The current study (of the TAPAS project) aimed to ascertain which factors, both psychological (mental) and physical (practical), were acting as the greatest determinants for bicycle commuting propensity of the working (or studying) population of Barcelona, Spain. Methods: Adults [N=795; 51% female, 87% nationals. Mean ± standard deviation: age = 37 ± 10, body mass index = 23.5 ± 3.3] who commuted to work or school in Barcelona responded to a comprehensive questionnaire (via telephone) concerning their commute activity and attitude. Respondents were categorised as either frequent or infrequent...