How Affordable is Transportation? A Context-Sensitive Framework

Transportation affordability refers to the financial burden households bear in purchasing transportation services. Traditional measures, which focus on what share of household disposable income or total budget goes to transportation services, often fail to consider the wide variation in households' transportation needs and locational settings. In this project, we propose a contextualized transportation affordability analysis framework that differentiates population groups based upon their socio-demographics, the built environment, and the policy environment. The necessity of such a context-sensitive framework is demonstrated via a case study of the Twin Cities metropolitan area, which shows heterogeneity among different population groups in terms of their transportation needs and resource availability. The proposed context-sensitive framework points to two dilemmas associated with transportation affordability. First, the socio-economically disadvantaged group has the lowest auto ownership rate, yet its transportation needs are better served by automobiles. Second, while automobiles can reduce transportation hardship for the socio-economically disadvantaged, the existing auto-oriented urban landscape in the U.S. requires more travel for access to destinations, which leads to higher transportation costs. The dilemmas call for a multi-modal transportation solution: reducing societal auto dependence and providing financial subsidies for car access among disadvantaged populations are equally important to enhance transportation affordability and social welfare.