to understand. Many studies in history, geography, spatial economics, sociology, or physics discuss various facets of the evolution of the city [@Mumford; @Batty; @Angel:book; @Fujita:2001; @Glaeser:2011; @Makse:1995; @Bettencourt:2007; @Marshall:2009; @Batty:2009; @Geddes:1949]. From a very general perspective, the large number and the diversity of agents operating simultaneously in a city suggest the intriguing possibility that cities are an emergent phenomenon ruled by self-organization [@Batty]. On the other hand, the existence of central planning interventions might minimize the importance of self-organization in the course of evolution of cities. Central planning –here understood as a top-down process controlled by a central authority – plays an important role in the city, leaving long standing traces, even if the time horizon of planners is limited and much smaller than the age of the city. One is thus confronted with the question of the possiblity of modelling a city and its expansion as a self-organized phenomenon. Indeed central planning could be thought of as an external perturbation, as if it were foreign to the self-organized development of a city. The recent digitization and georeferentiation of old maps will enable us to test quantitatively this effect, at least at the level of the structure of the road 