Factors Affecting Crash Likelihood of Motorcycle Entering a Roundabout

Abstract

Roundabouts are one of the most effective and widely used intersection controls in developed nations. Concerns have been raised, however, about the safety of motorcyclists using roundabouts in Thailand, especially when entering and exiting the roundabout. This research, therefore, aimed to examine the factors that affect the crash likelihood of motorcycles entering roundabouts. This study observed 4 roundabouts located at Khon Kaen University. Their inscribed diameters ranged from 35 meters to 50 meters. UAVs were used to video traffic characteristics. During post-recording analysis, 785 interaction events were observed. The characteristics of the motorcycle and the other vehicle, as well as the post-encroachment time (PET), were extracted for each interaction. Using the technique of multiple linear regression, the PET, which is used to describe the crash likelihood, was modeled to identify their contributing factors. The results showed that the characteristics of motorcyclists, the characteristics of interaction events, and the geometry of roundabouts have a significant impact on crash risks. Failure to yield to vehicles inside the roundabout, the yielding behavior within a circulatory roadway, an increase in speed of entering motorcycles, and the involvement of motorcycles in the conflict, were factors that increased crash likelihood. In addition, this study discovered that the likelihood of a collision increases as the radius of deflection increases. Ultimately, the results of this research highlight the variables influencing the risk of collision for motorcyclists entering roundabouts, which should be prioritized in terms of safety.