Rethinking the political challenges of the mobility transition through a “social contract” approach

The mobility sector offers a particularly vivid illustration of the social and political challenges posed by the ecological transition. Its environmental footprint is substantial, and reducing it requires a sustained combination of technical innovation, investment, and changes in practices. Mobility also plays a central role in daily life, making related issues (public policies, taxation, etc.) highly sensitive. At the same time, questions of justice are central to this sector. Measures affecting mobility involve issues of resource distribution and therefore equity: distribution of access to infrastructure, use of public space, sharing of financial costs, and allocation of public funding. As such, the evolution of mobility inevitably gives rise to political debate. Current controversies around low-emission zones (LEZs) are a case in point (Loisel et Rio, 2025; Braud, 2025). Tackling these challenges requires medium-term work that supports policy debate on the mobility transition through complementary data and analytical methods—an area in which the Institut Mobilités en Transition is actively engaged.
For several years, IDDRI has developed an approach centred on the idea of social contracts and on lifestyles, aimed at better understanding the social and political conditions for a successful ecological transition. This work rests on two key observations. First, the ecological transition, given its scale, is disrupting an established set of rules on collective life, and it is unfolding in a context already marked by inequality. The concept of a social contract reflects this reality and points to the need to renegotiate new arrangements. Second, the lifestyle changes required by the ecological transition (how we eat, travel, etc.) demand that we pay close attention to the conditions and people’s capacity to change, as well as differences in capabilities, resources and aspirations between different social groups. We recently applied this differentiated approach in a novel food transition scenario (TRAMe2035).
This article marks the beginning of a collaboration between IMT and IDDRI on these themes. It proposes a method for understanding the social pact for mobility and offers an analytical framework for identifying the risks of controversy, resistance and setbacks in the implementation of mobility transition policies. By combining sociological and political insight with technical and economic analysis, this approach aims to enrich and refine current assessments. It seeks to strengthen the capacity to implement the ecological transition while contributing to the development of a more equitable mobility system.