Defense Alexandra Georgescu

The four-year project, jointly funded by the DSI and the GIS group and embedded in the SISAL: Situation-Aware Individualised Spatial Accessibility Analytics project led by Dr. Hoda Allahbakhshi, investigated how small, everyday sidewalk features in urban environments, such as kerbs, stairs, or cobblestones, shape who can actually get around a city and who cannot. Urban areas are usually assessed for accessibility using simple measures such as walking distance or travel time, but these overlook a key fact: the same kerb that is a minor inconvenience for one person can be a complete barrier for someone using a wheelchair, while a feature that helps a visually impaired person navigate safely can be an obstacle for someone pushing a stroller. Using Zurich's Old Town and city centre as a case study, the thesis combines a large survey of people with different mobility restrictions with detailed, sidewalk-level data on thousands of physical barriers and facilitators, to build an accessibility model of the city that reflects how different people actually experience it.

The results show that these microscale sidewalk-level features add up to substantial, measurable inequalities: individuals may have to take lengthy detours to find an accessible route, or can be left with "islands of inaccessibility", parts of the city that remain fully reachable for some, but entirely unreachable by a barrier-free route for others. The thesis provides a framework to combine real perception data from affected groups with fine-grained accessibility data, allowing researchers and planners to quantify accessibility disparities and pinpoint exactly which features are creating the most inequality, prioritising fixes where they matter most, work with direct relevance for making cities more inclusive as urban populations age and grow.