Nudging employees for greener mobility—A field experiment

The central issue of this paper is to understand how policy makers can design instruments to create incentives towards green mobility. With this in mind, we ran a field experiment in 89 French firms (both public and private organizations) over 54 weeks to investigate how nudges and financial incentives can decrease the use of polluting vehicles by employees during their commute to work each week. Based on data including 845 employees, our study highlights several results related to three important attributes of policy design: the type of instrument, the timing and the targeting. We find that individuals exposed to the nudges "Moral Appeal", "Risk of Loss", and a combination of these two, significantly decrease their use of polluting vehicles in their daily commute to work. We find no treatment effect, either for the other nudges or for the impact of financial incentives. Our findings also reveal a persistent effect in time of the three successful nudges on the transport behavior of employees. Using a causal forest method to evaluate the heterogeneous treatment effects of these three nudges, we demonstrate that distance from work and pro-environmental behavior are the strongest predictors of treatment effects. We find that the further the employees reside from their workplace, the lower the treatment effect estimates. It suggests that selective targeting can improve the effectiveness of the nudging policy.