UC Davis Institute of Transportation Studies

There is widespread interest in reducing vehicle-miles of travel as a policy goal. Any progress toward that goal requires a better understanding of the potential for incremental reduction in vehicle use in the context of ubiquitous ownership and auto-oriented communities, as we have in the United States today. A key to incremental reductions in vehicle use may be new paradigms for using cars only sometimes, by sharing cars and rides. To explore this potential, this dissertation examines the use of cars outside of conventional ownership, among members of no-car and low-car households in the United States. I use the National Household Travel Survey to characterize the volume and nature of car use by levels of car ownership nationwide. Next I develop a method for estimating benchmark mobility levels based on demographic attributes, in order to evaluate overall mobility fulfillment among non-car-owners. Comparing fulfillment levels among different subgroups helps to identify circumstances in which nonownership does and does not indicate hardship. I supplement this quantitative nationwide assessment with a qualitative examination of the experiences of a particular subpopulation with limited vehicle access, recent immigrants to California from Mexico participating in focus group interviews. Collectively the results characterize most likely circumstances, social contexts, practical logistics, and overall mobility outcomes for those using cars outside of the context of conventional ownership. The findings point to circumstances in which innovative sharingenabling services might be adopted more readily. They also point to the circumstances in which services or policies might provide the most added value, filling important gaps, improving nonowner quality of life, and complementing overall vehicle-reduction goals.