Le Monde islamique, du Maghreb à l'Iran

Dossiers des Images Economiques du Monde [DIEM n° 26

Assessing Spatial Planning Policy with Accessibility Indicators: the case of Lille's Metropolis Scenario

This chapter presents an analysis of transport services in the context of regional transport planning. It proposes to use specially designed accessibility indicators, which allow to really apprehend the quality of the services supplied to different segments of the population and help to assess alternatives solutions. The methodology is applied to the case of Lille as a region capital, and in particular to its main stated objective of enabling people to reach the region capital in less than one hour from the major surrounding urban centres. The improvement of accessibility may be classically measured in many ways, especially using GIS techniques. Nevertheless, the classical accessibility indicators do not provide a correct measurement of the travel times through a scheduled transport system. The railway service architecture –the way omnibuses and expresses are associated in the transport supply– and the intramodal transfers cause strong bias in the usual measurements of the travel times. Moreover, the travel demand is strongly constrained by the daily urban rhythms and the location of the major traffic attracting activities. These are the source of difficult peak hours traffics to which transport supply should be better adapted. To deal with these problems, new accessibility measurements are proposed, which use scheduled graph modelling. They integrate the full information of transport time-tables of the regional rail transport system in order to model the transport supply of a usual week day. The accessibility measurements produced by this model provide an assessment of the way the transport system can address the spatial planning policy objective of setting the major regional urban centres within one hour of Lille