U.S. communities are becoming increasingly automobile dependent, with car use embedded in U.S. policies, practices, and preferences. To encourage transit use, transit systems too will require supporting policies, practices, and preferences. Light rail is currently enjoying some supportive policies, but research is just beginning to explore how psychological experiences might help support a switch to rail use. We propose a transactional approach to behavior change in which societal, physical environmental, and inter- and intrapersonal factors combine to support a new behavior. We illustrate this perspective at a university host site for the 2002 Olympics, where temporary parking shortages, the opening of a new light-rail transit line, and an outreach program enhanced the attractiveness of transit. Transit use was maintained by psychological satisfactions such as enjoyment of productive and pleasant activities during the ride, positive evaluations of the service qualities of light rail, and the view that light rail enhanced city livability. Results support the transactional approach and suggest directions for actions in transit promotion, environmentalism, and urban design.