Inequitable access to open public space has been debated for decades in New York City, as a high-density context where much of the city’s land surface is taken up by streets dominated by motor vehicles. In 2008, a new era in the city’s public space provision began with the launch of the NYC Department of Transportation’s Plaza Program, focused on the creation of new pedestrian plazas fashioned from street space formerly dedicated to traffic. By 2017, the Program had expanded from one to over 70 plazas city-wide and continues to operate using a ‘tactical urbanism’ approach with temporary materials like paint and planters. Drawing on fieldwork conducted in 2019 (Smeds, Citation2021), this essay describes how citizens’ epistemologies surrounding Diversity Plaza in the Jackson Heights neighbourhood became a key driver for the reform of NYC’s Plaza Program towards greater public space equity. Based on this case, I argue that citizens’ struggles for epistemic justice can pave the way for realising greater distributive and procedural justice in transitions towards post-car cities.