Human-centered simulation of intersection lighting: a parametric study of design tradeoffs

Pedestrian safety in urban environments remains a critical public health issue, with nighttime conditions substantially increasing crash risk for vulnerable road users. Yet intersection lighting design remains constrained by roadway-centric standards and static workflows, offering limited support for evaluating tradeoffs among multidirectional pedestrian visibility, glare, and light trespass—and environmentally sensitive designs are often presumed, without evidence, to compromise safety. We introduce SALUSLux, an open-source, programmable simulation toolkit for pedestrian-centered intersection lighting analysis, and apply it to a parametric study of 2,304 configurations on a standard four-way intersection. Results reveal three findings with direct implications for practice and standards. First, spatial geometry and luminaire properties interact so strongly that they cannot be optimized independently—a luminaire that performs well in one configuration can fail in another, making joint design-space exploration essential. Second, semi-cylindrical illuminance was the most difficult metric to satisfy across all scenarios and should be elevated to a required standard for intersection crosswalks; horizontal illuminance—the dominant metric in current practice—provided little additional information once other criteria were met, and overreliance on it risks encouraging excessive lighting that increases glare without improving pedestrian safety. Third, warm-color 2,700K lighting fully satisfies all pedestrian visibility thresholds when paired with appropriate spatial configuration, directly contradicting the assumed safety-sustainability tradeoff. Together, these findings provide an evidence base for intersection-specific lighting criteria that existing tools cannot deliver.