This study explores the factors associated with observed changes in transportation mode shares over the period from 2012 to 2017 (corresponding with the period between the two most recent household travel surveys conducted in California). In contrast with the goals of the California Department of Transportation and the State Transportation agency, walking, biking, and using transit all decreased during this period, and driving and the use of personal vehicles increased. There are a number of factors typically associated with transportation mode choices, including socio-demographics, attitudes, life stages, land use and infrastructure availability. Further, large scale events may also have an effect on travel trends; for example, the Great Recession may have impacted individuals’ ability to own a personal vehicle and therefore increased the use of alternative means of transportation during the years leading up to our survey period. Similarly, the 2013 passage of legislation allowing for non-citizens to obtain a driver’s license in the state of California, may have impacted mode shares over the study period. This paper compares these and other factors impacting mode shares in 2012 and in 2017 to answer part of the question about why we see this decrease in the use of active modes over this period and what types of planning, programs, and policy actions may help to reverse this trend and get California back on track to increase walking, biking and the use of public transit.
