Composite Assessment of Traffic Accident Risk in Safety Management Units: A Case Study on the Ranking of Iran’s Provinces

Road safety and accident reduction remain among the most critical transportation challenges worldwide. A comprehensive analysis of accident risk and an evaluation of the safety performance of safety management units play a crucial role in the formulation of safety policies and the effective allocation of resources. The objective of this study is to identify relevant risk indicators and develop a composite index for the comprehensive assessment of accident risk across safety management units. Iran’s provinces were selected as the case study. In this research, risk indicators were categorized into three main groups: general risk, traffic risk, and road risk. The indicators were evaluated based on available data, and the provincial Composite Risk Index (CRI) was calculated using the mean values of the three indicator categories. The standard deviation of the indicators was analyzed to assess the stability and homogeneity of the risk conditions within each province. The results indicate significant variation in CRI values across provinces. Provinces such as Markazi was classified as high-risk, whereas Khuzestan was categorized as low-risk. Furthermore, the analysis of standard deviation revealed considerable variability in certain provinces, including Tehran and Sistan-Baluchestan, highlighting the importance of accounting for data dispersion in risk analysis and decision-making processes. The methodological framework proposed in this study, along with the application of the CRI composite index, provides a robust tool for ranking and comparing management units. It can serve as a foundation for prioritizing preventive interventions and optimizing the allocation of limited resources in the pursuit of improved road safety.