Transport facing the challenge of the energy transition. Explorations between past and future, technology and sobriety, acceleration and slowing down.

Summary The thesis focuses on CO2 emissions from transport in France. It questions the alignment of public policies and current developments with the objective of achieving carbon neutrality in France by 2050. At this horizon, the national low-carbon strategy aims at an almost total exit from oil, by relying on 5 levers: moderation of transport demand, modal shift, better vehicle filling, energy efficiency, and energy decarbonization. The thesis studies (1) the evolution of these levers in the past, (2) their possible evolution by 2050, (3) the importance of mobility speed, and (4) the implications for public policies. It emerges that the acceleration of transport and the increase in demand that it has allowed have strongly pushed up emissions over the end of the 20th century. Since the turn of the millennium, these variables have been more stagnant, due to a combination of structural factors oriented towards saturation, and cyclical factors such as the rise in oil prices and the introduction of speed cameras. In the future, strong technological and sobriety evolutions will be essential to reach neutrality, requiring breaks with the current trajectories.