Evaluation of administrative division-level road safety indices

Inadequate regional road safety studies have been conducted in developing countries such as Iran, Egypt, and Türkiye. Also, despite the existence of various regional road safety indices (RSIs), the associations between these rates rarely have been studied. Besides, there are limited studies regarding crash severity indices in the literature. Despite high road fatalities in developing countries, little attention has been given to road safety performance in these countries. Additionally, the differences between developed and developing countries regarding road safety performance rarely have been discussed. Thus, it was aimed to evaluate the regional RSIs in Iran, Türkiye, the UK, Egypt, and the USA, using correlation and regression analysis. Also, the distribution patterns of administrative divisions of these countries were assessed. Data on regional road safety and socioeconomic rates of these countries were collected. The associations between the variables were evaluated using correlation and regression analysis. Using Moran's I, local Moran indices, and Jenks natural breaks method, administrative division's spatial distributions were evaluated. Hot spot analysis was used to identify road safety deficient regions. Significant correlations between the variables were detected. Vast local clusters in terms of RSIs were detected in the countries. The distribution patterns of subdivisions regarding RSIs were cluster-like. Variable groups influencing road safety performance in regions were identified. Generally, crashes were severe in underdeveloped and remote regions. Increasing income and education levels make it possible to reduce crash severity indices in these countries. Higher exposure rates mean higher fatalities in regions. There is a nonlinear and significant association between motorization rates and TR indices of regions, and fatality risk decreases as the motorization rate increases. There is a considerable gap between developed and developing countries regarding regional RSIs. Findings suggest using the fatality per number of motor vehicles index instead of the fatality per population rates in regional road safety studies. Using distinct exposure measures in calculating RSIs leads to the inverse local cluster maps.