Differences in pedestrian injury severities between contrasting and non-contrasting attire in nighttime crashes: a...

Pedestrian crashes during nighttime hours pose a significant safety challenge, with reduced visibility being a key contributing factor in injury severity. Despite its importance, the role of pedestrian attire visibility, specifically contrasting versus non-contrasting clothing, has received limited empirical attention in real-world crash settings. To address this gap, we apply a partially constrained temporal random parameters logit model with heterogeneity in means, the first application of this framework to assess pedestrian attire visibility and nighttime injury outcomes. Using six years of police-reported data from Chicago (2018-2023), stratified into pre-, during-, and post-COVID periods, likelihood ratio tests confirmed significant temporal instability, supporting the proposed framework. Out-of-sample prediction experiments were conducted to estimate how outcomes might differ if pedestrians in non-contrasting attire had instead worn contrasting clothing. Findings show that pedestrians in non-contrasting attire face higher probabilities of severe injury, especially after COVID, with older pedestrians disproportionately affected. Contrasting attire mitigates much of this risk in dark, unlit conditions, underscoring the importance of conspicuity. Additional results indicate elevated risks associated with pedestrians disregarding traffic control devices, in-roadway walking, and driver failure to reduce speed, whereas protective effects are observed in marked crosswalks, under lower speed limits, and in crashes involving female drivers. Out-of-sample predictions further suggest that reassigning contrasting attire would substantially lower the likelihood of severe injuries. While attire visibility matters, the results underscore the need for systemic interventions, improved roadway lighting, traffic calming, and strengthened driver responsibility, with visibility promotion positioned as a complementary measure rather than a substitute for infrastructure and enforcement.