The Hidden Costs of Private Mobility: Public Land Occupation and Inefficiency in Milan

Urban sustainability and climate change mitigation have underscored the necessity of transforming transportation systems toward more eco-friendly solutions. Private vehicles contribute significantly to greenhouse gas emissions and occupy substantial urban space when not in use. This study examines the actual usage patterns of privately owned cars in Milan, Italy, to quantify their temporal and spatial occupation of public land. Leveraging an extensive dataset collected from black box devices installed in over 100,000 vehicles registered in the Milan province, approximately 100 million trips in 2022 were analyzed. The analysis reveals that the vast majority of private vehicles are inactive for over 90 % of the time, with 98.7 % of cars being used for less than 10 % of the observed time. The spatial analysis, conducted using OpenStreetMap, indicates that 75.2 % of parking events occur on public streets, highlighting significant occupation of urban land. These results emphasize the inefficiency of private cars in urban environments, where vehicles predominantly occupy valuable public space without being utilized. The study suggests that transitioning to shared autonomous vehicles could substantially reduce the number of private cars, enabling cities like Milan to reclaim public spaces for urban regeneration projects, infrastructure improvements, and green areas. This structural change has the potential to enhance environmental sustainability, reduce emissions, and improve the quality of urban life. Future research should focus on developing strategies for implementing shared autonomous mobility solutions and planning for the reallocation of reclaimed urban spaces.