National and metropolitan trends in public transit use, transit-related walking, and ridesharing between 2009 and 2017.

Introduction: Walking is a common form of physical activity and is the most frequent way to access public transit. On-going changes in the US transportation system are occurring, notably increases in smartphone application-based ridesharing. The goal of this research is to assess whether increasing use of ridesharing was associated with a change in transit-related walking. This is important to both public health and transportation, as it can inform changes in active transportation which promotes both physical activity and transit use. Methods: We examined the association between change in transit use, transit-related walking, and ridesharing nationally and for selected metropolitan areas using the 2009 and 2017 National Household Travel Survey (≥18 years; n = 263,572 and n = 230,592, respectively). Analyses were conducted in 2019. Covariates included sex, age, race/ethnicity, education, employment, work from home, household size, number of vehicles, population density, Census region, metro area size and heavy rail transit category and season. Results: The national prevalence of transit use in the past month in 2009 was 16.9% (95% CI: 16.4%-17.4%) and in 2017 was 16.1% (15.6%-16.6%), a significant decrease (p < 0.02). The prevalence of daily transit-related walking in 2009 was 4.2% (4.0%-4.4%) and in 2017 was 4.4% (4.2%-4.6%; p = 0.22). The prevalence of daily taxi use in 2009 was 0.5% (0.4%-0.6%) and taxi/rideshare in 2017 was 1.1% (1.0%-1.2%), a significant increase (p < 0.0001). The relationships remained after covariate adjustment. Finally, there was not a significant change in transit-related walking or interaction between year and taxi/rideshare use after additional adjustment for taxi/rideshare. Changes in transit-related walking in metros were largely not significant, whereas increases in taxi/rideshare were largely significant. Conclusions: Results suggest that increased use of ridesharing may not be linked with changes in transit-related walking. Continued surveillance of travel mode prevalence is required to track potential reductions in population-level physical activity with technology-related changes in travel.