Bicycling as a form of ‘active transportation’ is an easy way to integrate physical activity into a person’s daily life. Bicycling in youth is especially beneficial because it provides physical activity at a time when youth obesity rates are soaring. Yet few studies have examined bicycling in adolescence. This study begins to fill that gap through an exploratory study of the formation of attitudes and practices regarding bicycling among residents of Davis, California, a mid-sized city in the United States where bicycling is normative. Participants, 25-65 years of age, responded to self-administered questionnaires and open-ended interview questions regarding their bicycling experience throughout their life course. In this paper, we focus on responses related to the “youth period”. Results showed that bicycling activity decreased during the youth period, as did positive attitudes towards bicycles and bicycling. High school youth, especially females, were particularly sensitive to negative images, even stigma, associated with bicycling. Bikes were abandoned for other modes of transportation, particularly walking and driving. To achieve a more bicycle-friendly society, communities must encourage bicycling and positive attitudes toward bicycling throughout the life course, particularly during the teen years when drop-off rates are high. This can be done by implementing bicycle promotion programs developed by and for teens as well as by implementing restrictive licensing or driving policies