With rates of obesity, heart disease, and related health problems increasing in the U.S. many policy makers are looking for ways to increase physical activity in everyday life. Using a bicycle instead of a motor vehicle for a portion of everyday travel could help address these problems. This research aims to fill a gap in the existing literature on the effect of different types of infrastructure, such as bicycle lanes or paths, on bicycling. The project used global positioning system (GPS) technology to record where a sample of 164 adults in the Portland, OR region rode their bicycles. Data was collected from March through November 2007. The participants in this study were primarily regular bicyclists who usually rode more than one day per week, year-round. This report uses that data to address the four primary sets of research questions: (1) How often, why, when, and where do cyclists ride? How does this vary based upon rider characteristics? (2) How do cyclists? routes differ from the shortest network distance? (3) What factors influence cyclists? route choice decisions? How do personal attributes influence these decisions? (4) What is the difference in travel time between bicycling and driving?