Understanding what environments are comfortable (and perceived as safe) for bicyclists is essential for increasing bicycling, particularly for non-experienced riders. Surveys probing people’s qualitative perceptions about bicycling environments can inform bicycle planning in important ways. In this study, the research team used survey data from an on-line video experiment to analyze bicycling comfort and its relationship with person-level and road-level variables. They used an existing survey of students, faculty, and staff at UC Davis (n = 3089) who rated video clips of bicycling facilities in different environments based on their perceived comfort as a part of the annual UC Davis Campus Travel Survey (CTS). The video clips come from a variety of urban and semi-rural roads around the San Francisco Bay Area where bicycling rates vary. The results indicate considerable effects of socio-demographics and attitudes on absolute video ratings, but the research team found relative agreement about which videos are most comfortable and uncomfortable across our sample population segments. Presence of bike infrastructure and low speed roads are especially important in generating higher comfort ratings. However, the results suggest that even the best designed on-road bike facilities (according to attributes in our data) are unlikely to provide a comfortable bicycling environment for those without a predisposition to bicycle. Nonetheless, the results provide guidance for improving roads with on-street bike facilities where protected or separated facilities may not be suitable. The research team discusses these results in the context of design standards for bicycling and methods for prioritizing bike infrastructure investments.