Road safety concerns are a legitimate concern when promoting increased bicycle use. Currently, bicyclist traffic fatalities and injuries present both a public health concern and a disincentive to people taking up or continuing to bicycle for transportation. Bicycling is not an inherently a dangerous activity; automobile drivers pose the most risk of harm in crashes with bicyclists. Despite that, drivers' attitudes and behaviors toward bicyclists have not enjoyed much systematic study, particularly in the United States. This research explored the dimensions of drivers' attitudes toward bicyclists, including implicit bias and social attitudes, and examined the relationships between these attitudes and drivers' self-reported behaviors. The online survey included a cognitive test of respondents' implicit preference between drivers and bicyclists. The research questions are detailed in extends the analysis to drivers' self-report behaviors, and how demographics, individual travel behavior, attitudes, and the built environment predict drivers' behaviors related to bicyclist safety. The dissertation concludes with a discussion of the contribution to the literature on driver attitudes and behaviors, and the implications for both practice and research.ii Dedication This dissertation is dedicated to my parents, for providing me with all the opportunities in the world; my sister for her support and, when needed, tough love; and my niece, for whom I wish the brightest and happiest future.iii Acknowledgments