is the first of its kind to systematically study the interference of both the internal and external factors of a new urban rail transit project on its potential land use impacts. The findings of this study can be used to help transit planners make informed planning decisions on the site selection of a new rail station in the future, if densification is one of their planning goals.