Disparities in Pedestrian and Cyclist Crashes by Social Vulnerability Across South Carolina

Background: Little crash equity research has controlled for active transportation rates, examined the Southeastern United States, or used composite sociodemographic metrics. This study analyzed disparities in pedestrian and cyclist crashes and crash severity according to level of social vulnerability (SV) across South Carolina. Methods: Data about SV and its 4 dimensions (socioeconomic status, household composition and disability, minority status and language, and housing type and transportation) were compiled for all census tracts (N = 1103) within South Carolina. Data for all crashes involving a pedestrian (n = 10,688) and/or cyclist (n = 4802) from 2011 to 2021 were obtained from the South Carolina Department of Transportation and geocoded to the respective census tract. Total average pedestrian and cyclist crash severity (Equivalent Property Damage Only) were also calculated for each tract. Crash frequency and severity scores were adjusted using the average number of walking and cycling trips in the census tract per year using StreetLight Data. Mixed-model linear regression analyzed the relationships between overall SV and the 4 SV dimensions and 4 crash measures—pedestrian and cyclist frequency and severity. Stratified analyses were conducted for urban and rural tracts. Results: Overall SV was positively and significantly associated with all 4 crash outcomes in urban areas: pedestrian crashes per trip (B = 0.048, SE = 0.012, P < .001), pedestrian crash severity per trip (B = 9.018, SE = 2.516, P < .001), cyclist crashes per trip (B = 0.093, SE = 0.029, P < .01), and cyclist crash severity per trip (B = 16.370, SE = 5.482, P < .01). In urban areas, greater SV was associated with more severe pedestrian and cyclist crash outcomes. Conclusions: Targeted policy and programmatic and infrastructure interventions are needed to improve active transportation safety and public health.