Although environmental problems are often discussed as typical examples of social dilemmas, very little applied research has been done to better understand behaviour in real-world social dilemmas. The present study is aimed at examining to what extent psychological motives influence behaviour in a real-world social dilemma. The results suggest that the social dilemma paradigm can contribute to the better understanding of car use. Selective car use was dependent on individual as well as collective utilities. Moreover, different psychological motives that enhance co-operation in social dilemmas appeared to be correlated, i.e., the more respondents valued the collective interest, the fewer psychological barriers they faced to contribute to the solution of collective problems.