DO Seminar Speakers: Giacomo Maggiorano and Léo Wursten Location: Anthropole 4059, Lausanne The 15-minute city has emerged as a prominent urban planning paradigm advocating that essential daily needs - such as employment, retail, education, healthcare, and leisure- be accessible within a 15-minute walk from any location in the urban area. While conceptually compelling, its effective implementation requires rigorous, data-driven tools capable of diagnosing accessibility gaps and evaluating potential interventions. In collaboration with SDOL (Stratégie et développement de l’Ouest lausannois), the authority coordinating urban development across the municipalities of Western Lausanne, we develop a quantitative diagnostic of the current situation. Our approach relies on the construction of a pedestrian accessibility model based on OpenStreetMap data (pedestrian network and points of interest) combined with detailed population and employment data provided by SDOL. The territory under study is characterized by significant spatial fragmentation due to natural barriers and major transport infrastructure, which constrain walkability and generate structural inequalities in service access. Using this integrated dataset, we compute accessibility indicators, identify critical services with limited coverage, and detect underserved population clusters. Beyond this diagnostic phase, we analyze selected structural interventions - such as the addition of a new pedestrian bridge - and assess their impact on network connectivity and accessibility levels. This analysis enables a quantitative evaluation of how targeted infrastructure investments may reduce proximity gaps and improve spatial equity. It also opens the door to optimisation-driven investment strategies grounded in quantitative accessibility analysis.
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