Determination of black spots by using accident equivalent number and upper control limit on rural roads of Thailand

Abstract

The Department of Rural Roads (DRR) is one of the highway authorities in Thailand responsible for over 48 000 kilometres of rural roads and highway networks. One of its responsibilities is to provide better road safety management. In road safety procedures, black spots are usually identified by observing the frequency of accidents at a particular road section. This research aims to develop a model that includes levels of accident severity in the black spot identification process. The classification of severity levels includes fatalities, serious injuries, minor injuries, and damaged property only. The Analytic Hierarchy Process (AHP) is employed to derive the weight of each severity level. The identification model is developed using Equivalent Accident Number (EAN) and Upper Control Limit (UCL). The data applied in the model are obtained from the road accident investigation of DRR. Five roads — Nakhon Ratchasima 3052, Chonburi 1032, Nonthaburi 3021, Samutprakarn 2001 and Chiangmai 3029 — have been selected based on the top frequency accident recorded in the last three years. Based on the results of black spots identified in the study, most accidents occurred from frontal and rear-ended impacts due to exceeded speed limits. The article discusses recommendations.

Identifying High Crash Signalized Intersections and Application of Highway Safety Manual Predictive Method to Reduce Crashes

“…In this study CMFs for some of the treatments that are available in the HSM and were used to identify their effects. However, for some others, the CMF is not offered nonetheless a trend about the possible change in crashes or human behavior is identified [9]. Treatments that were used are categorized into four categories; treatments related to intersection types, treatments related to intersection design elements, treatments associated to traffic control and operational elements of intersections and treatments associated to access management.…”

“…For this model the authors collected the crash data from five rural roads in Thailand during three years. The results showed that most crashes were rear-end type due to exceeded speed limits based on the results of black spots recognized in the study [9]. Erdogan et al (2008) conducted a study in Turkey to assess crash distribution in a highway in Afyonkarashiasar city.…”