Note de recherche. Une estimation du lien entre forme urbaine et choix modal. Le cas de six aires urbaines françaises

Taking into account sustainable development for urban planning has led to question the interaction between urban form and daily mobility. The theory of the « three types » of city establishes that the available transport technology is a force which shapes the city (Walking City, Transit City, and Automobile City). Such an hypothesis constitutes a pertinent theoretical framework to explain the relationship. This article seeks to test the operationality of the theory, by analyzing the urban form-modal choice links for six French metropolitan areas. The technique used is an estimation of cubic spline functions. The results are as following : first, there is a modal split from « soft » modes of travel (walking and transit) to the automobile as the distance to the city-centre increases. Second, automobile is almost systematically used in the most remote areas ; the hypothesis of « automobile dependence » is useful to explain such a phenomenon, as we show by the analysis of the interaction between urban density and modal choice. These results validate the theory of the « three types » of city. Finally, we note a positive relationship between teleworking and the distance to the city centre, suggesting the emergence of a fourth type of city : the « Motionless City ».