Investigating Geometric Design Characteristics and Crash Rates of Roundabouts in Thailand

This research investigates the correlation between the geometric design characteristics of roundabouts (RABs) and crash rates in Thailand, aiming to uncover design-related patterns and causes of traffic crashes at RABs. Through Geographic Information Systems (GIS), the study analyzed crash data and geometric configurations of 2108 RABs across Thailand, classifying them by type, size, and roadway attributes. Preliminary analysis reveals that single-lane RABs accounted for 28 crashes with four fatalities and 13 injuries, while multi-lane RABs saw 30 crashes, resulting in 3 fatalities and 13 injuries. The logistic regression model identified critical geometric features impacting crash likelihood; notably, the number of entry lanes significantly affects crash rates, with wider circular lanes increasing risk. These findings underscore the importance of adhering to and refining design standards to enhance road safety. By pinpointing specific design elements that correlate with higher crash risks, the study provides a foundation for developing targeted interventions, contributing not only to traffic safety improvements in Thailand but also offers valuable insights for the enhancement of RAB safety globally.