Understanding the expected safety performance of rural signalized intersections is critical for: 1) identifying hotspot sites that deviate substantially from their expected safety performance; 2) understanding influentialfactors associated with crashes; and 3) serving as a benchmark for futureperformance of sites, i.e. safety planning activities. These three critical activities are routinely conducted for safety management and planning purposes in jurisdictions throughout the US and world, and thus knowledge of the underlying expected safety performance is critical. This paper aims to develop baseline expected safety performance of rural signalized intersections in South Korea, which to date have not yet been established or reported in the literature. Examined are data from numerous locations within Korea for both 3-legged and 4-legged configurations. Also examined are thesafety effects of a host of operations and geometric variables on the safety performance of these sites. In addition to establishing the safety performance of Korean rural signalized intersections, supplementary tables and graphs are developed for comparing the baseline safety performance of sites with various geometric and operational features. These graphs illustrate the expected performance of sites and clearly identify the associationsof various factors with safety. The expected safety prediction tables offer advantages over the regression prediction equations by allowing the safety manager to isolate specific features and examine their impact on expected safety. The examination of the expected safety performance tables through illustrated examples serve to highlight the need to correct for regression-to-the-mean effects, emphasize the negative impacts of multi-collinearity and why multivariate models do not translate well to accident modification factors, and illuminate the need to examine road safety very carefully and methodically. Caveats are provided on the use of the prediction graphs developed in this paper.
Abstract