Rebound effects, i.e. undesired behavioral changes in individual energy consumption, threaten technical efficiency gains. So far, the underlying mental mechanisms of rebound effects have rarely been scientifically investigated. The dissertation project adopts a psychological perspective on rebound effects and studies these effects in the context of car-based mobility. First, an adequate theoretical framework will be elaborated, based on psychological and sociological explanations for rebound effects as well as mobility-specific behavioral models and theories of environment related decision making. The empirical phase will then be carried out through a mixed-methods design: interviews and surveys with buyers of a new car, focusing on their purchase motives and changes in their mobility behavior. The empirical data will be analyzed in order to identify specific target groups for interventions and to gain insight into the moderating psychological processes of rebound effects. Finally, different political instruments to cut and prevent rebound effects will be discussed.