ZEW Study: More Sustainable Business Mobility with Moral Appeal and Comparison

Companies can make an important contribution to reducing CO2 emissions through mobility budgets and corresponding communicative support measures. A field experiment by the ZEW Mannheim demonstrated that the use of cars within a mobility budget can be reduced through small, targeted prompts and social comparisons via email to employees.

“We were surprised by how consciously participants thought about their mobility options because of the emails. They actively decided to forgo car trips to reduce greenhouse gas emissions,” emphasizes Ulrich Wagner, ZEW Research Associate in the research area "Environmental and Climate Economics" and Professor at the University of Mannheim.

The car has the highest CO2 emissions among the modes of transport we examined. It is all the more noteworthy for policymakers that communication tools with clear prompts can ensure that people use cars less frequently, adds Johannes Gessner, a doctoral student at the University of Mannheim.

The 341 participants—all employees of a large German company—received emails from their employer over a period of eight weeks. From these emails, employees could see whether they used public transport more or less than other employees. For randomly selected recipients, this social comparison was supplemented by a moral appeal to prefer public transport for climate protection reasons.

Combination of social comparison and moral appeal

Based on the changes in mobility expenses, the researchers could determine a significant effect of this information on individual transportation usage. The combination of social comparisons and moral appeals leads to a significant change in mobility behavior. This finding contrasts with previous studies in the transportation sector, which considered social comparisons in isolation and could not detect any effects. The combination of social comparisons and moral appeals contributes in particular to reducing car mobility expenses. Parallel to this, expenses for micromobility, such as through e-scooters or bike sharing, increase.