Understanding the acceptance and design of personal CO2 budgets for mobility: Insights from an intervention study

Kurzfassung

As the world strives to meet ambitious climate goals, policy measures to restrict personal carbon dioxide (CO2) emissions especially in the area of transport become paramount. This study, which is part of the pan-European research MyFairShare funded under the JPI Urban Europe ERA-NET Cofund Urban Accessibility and Connectivity (ENUAC), investigates the concept of personal CO2 budgets for mobility and its potential to drive behavior change towards lower emissions transport modes. The idea behind the CO2 budget is to break down nationally agreed CO2 reduction targets into the individual share of each citizen and to assign corresponding personal allowances for the CO2 emissions of the means of transport used. In the project, we developed a definition of fairness and investigated what a fair distribution of CO2 budgets would look like. When it comes to climate policy in the transport sector, a fair distribution of the burden is crucial for acceptance and social justice. In this context, the concepts of transport or mobility justice or transport poverty offer relevant starting points. In recent years, driving bans have been imposed on diesel vehicles, emission limits have been tightened and the CO2 pricing on road traffic has been introduced. Buying and using a private car will become more expensive and the proportion of people with limited mobility options will likely increase. This raises questions of social justice, especially for households that are dependent on a car due to their living and working conditions. A policy to prevent mobility poverty is needed that promotes social justice and climate protection at the same time and ensures that people can carry out their everyday activities with the lowest possible CO2 emission, regardless of their income or place of residence or work . This study aims to investigate how a personal CO2 budget for mobility could contribute to CO2-reduced mobility behavior and how it can be designed in a way that it is perceived as fair. The study was conducted in Berlin, Germany, one of the six living labs in the overall project exploring and testing the potential of mobility related CO2 budgets in different settings. In general, mobility budgets could serve as an instrument in the transition to a sustainable transport system supporting individuals in meeting their CO2-targets and indicating the need for improved transport services to decision-makers. Using a qualitative approach supplemented with app-based GPS tracking, we aimed to identify barriers and potentials related to personal mobility CO2 budgets and to develop measures to enhance acceptance and compliance with CO2-emission limits. The GPS tracking data was less intended to be used to spatially analyze the movements of the probands. Rather, we used the tracking as a stimulus: Through the tracking task we wanted to get the probands to engage with their actual mobility behavior and encourage them to think about their daily trips, their mode choices and the resulting emissions. Our intervention study presented our participants with personalized information regarding their allocated and consumed CO2 budgets across different transport modes on a daily basis, alongside general information on CO2 emissions and climate change mitigation. Our hypothesis was that commuters would change their travel behavior upon receiving daily information on their mobility budget consumption and transport emissions. The analysis of nine participant interviews revealed insights into knowledge gain, behavior adaptation, and the impact of information on behavior. Moreover, we explored the fairness of different CO2 budget designs, including equally distributed budgets, socially distributed budgets, and budgets with trading options. Our findings underscore the importance of providing valid information, individualized calculation and transparency regarding CO2 emissions to foster acceptance of restricted mobility-related emissions. We also identified objections and preferences regarding different CO2 budget designs. Notably, while socially distributed budgets that take the living conditions into account were preferred, trading options were mostly met with skepticism due to concerns about fairness, social equity and effectiveness. Our paper presents and discusses the findings from the interviews with special regard to the barriers and potentials as well as the acceptance of the three different design options of a personal mobility budget. In the conclusion, we provide recommendations for the introduction and design of personal CO2 budgets for mobility, emphasizing the need for transparent communication, consideration of social criteria, and careful implementation strategies to ensure fair outcomes and widespread acceptance.