Comparative Assessment of Crash Injury Outcomes for Older Drivers in Older and Newer Vehicles

Abstract

The growing population of older drivers and the continued use of aging vehicles present increasing challenges to road safety. Older drivers, due to age-related declines in cognitive, visual, and motor abilities, are more susceptible to severe injuries in crashes. Simultaneously, older vehicles often lack modern safety features, exacerbating injury risks during severe collisions. This study investigates the combined effects of driver age and vehicle age on injury severity in single-vehicle crashes involving older drivers. Specifically, it analyzes how driver characteristics, vehicle attributes, environmental conditions, and crash dynamics influence injury outcomes when older drivers operate older versus newer vehicles. Crash data spanning 2020–2024 were obtained from Alabama’s Critical Analysis Reporting Environment system. Two datasets were developed: crashes involving older drivers in older vehicles (manufactured before 2006) and in newer vehicles (manufactured after 2017). Injury severity was categorized as major, minor, or no injury. To account for unobserved heterogeneity, a random parameters multinomial logit model with heterogeneity in means was employed. The results reveal significant differences in injury severity determinants between older and newer vehicles. Nonuse of seatbelts, vehicle rollovers, and collisions with trees were strongly associated with higher probabilities of major injuries across both groups. However, older vehicles exhibited greater vulnerability, with older drivers more likely to sustain major injuries compared to when driving newer vehicles. Environmental factors such as dark, unlit conditions and rainy weather influenced injury probabilities differently across vehicle age groups, suggesting adaptive behavior among older drivers. Crashes in residential areas and those involving pickup trucks or SUVs were associated with lower injury severity. These findings highlight the critical interaction between driver and vehicle aging in crash outcomes. The results underscore the need for targeted interventions, including promoting seatbelt use, encouraging the retirement of older vehicles, and designing safety policies tailored to older drivers.