Train or plane? Experimenting with social norms on Swiss train travellers

• How to increase long-distance travelling by train rather than plane? We focus on Swiss train travellers. • We manipulate injunctive and descriptive social norms to test their effect on transport mode choice. • We perform a survey experiment encompassing different travel time and price conditions. • Manipulating injunctive norms increases by 18% train choice under unfavourable conditions. • Policies should leverage testimonials/peer-to-peer initiatives to increase injunctive norms toward train use. Shifting the demand for long-distance travel from planes to trains is a key challenge for decarbonisation, as rail travel produces far fewer carbon emissions. However, travel time and price remain key determinants favouring planes. We conduct a survey experiment to test if social norms supporting train use for climate-protection reasons can consolidate train choice among current train users under unfavourable time and price conditions. In Switzerland, a well-connected country to European destinations by railway routes, we recruit individuals having recently performed one long-distance trip by night train. We collect their perceptions on social norms, inflate them, and randomly assign participants to either inflated injunctive or descriptive norm treatments or a control group. Participants then complete discrete choice tasks with varying travel time and price scenarios. Inflated injunctive norms increase the probability of train choice by up to 18% under disadvantageous conditions. We discuss policy implications on enhancing social norms to support long-distance travel decarbonisation.