UC Davis Institute of Transportation Studies

This dissertation is about bicycling as a mode of transportation. More specifically it is about how road environments influence perceptions of safety and attitudes about bicycling, and how policies aimed at changing the road environment might influence travel behavior more broadly. In this dissertation the researcher presents three distinct studies that are all connected by this fundamental relationship between road environments and bicycling. In the first study, he examines bicyclist acute psychological stress in different road environments through a cross-over field experiment. He finds evidence that bicyclist stress is least for low speed and low traffic roads, but less reliable evidence for differences in stress between road environments with more subtle differences such as presence of bike lanes. Furthermore the researcher finds that psychophysiological measures of bicyclist stress are difficult to validate. While psychophysiological measures may hold near real-time, objective reflections of stress, it is still unclear if they offer more than survey measures of bicycling experiences in determining attitudes and behavior.

In the second study, the researcher examines the relationship between road environments and bicyclist route behavior through two observational case studies in Davis and San Francisco, CA. Bicycling route behavior in a small bike friendly city (Davis) by a predominantly student cohort with a wide range of bicycling experience, indicates that route detouring from shortest paths is minimal, and that bike lanes and off-street paths have uncertain effects of routing decisions. Conversely, bicyclist route behavior in a large city with a growing number of bicyclists (San Francisco) by a presumably more experienced and confident bicyclist cohort shows larger route detouring. In addition, the researcher finds evidence for a strong influence of protected bike lanes and off-street paths, and a less but still certain influence of conventional bike lanes on routing decisions.

In the third and final study, the researcher examine students’ usual travel mode to school at three northern California high schools. He finds that road environment characteristics such as bike lanes and off-street paths along plausible routes to school have a strong effect on the decision to bike to school. Furthermore he finds that attitudes such as a feeling of social pressure to bicycle have a strong correlation with bicycling. The combined results from these studies and review of the literature demonstrate that large scale changes to road environments may be needed to influence bicycling perceptions, attitudes, and behavior.