The political price of superblocks. Electoral outcomes of sustainable transport interventions in Barcelona

Urban and transportation policies are increasingly recognized for their potential to mitigate climate change impacts and address transport externalities. Amidst efforts to shift modal preferences and reduce transport emissions, cities are turning to spatialbased policies, such as Superblocks, to reshape urban mobility. This research examines the electoral outcomes associated with the implementation of Superblocks in Barcelona, focusing on their impact on political support for Barcelona en Comú (BEC) during the local elections of 2015 and 2023. Utilizing a combination of adjusted difference-in-differences and propensity score matching methods, we assessed the public's electoral response to the Superblock initiative amidst a backdrop of declining city-wide support for BEC. Our findings reveal that Superblock areas demonstrated significantly stronger support for BEC, suggesting a political premium for the party responsible for these urban interventions. Specifically, electoral support in Superblock districts saw an increase of 10–14% compared to the rest of the city. This result highlights the potential of urban transformation policies to influence political preferences locally and potentially validate the use of local electoral data as a tool for evaluating public response to highly contested urban policies.