A multi-criteria approach for choosing a new public transport system linked to urban development: A method developed in the Bahn.ville project for a tram-train scenario in the Saint-Étienne region

The success of Transit Oriented Development (TOD) or rail oriented development depends on several factors, among them the characteristics of the public transport system should not be neglected. In the typical tram-train approaches as exemplified in the Karlsruhe experience, a new transport systems is proposed from the association of specific rolling stock, intermediate between tramways and trains, to a combination of urban tram tracks and existing conventional railway system. The adaptation to both central and peripheral contexts, and the promise of relatively low investment costs by reusing the existing infrastructure, explain the interest of such systems in metropolitan contexts. The tram-train approach combines urban considerations with functional characteristics of the transport system in order to provide new benefits in terms of accessibility, as compared to heavier systems. We propose to examine the project of the conversion of the regional rail Fraisses-Firminy-Saint-Étienne line into a tram-train corridor. This involves the introduction of a series of new stops that we want to assess: starting from a proposed list of stops, which ones should be introduced? To deal with this issue we have built a multi-criteria approach associating transport and urban considerations. The criteria include accessibility measurements, impact of each stop on the total travel time, catchment areas for population and jobs, existing urban functions in the neighbourhood of the stops, potential for urban development of housing, activities and equipment, potential for connection with other modes, and cost of construction. The multi-criteria analysis is able to provide some clear information about the opportunity of introducing each stop. The analysis raises some questions concerning three out of the seven new stops, and provides some relevant information for the decision processes.