KOREASCHOLAR

This study aimed to evaluate the effect of key operational factors on traffic performance in long underground expressways. This study was motivated by the increasing policy interest in underground expressway infrastructure as a solution to chronic surface-level congestion in dense urban regions. A scenario-based microscopic traffic simulation was conducted using VISSIM considering combinations of traffic volume, proportion of heavy vehicles, and longitudinal slopes. A total of 72 scenarios were simulated, and the weighted average speed and total throughput were analyzed. The simulation results showed that the entry traffic volume and longitudinal gradient significantly affected the average speed, particularly in uphill exit segments. The heavy vehicle ratio also contributed to consistent reductions in speed. However, the overall throughput remained relatively stable despite variations in heavy vehicle proportions, suggesting that speed is more sensitive to flow composition than to volume capacity. Although interaction effects were not statistically tested, the combined scenario trends suggested that steeper slopes and high heavy-vehicle ratios jointly intensify speed reduction. These findings support the early-stage design and traffic planning of underground expressways.

ABSTRACT
1. 서론
2. 기존 문헌 고찰
3. 연구 수행 방법
    3.1. 분석 개요
    3.2. 시뮬레이션 입력변수 설정
4. 시뮬레이션 결과
    4.1. 결과값 전처리 및 정리
    4.2. 시나리오별 시뮬레이션 결과
5. 통계분석
    5.1. Spearman 순위 상관분석
    5.2. Kruskal-Wallis H-test
6. 결론
감사의 글
REFERENCES

• 양충헌(한국건설기술연구원 도로교통연구본부 연구위원) | Yang Choong Heon Corresponding author
• 윤천주(한국건설기술연구원 도로교통연구본부 수석연구원) | Yoon Chun Joo
• 고상운((주)내일이엔시 도로교통안전연구소 연구원) | Ko Sang Woon
• 이진각((주)내일이엔시 도로교통안전연구소 소장) | Lee Jin Kak