This report provides insights from different fields – mobility planning, urban planning, and sociology – on how to combine social sciences and engineering sciences to achieve a shift towards sustainable mobility, liveable neighbourhoods, and urban health and well-being. At the core of these three goals is what we call “shared speed” – a planning and design strategy that aims to make the city’s various modes of transport, from driving to walking, more equal. By adapting speed levels through design and technology in urban streets, we will not only have lower emissions, fewer accidents, and less stress, but urban planners and architects will be forced to think in new ways: such as the "15-minute city", a concept that brings people and services closer together. They must think about proximity, about redesigning street spaces for more social encounters and engagement, and to enable all citizens to feel confident in using the space.