National Center for Sustainable Transportation

The California Department of Transportation set a goal of doubling walking and transit use and tripling bicycling in the state between 2010 and 2020. However, the most recent comprehensive travel surveys, the 2012 California Household Travel Survey (CHTS) and the California results from the 2017 National Household Travel Survey (NHTS), suggest that the state is moving in the wrong direction. These surveys seemed to show that a smaller share of trips were made by walking or biking in 2017 than in 2012, while private vehicle mode share increased. It is unclear whether the decline represents real changes stemming from various demographic or other factors or is instead related to methodological differences between the two surveys. Researchers at the University of California, Davis used the publicly available 2012 CHTS and 2017 NHTS California add-on data to examine the impact of methodological differences on the changes in mode shares over this five-year period and conducted a preliminary investigation into the role of demographic and other factors in these changes. This policy brief summarizes the findings from that research and provides policy implications.

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