This book deals with the reconciliation of the global challenge that is climate change and the local and sectoral solutions that need to be accurately implemented to remedy to it - as efficiently, equitably and acceptably as possible. If the urban scale is the most relevant stage for reducing transport-related CO2 emissions, it places the economic appraisal of mobility policies in a context far from the "academic ideal", notably because of the presence of overlapping externalities and the difficulty to assign an instrument to a policy target. Therefore, we formalise key conditions and assert...