Analysis of Risk Factors Affecting Size and Severity of Traffic Crashes in Riyadh, Saudi Arabia

Recently, growing concern has been shifting towards traffic safety in the kingdom of Saudi Arabia (KSA). KSA has a unique situation regarding traffic safety problems. KSA can be classified as one of the developed countries in terms of the magnitude and quality of the road network available and compatible with international standards. However, it can also be considered as one of the developing countries as the rate of increase in the number of road crashes in the KSA is substantial compared with the relevant figures of other developing countries and other countries of the Gulf region and hence, more research efforts are still needed. This paper aims at better examining the nature and causes of fatal and serious traffic crashes in KSA so that remedies and/or future studies could be suggested. For this purpose, data from 11545 reported fatal and injury traffic crashes that have occurred in Riyadh (the capital of KSA), during the period 2004-2011, were used in the analysis. A logistic regression model was estimated and the results revealed that crash reason (over-speeding), damages in public property, day of the week, crash location (non-intersection location), and point of collision (head-on) were the significant variables affecting the binary target variable (fatal and non-fatal crashes). In addition, the structural equation modeling approach was developed to identify and quantify the impacts of significant variables influencing crash size (e.g., number of injuries, number of vehicles involved in the crash), one of the important indices that measure the level of safety of transportation facilities. The results showed that road factor was the most significant factor affecting the size of crash followed by the driver and environment factors. Moreover, a comparison between the characteristics of the Saudi severe crashes and a sample of US severe crashes (as an example of a developed country) are also provided and discussed. The results highlight the need for country specific countermeasures to safety problems.