What are the effects of wearable police cameras on perceptions of the police? In this study, we report causal estimates from a crossover randomized controlled trial in Uruguay on the effects of use of body-worn cameras by traffic police on the perceptions of legitimacy and satisfaction by drivers ticketed for traffic violations. We pay particular attention to the effects on procedural justice—that is, perceptions of the fairness of the interactions between officers and drivers—without neglecting other features of legitimacy (i.e., effectiveness, distributive justice, and lawfulness). With the exception of lawfulness, wearable surveillance apparatuses showed improvements across all dimensions of legitimacy compared to control conditions, with medium to large effect sizes. The overall satisfaction from the police-public interaction was significantly higher when officers used body-worn cameras. These findings suggest that wearable surveillance technology can lead to enhanced perceptions of legitimacy across multiple dimensions, not just increased efficiency, as well as the perceived overall quality of police-public interaction.