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Article

Investigating Traffic Pattern Effects of Variable Speed Limit System under Adverse Weather Conditions

악천후 기상 조건에서 가변형 속도제한 시스템의 교통 패턴 효과 분석 연구

Songha LEE1
,
Juneyoung PARK2*
,
Chunho YEOM3
,
Hyunjin PARK4
이 송하1
,
박 준영2*
,
염 춘호3
,
박 현진4
1The Ph.D. Course, Smart City Engineering, Hanyang University, Gyeonggi 15588, Korea
2Associate Professor, Department of Transportation & Logistics Engineering, Smart City Engineering, Hanyang University, Gyeonggi 15588, Korea
3Associate Professor, International School of Urban Sciences, University of Seoul, Seoul 02504, Korea
4Deputy Principal Researcher, Korea Expressway Corporation Research Institute, Gyeonggi 18489, Korea
1한양대학교 스마트시티공학과 석박사통합과정
2한양대학교 교통·물류공학과, 스마트시티공학과 부교수
3서울시립대학교 국제도시과학대학원 부교수
4한국도로공사 도로교통연구원 책임연구원
*Corresponding Author
30 June 2025. pp. 372-385
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Abstract

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.

Keywords
adverse weather
clustering
distance halo effect
driver compliance
variable speed limit

능동적 교통 관리 전략 중 하나인, 가변형 속도제한(VSL, Variable Speed Limit) 시스템은 기하구조, 교통. 기상 조건에 따라 고속도로 구간의 속도 제한을 조정하고 상/하류부 속도 차이 감소를 유도함으로써, 후미추돌 개연성을 감소시킨다. 정상적인 기상 조건과 다르게 운전자의 부적절한 속도 선택을 야기할 수 있는 악천후 기상 조건에서 VSL 시스템 적용은 교통안전의 효과를 향상할 수 있을 것으로 기대한다. 하지만, 대부분의 기존 연구는 실제 교통 환경이 아닌 시뮬레이션 분석 환경을 활용하거나, VSL 시스템 운영에 따른 실 운전자의 주행행태 변화를 분석한 연구는 제한적이었다. 따라서, 본 연구는 국내 고속도로 VSL 시스템이 운영되는 도로구간을 대상으로, 동적 교통 데이터 기준 악천후 기상 조건별 VSL 시스템 운영에 따른 교통 특성 변화를 분석하였다. 이를 위해 VSL 시스템의 영향을 받는 도로구간의 공통적인 교통 특성을 고려하기 위해 비지도 학습인 K-means Clustering 알고리즘을 사용하였고, 식별된 영향권에 따라 VSL 시스템 운영 전/후의 주행행태 변화를 비교·분석하였다. 결과적으로, VSL 시스템 운영 구간 내 상류부, 중간부, 하류부 구간으로 영향 권역이 구분되었고, 구간별로 교통 특성의 차이를 포착하였다. 또한, VSL 시스템의 운영 효과를 평가하였을 때, VSL 시스템은 악천후 조건에서 제한속도 이하의 주행속도를 유지하고 차량 간 속도 차이가 감소를 식별하였다. 특히, VSL 시스템 운영 구간에 접근하는 차량에 의해 중간부보다 상류부의 속도 편차의 크기가 증가하는 결과가 나타났고, 이 부분에 대해 향후 속도 관리 전략 수립 시 단속 구간 상류부에 대한 세부적인 안전 성능을 고려할 필요가 있다. 그리고, 향후 효과적인 VSL 시스템 운영 시, 개시된 제한속도에 대한 속도 단속 프로그램뿐만 아니라 운전자들의 주행행태를 잠재적으로 교정할 수 있는 교통안전 관리전략이 수반되어야 한다. 이 연구의 결과는 악천후 기상 조건에서 고속도로를 관리 및 관련 관리전략 수립에 관한 기초적인 연구로써 지원될 것이다.

키워드
악천후 기상 조건
군집분석
거리 후광 효과
운전자 순응도
가변형 속도제한시스템
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Information
  • Publisher :Korean Society of Transportation
  • Publisher(Ko) :대한교통학회
  • Journal Title :Journal of Korean Society of Transportation
  • Journal Title(Ko) :대한교통학회지
  • Volume : 43
  • No :3
  • Pages :372-385
  • Received Date : 2025-01-24
  • Revised Date : 2025-03-05
  • Accepted Date : 2025-04-02
  • DOI :https://doi.org/10.7470/jkst.2025.43.3.372
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