Unobserved heterogeneity and the effects of driver nationality on crash injury severities in Saudi Arabia

This paper investigates factors that significantly contribute to the injury severity of different drivers of different nationality backgrounds. Using the data from Riyadh, Saudi Arabia, a random parameters multinomial logit model of driver-injury severity was estimated to explore the effects of a wide range of variables on driver injury-severity outcomes. With three possible outcomes (no injury, injury, fatality), only single-vehicle crashes are considered and crashes involving domestic (Saudi) and international (non-Saudi) drivers were modeled separately. Model estimation results show that a wide range factors significantly affect the injury severity outcomes in single-vehicle crashes including driver attributes (such as nationality and age), vehicle characteristics (such as make, model and year of manufacture), driver actions (such as speeding and preoccupation on driving), and other factors (such as location and time of the accident); and that the influence that these variables have on injury-severity probabilities vary considerably between Saudi and non-Saudi drivers. While Saudi Arabia is rather unique because of the large numbers of non-national drivers, the results suggest that different nationalities, with their different cultural, educational and, behavioral backgrounds, may affect risk-taking behavior and resulting crash-injury severities.