Research

The project: A lack of reliable transportation can exacerbate symptoms of poverty and in some cases even cause poverty by making it difficult to secure employment or access services. Yet transportation is often overlooked as a dimension of poverty. Currently, mobility is measured by single factors like car ownership or neighborhood accessibility. Creating a new Transportation Security Index could provide a more comprehensive measure of whether people can travel where they need to go, regardless of mode of travel or neighborhood context. Modeled after the Food Security Index that raised awareness of hunger in America, the Transportation Security Index aims to offer new insights on how transportation-related policies and programs affect poverty and socioeconomic mobility.

The process: Based on a survey of 511 people, the investigators organized symptoms of transportation insecurity into six categories: lateness; skipping trips; spending a long time planning, waiting, or traveling; social isolation; feeling unsafe; and worrying. Those categories were used to inform survey questions for the preliminary Transportation Security Index, and the approach and analysis has undergone two rounds of peer review.

Results: The study found there are two dimensions to transportation insecurity: material and relational. The 16-question preliminary Transportation Security Index survey asks about material impact like being late getting somewhere or feeling stuck at home, as well as relational impact like feeling embarrassed about a lack of transportation and worrying about inconveniencing others due to a need for help with transportation.

To validate the preliminary Transportation Security Index, the researchers fielded a nationally representative survey in May 2018. The analysis revealed that a slightly modified Transportation Security Index is an effective tool that can be used to uncover transportation insecurity across different samples. The findings were published a 2021 Survey Practice journal article, and these results will inform articles on the correlation of transportation insecurity and other types of hardship associated with poverty. Also, parts of the Transportation Security Index survey have been used to study food insecurity among U-M students and as part of a neighborhood survey by Detroit Metropolitan Area Communities Study.

Alexandra K. Murphy, PhD, Assistant Professor, Department of Sociology & Faculty Associate, Population Studies Center, University of Michigan
Jamie Griffin, PhD, Assistant Research Scientist, Survey Research Center, University of Michigan
Alix Gould-Werth, PhD, former Adjunct Assistant Research Scientist, Population Studies Center, University of Michigan & Researcher, Mathematica Policy Research