Roadway features associated with elderly drivers in motor vehicle crashes

BACKGROUND As the number of older US drivers has increased over the past decades, so has the number of injuries, hospitalizations, and deaths from motor vehicle crashes (MVCs) involving elderly drivers. We seek to identify personal, environmental, and roadway features associated with increased crashes involving elderly drivers. We hypothesize that elderly drivers are more likely to be involved in MVCs at intersections with more complex signage and traffic flow. METHODS This is a retrospective observational study using 2015 to 2019 police traffic crash reports and a Department of Public Health database of built-environment variables from a single urban center. Demographics and environmental/road features were compared for vehicle-only MVCs involving elderly (>= 65 years) and younger drivers. chi(2) and nonparametric tests were used to analyze 36,168 drivers involved in MVCs. RESULTS There were 2,575 (7.1%) elderly drivers involved in MVCs during the study period. Left turns and all-way stop signs were associated with increased crash risk among elderly drivers compared with younger drivers. Elderly-involved MVCs were less likely to occur at intersections with left-turn restrictions, traffic lights, only one-way streets, and bike lanes compared with MVCs with younger drivers. Elderly drivers were more likely to be involved in MVCs on weekdays, less often intoxicated at the time of the crash, and less frequently involved in fatal MVCs compared with younger drivers. However, elderly drivers were more frequently the at-fault party, especially after the age of 75 years. CONCLUSION Updates to roadway features have potential to decrease injury and death from MVCs involving elderly adults. Left turn restrictions or other innovative safety treatments at all-way stops or where left turns are permitted may mitigate road crashes involving older adults. Education may increase awareness of higher-risk driving tasks such as turning left, and driving alternatives including public transportation/paratransit may offer alternate means to maintain activities of daily living.