Transportation equity
Income moderates the nonlinear influence of built environment attributes on travel-related carbon emissions
Tao Tao
Policymakers have adopted built environment policies to modify people’s travel behavior and the related emissions. However, most studies have not examined the interactive impact between income level and built environment attributes on travel-related carbon emissions (TCE), and only several studies consider their nonlinear relationships. With data from the Twin Cities, US, this study estimated the nonlinear effects of built environment attributes and demographics on TCE. It further examined the interactive impacts between household income and built environment attributes. The findings highlight that demographics exert a greater influence on TCE than the built environment. Employment status, job accessibility, and gender are the most important predictors. Besides individual nonlinear relationships, household income and built environment attributes have salient interactive impacts on TCE. The results suggest that providing environment friendly and affordable transportation choices to low-income population, switching to clean energy vehicles, and offering more matched job opportunities to low-income population near their residence are promising to create a sustainable transportation system.
[Under review]
Exploring the interaction effect of poverty concentration and transit service on highway traffic during the COVID-19 lockdown
Tao Tao and Jason Cao, 2021. Journal of Transport and Land Use, 14(1), 1149–1164.
During the COVID-19 lockdown, transit agencies need to respond to the decline in travel but also maintain the essential mobility of transit-dependent people. However, there are few lessons that scholars and practitioners can learn from. Using highway traffic data in the Twin Cities, US, this study applies a generalized additive model to explore the relationships among the share of low-income population, transit service, and highway traffic during the week right after the stay-at-home order. Our results substantiated that transportation impacts are spread unevenly across different income groups and low-income people are less able to reduce travel, leading to equity concerns. Moreover, transit supply influences highway traffic differently in the areas with different shares of low-income people. Our study suggests that transportation agencies should provide more affordable travel options for the areas of concentrated poverty during the lockdown time. In addition, transit agencies should manage transit supply strategically depending on the share of low-income people to better meet people’s mobility needs.
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