In Europe, the idea that coordinating transportation and urban planning is a necessary condition for setting sustainable urban development into motion has spread throughout academic and professional circles. While this concern is not new, the objectives underlying transport and urban planning coordination have deeply changed over the last decades. How have local authorities translated the requirements and objectives of national laws? How have they accounted for the evolution of these global objectives ? What factors explain innovation and continuity in the relationship between land use planning and transport policies? In a comparative research between Switzerland and France, we addressed the question of political change by reconstituting the "trajectories" of four urban areas: Geneva and Bern in Switzerland and Strasbourg and Bordeaux in France. We have described the policy paths of these urban areas since the end of the 1960's by focusing on the contents of master plans, the principal technical solutions and projects that have been implemented, and the means of inter-sectorial coordination used. For each case, factors of change or inertia have been identified by focusing on three main variables that are often studied alternatively in public policy analysis: ideas, institutions and interests.