Understanding the factors associated with severity of aging population-involved pedestrian crashes in Florida

When involved in a vehicle-pedestrian collision, aging pedestrians are prone to a higher injury severity risk due to their reduced physical and cognitive abilities, compared to younger pedestrians. The main objective of this study was to identify main factors associated with injury severity of aging pedestrians involved in pedestrian-vehicle crashes. A binary logistic model was developed using five-year (2009-2013) pedestrian crash dataset archived by the Florida Department of Transportation. The model described the relation between injury severity of aging pedestrians and various explanatory variables. Principal Component Analysis was used as a decision tool for selecting independent variables to include in the model. Further, predictive margins plots were used as a decision tool for converting some continuous variables to categorical variables. The following factors were found to significantly increase the injury severity of aging pedestrians; crash factors (alcohol involvement of driver/pedestrian, vehicle movement), geometric factors (higher maximum posted speed, presence of curve and up/down grade, non-curbed shoulders), and environmental factors (poor lighting conditions). Conversely, the increase in shoulder width resulted in lower injury severity. Understanding of key determinants that influence aging pedestrian injury severity may allow for the identification of measures to improve aging pedestrians walking environments on roadways, thus enhancing their operational and safety experience on the road. Based on the findings of this research, several countermeasures have been recommended. The proposed countermeasures take a holistic safety improvement strategy that encompasses all four E’s of highway safety, i.e., engineering, education, enforcement, and emergency services.