Despite its high population density and public transport connections, cars make out 65 % of the modal share in Flanders, Belgium. Flemish car use is still increasing, despite the necessity to decrease car use for reasons linked to the environment, health, and infrastructural problems. Due to historical auto-centric policymaking, car dependency -both physically and mentally- has become ingrained in mobility behavior. To experiment with how car dependency can be diminished, the campaign ‘30 Dagen Minder Wagen’ (30 Days with Less Cars) was launched, which challenged Flemish people to not use their cars as much as possible during July 2022. 6500 people participated, with a resulting CO2 emission decrease equal to the annual emissions of 64 cars. This was the first large-scale academic campaign oriented on mobility behavioral change in the region.