Human-centric digital twins: A contradictio-in-terminis or a useful tool to plan the cycling city?

Digital twins are virtual representations of physical systems. They originated as a way to anticipate rocket engine failure. Recently they became popular in urban planning, as a realistic digital model of a city, fed by sensory data and informing decision making. Many promises have been made, painting a futuristic picture of a “smart city brain” that automatically senses and steers its dynamic processes. Those promises have remained largely empty and the urban digital twin is struggling to move past the stage of a mere hype technology. Cities are not rocket engines, and they don’t satisfy our equations. They are complex systems made out of people, in which a myriad of social and economical processes are taking place, bringing along diversity, chaos, and unpredictability. These are characteristics of cities that bring them to life, rather than unwanted noise complicating our models. However, when hype technologies move forward, and we begin to be honest about their limitations, they can turn into a tool of practical use. A shift towards a human-centric perspective on urban digital twins is increasingly promoted, in which the technology serves actual human needs, rather than vice versa. In which human involvement in the digital processes is seen as a strength rather than a limitation. And in which blackbox algorithms are replaced by transparent and explainable models, adaptable to a local context.