악천후 기상 조건에서 가변형 속도제한 시스템의 교통 패턴 효과 분석 연구

초록

Variable speed ​limit system (VSL), one of the active traffic management strategies, has modified the speed limit at expressway, and reduces likelihood of rear-end collisions by inducing a decrease in the speed difference between upstream and downstream sections. The implementation of a VSL system under adverse weather conditions, which often lead drivers to select inappropriate speeds compared to normal conditions, is anticipated to enhance traffic safety and its overall effectiveness. However, previous studies have utilized simulation program rather than real traffic environments, or studies analyzing changes in real drivers’ driving behavior due to the operation of the VSL system have been limited. As such, this paper has analyzed changes in traffic characteristics resulting from the operation of a VSL system under adverse weather conditions, using dynamic traffic data collected from road sections equipped with the system on domestic expressways. K-means Clustering algorithm, an unsupervised learning algorithm, was employed to consider common a traffic characteristics affected by the system. Changes in driving behavior before/ after the operation of the system were then compared and analyzed based on the identified impact area. As a result, the areas were divided into upstream, middle, and downstream sections within the system operation section, and the differences in traffic characteristics were captured by section. Also, when evaluating the operational effect of the VSL system, it was identified that the system maintained a driving speed below the speed limit under adverse weather conditions and that the speed difference between vehicles decreased. Notably, the results indicated that the speed variance upstream of the system increased compared to the middle section, due to vehicles approaching the VSL operation section. Furthermore, for the effective future operation of the system, it is essential to implement not only speed enforcement programs for the posted speed limits but also traffic safety management strategies aimed at potentially correcting drivers’ driving behaviors. The findings of this study will serve as foundational research to support expressway management and the development of related management strategies under adverse weather conditions.

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