Does habitual car use not lead to more resistance to change of travel mode? SEBASTIAN BAMBERG 1 , DANIEL RÖLLE 2 & CHRISTOPH WEBER 2 1 Department of Social Psychology, University of Dresden, D-01062, Germany; 2 Institute of Energy Economics and the Rational Use of Energy, D-70550 Stuttgart, Germany Key words: habit, past behavior, reasoned action Abstract. An experiment examined the effects of an intervention (combination of information and a free public transport ticket) in a changed decision context (moving to a new residence) on travel mode choice by car users. If past frequency of car use has resulted in an automatic response to goal-related cues, one should expect resistant to change of travel mode. However, the results failed to show this. Neither past behavior or a direct habit measure predicted future travel behavior. Instead, the intervention influenced attitude, subjective norm, and perceived behavioral control, and consistent with Ajzen’s theory of planned behavior, these were the main causes of the change of travel mode. 1. Introduction It has been argued that past behavior is the best predictor of future behavior. However, this could reflect a statistical association. Past behavior may simply be a proxy for the causal effects of other psychological factors. For example, Ajzen’s (1991) theory of planned behavior (TPB) postulates that behavior is guided by beliefs about the likely consequences of the behavior (attitude), beliefs about the normative expectations of others (subjective norm), and beliefs about the presence of factors that may facilitate or hinder perfor- mance of the behavior (perceived behavioral control). In combination these three factors lead to the formation of a behavioral intention which is the imme- diate determinant of behavior. According to the theory, behavior is thus assumed to be reasoned, controlled, or planned. The TPB has been challenged by the argument that human behavior is habitual or automatic (e.g. Aarts & Dijksterhuis 2000; Aarts et al. 1998; Bagozzi 1981; Fazio 1990; Ouellette & Wood 1998; Ronis et al. 1989; Triandis 1977). Measures of past behavior have played an important role in attempts to test the validity of this argument. If behavior is always reasoned, then frequency of prior behavior should only have an indirect link to later behavior since its effect would be mediated by intention and perceived behavioral control. However, in regression analyses past behavior is typically found to Transportation 30: 97–108, 2003  2003 Kluwer Academic Publishers. Printed in the Netherlands.