Are land use planning and gasoline price increase mutually supportive in getting more transit riders in the US urbanized areas?

In July of 2008, the United States had the highest gasoline price in both nominal and real dollars since the 1950s. As a result, there was a record mass transit ridership increase in the following months. Urban planners have long argued that land use measures (dense, mixed-use, and well-connected developments), transit policies (public subsidy for both operation and infrastructure investment), and a combination of both (transit-oriented development) would attract choice riders to mass transit; however, the rise of motor fuel costs was found to be the greatest factor to influence how people choose their travel modes. For this reason, previous research focused on a statistical relationship between gasoline price fluctuation and transit ridership change, and attempted to quantify that correlation by calculating the price elasticity of gasoline. However, that research ignored the influence of urban form and urban policy on the relationship between gasoline prices and transit ridership. This thesis focuses on the role of urban form and urban policy in this context and conducts an econometric analysis to see whether there are “synergistic” effects between “urban form and urban policy” and “gasoline price change.” A synergistic relationship means that the effect of adopting two policies at the same time yields better outcomes than the effect of individually implementing either of the two. However, quantifying the pure effects of land use measures on transit ridership is beyond the scope of this thesis; instead, this thesis attempts to calculate “interaction effects” of urban form and urban policy and gasoline price change. Based on an analysis of the largest 68 urbanized areas in the US from January 2002 to February 2010, this thesis finds that urbanized areas with either high population density or compact developments (urban form), and extensive urban containment policies (urban policy) are more sensitive to gasoline price changes, meaning that these areas show a greater ridership increase when motor fuel costs rise. Proponents of land use policies can use the above findings to support compact development and growth management policy. Also, transportation planners who find effective ways to reduce greenhouse gas emissions from automobiles are able to consider not only transit investment but also environmentally sustainable urban form. Because each urban area has different transit systems, urban forms, and urban policies, planners must identify the best ways for their own situations and implement customized policies for the long run. Although land use measures are less effective than a gasoline price change in the short run, long term applications of land use policies will make a difference that pricing policies alone cannot achieve