Trips not Taken: Profiling the Extremes of Transportation Insecurity

• In Event: Understanding Food and Transportation Security and Policies to Address Them

Abstract

IntroductionThe extremes of transportation insecurity is the inability to take a trip because themeans is not available, a situation that negatively impacts an individual’s qualityof life. This study explores the socio-demographic attributes influencing transportationconstraints and how these vary across different geographic areas over time.Using data from the 2017 and 2022 National Household Travel Survey (NHTS), weinvestigate the spatial and temporal dimensions of trips not taken and assess itsimplications, particularly in the context of the COVID-19 pandemic.
ApproachWe conducted a spatial-temporal analysis using the NHTS data to profile individualswho self-report staying at home because of no transportation. Initial findingsrevealed variability in the proportion of affected individuals, ranging from 0.01% inrural New England to 1.02% in urban areas of the US Census West South-CentralDivision. Profiles were constructed considering socio-demographic factors to understand the travel constraints better. To enhance granularity, we applied rakingmethods to estimate trips not taken at a detailed geographic scale. Temporal shifts,particularly pre- and post-COVID-19, were analyzed using a Difference-in-Difference(DiD) approach, with 2022 as the treatment year. Weighted logistic regression andinverse probability weighting (IPW) were employed to adjust for non-random treatment assignments and uncover heterogeneity in treatment effects.
ResultsOur analysis highlighted substantial variability in how different groups experiencedtransportation barriers. Post-COVID-19, individuals with children and those holdingbachelor’s degrees faced increased travel challenges, with average treatment effects(ATEs) of 0.40 and 0.34 respectively, likely due to lifestyle adjustments or additional responsibilities. Conversely, older adults reported fewer barriers with an estimatedATE of -0.41, suggesting a resurgence in travel willingness. Further exploration ofpolicy interventions, such as increased disposable income through tax cuts or transfers, indicated potential reductions in unmet travel demand. Robustness checks confirmed the reliability of our findings, utilizing various specifications and imputationmethods.
ConclusionOur study provides a comprehensive framework for understanding the dynamics oftransportation insecurity and its underlying factors. By generating synthetic populations across diverse regions and time frames, we can estimate the volume of unmet travel demand and identify the causative factors. This methodology not only offers insights into how transportation barriers can be addressed but also serves as a valuable tool for transportation policy planning. Our approach, which emphasizes localneeds and conditions, could inform targeted interventions to mitigate transportationinsecurity effectively.

Authors

• TAYO FABUSUYI, University of Michigan Ann Arbor
  Presenting Author

• Yangyang Wang, University of Michigan Ann Arbor
  Non-Presenting Co-Author