Tram-train, or the Energy of Short Distances in Strasbourg Metropole

The object of this research is the "city of short distances" which is emerging in recent debates as a sustainable energy model for the development of the metropolitan territory. It prioritizes the accessibility of services and housing and favors public transport and soft traffic - cycling and walking. Inspired by the polycentric system of German, Swiss and Dutch cities, this concept is in line with the philosophy of sustainable development since it integrates environmental notions: the fight against urban sprawl, the promotion of functional and social diversity, and sustainable travel. In the French context, Strasbourg seems to be an exemplary case study, whose cross-border dimension and positioning in the Upper Rhine have enabled it to develop according to the polycentric system of Rhine cities. Because of the density of its poles and the fine mesh of its transport networks, it is structured as a city of short distances, destined today more than ever to be organized around three entities: the metropolitan core; the less dense metropolitan area, but with a relative mix of urban functions; and the peripheral communes, organized around economic poles or public transport nodes (PLU-EMS, tome 1, 2015). In a dynamic of energy transition, the Eurometropolis also emphasizes in its development projects the quality of life, the modal share of public transport, especially those related to light rail, and the development of economic activities around dense metropolitan poles.

Based on our field of expertise and the specificity of our object, the main objective of the research was to understand the potential in terms of energy resources - linked to the issue of transport and mobility - of a metropolitan development system that places short distances, intermodality and density (around stations) at the heart of the project. More specifically, the questions focused on both the energy efficiency (doing more with less) of transport itself in the development policies of the territory, and on the energy efficiency of travel (allowing behaviors to change) in the territory lived and practiced.

The research was structured around three lines of investigation:

- Observations related to the theme of energy in the territory project of the Eurometropolis of Strasbourg.
- Historical and spatial analyses of the model of the city of short distances as it appears in Strasbourg and, by contrast, in other world metropolises
- Analysis of rail infrastructure and sustainable mobility policies in the territorial scenarios for Strasbourg 2030.

The general hypothesis was that the city of short distances can be read as a sustainable model of territorial development because it combines the notion of efficiency with the notion of resilience. The issue of transport and mobility of people from the perspective of slow mobility (in particular tramway, tram-train and TER) is considered as a vital energy resource of a metropolitan development system that places short distances, intermodality and density (around stations) at the heart of the system. This hypothesis introduces and underlines the importance of the relationship between energy and territorial projects. In this sense, the multidisciplinary research team of the project has tried to show how the intelligibility of the system related to short-distance energy must be found, not only in the system itself (transport, infrastructure and rail mobility in its main components) but also in its relationship with the environment (geographical, topological, social, etc.).