From the "magic circle" to "automobile dependence": measurements and political implications

"Automobile dependence" is becoming an ever greater obstacle to sustainable transport policies. This dependence is due mainly to the fact that the positive effects for drivers of the growth of the automobile system are greater than the negative effects of traffic congestion. The model described in this paper is a simple one; it is based on an analogy with telecommunications systems and presents these positive effects in terms of accessibility. On the basis of the model, quantitative measurements of the French situation were made. Results show the importance of positive effects, which make it extremely difficult to reduce automobile dependence. Adopting a laisser-faire approach would only lead to very slow changes. Taxing automobiles and automobile use is not enough to offset the above-mentioned effects. Urban densification, beyond its segregative impacts brings little more than local solutions to a problem which is increasingly global. The author suggests the implementation of policies which would have a direct impact, within the automobile system, on the processes which generate these positive effects. The aim of these policies would be to diversify vehicles and their ownership, modify road networks (more, but slower, roads), and limit the capillarity of these networks. The policies proposed in this paper are both effective and realistic, since they aim to reduce automobile dependence, but not the quality of service provided to drivers.