Exploring contributing factors in single-vehicle truck crashes on rural roads: Accounting for unobserved heterogeneity and role of solar glare

This study investigates the factors that influence single-vehicle large truck crashes on rural roadways using Highway Safety Information System data from the state of Washington from 2014 to 2018. We used a random parameter multinomial logit model with heterogeneity in means and variances to identify significant random parameters, interactions, and factors exhibiting heterogeneity in means. Additionally, a comprehensive process was used to determine which crashes were impacted by solar glare. Two parameters, including driver age over 50 and the absence of airbags in vehicles, were found to be significant random parameters. Results revealed that solar glare effects notably influenced possible injury and nondisabling injuries in single-vehicle truck accidents. Further, factors like collector roads, curved segments, lack of access control, driving without safety restraints, operating defective vehicles, skidding, overturning, and the second quarter of the year increase the likelihood of disabling/fatal injury. The study’s insights enrich the limited literature on single-vehicle large truck crashes on rural roads, enabling policymakers and transportation and logistics agencies to take appropriate safety measures in these areas. This research is crucial for promoting sustainable transportation by addressing the safety challenges associated with large truck operations on rural roads. It can help prevent traffic injuries and improve overall road safety. Enhancing safety can reduce crash-related delays, economic losses, and environmental impacts caused by traffic congestion and vehicle emissions. Recommendations are suggested, including the use of transverse rumble strips and prior signboards to enhance driver alertness and combat driver drowsiness. Additionally, the use of metalized windshields in vehicles to mitigate glare-induced blindness can further improve safety.