The motivational impact of incentives to promote sustainable travel behaviour

Global environmental problems stem for a large part from human activities. Mitigation of such problems therefore can be realised if people consistently engage in sustainable behaviours. To motivate people to act sustainably, various incentives can be implemented. Current measures to encourage sustainable behaviours often rely on incentives that target people’s extrinsic motivation (e.g. monetary rewards); that is, their motivation to engage in sustainable behaviour in order to attain some external desired outcome. Such incentives often come with negative side effects, notably the crowding out of intrinsic motivation, resulting in mere short term behaviour changes (Bolderdijk & Steg, 2015). However, to the best of our knowledge, this crowding out effect on intrinsic motivation has not been explicitly measured in previous intervention studies. Thus, the current research aimed to test the motivational impacts of financial incentives to promote long-term sustainable behaviours. To do this, we evaluated the effectiveness of a three-week free public-transport card intervention, and its impact on people’s intrinsic motivation to commute to work using public transport. We found that participants consistently chose to commute to work using public transport, when they could do so for free. However, participants reported low intentions to continue to commute to work using public transport after the three-week intervention trial had finished. Interestingly and contrary to previous research, we did not find a crowding out effect of intrinsic motivation to commute to work. Implications and future research are discussed.