Safety Assessment and Improvement Strategies on the Chalong Rat Expressway Using iRAP Star Rating

Abstract

The Chalong Rat Expressway is a key expressway in Bangkok, connecting suburban areas to the city center over a distance of 28.2 kilometers, with an average daily traffic volume of 213,054 vehicles. According to statistics from the 2024 fiscal year, accidents have occurred frequently on the expressway, particularly rear-end collisions and crashes into barriers. Although the elevated structure is designed to meet engineering standards, certain sections fail to comply with iRAP safety standards. This study applies the iRAP Star Rating system to evaluate safety levels based on accident data and the physical characteristics of the road. It identifies high-risk areas and proposes improvements, such as installing additional guardrails, crash cushions, and speed limit signs. The study's findings are expected to effectively reduce accidents and enhance the long-term safety of the Chalong Rat Expressway.