This paper presents the results of an experimental study on designing for self-efficacy in a game based driving simulator. Self-efficacy refers to how people´s beliefs in their capabilities affect their actions. The results show that the design of the feedback system can be used to increae self-efficacy measures thus affecting performance in a driving simulator environment. Self-efficacy has consequences not only for the performance of the particular task, but also for what activities he/she chooses to engage in and the persistence invested in them. Hence we find the results from this study relevant to various aspects of serious games design.