고속도로 터널 내 차로변경에 따른 교통류 특성 분석 연구

Abstract

The number of domestic tunnels are continuously increasing every year because of the topographic characteristics that seventy percent of Korean territory is covered with mountains and tunnel length is also getting longer. Since lane changes in tunnels are not permitted in principle, high-speed following vehicles must follow low-speed leading vehicles and for this reason the capacity and speed reductions in tunnel could be occur frequently. Because such influences are likely to amplify as the tunnel length gets longer, it is necessary to evaluate whether the prohibition of lane change in tunnel would continue or not. Therefore, this study was conducted with a purpose to establish the improvement of the existing regulation that prohibits lane change by performing the effectiveness analysis in case lane change is permitted in freeway tunnels. Simulation analysis was undertaken to determine whether lane changes in tunnels should be restricted using various scenarios composed of a variety of tunnel lengths, number of lanes, vehicle composition, and level of service. The measure of effectiveness used in this study was average travel speeds, average delays, and densities. The results showed that travel speed increased in all scenarios when lane changes were permitted and even showed greater speed increases for mixed traffic including heavy vehicles. At the low level of service, the increase in travel speed begins to grow as the tunnel length gets longer, while the increase of travel speed shows similarity regardless of tunnel length at the high level of service. In comparison with the number of lanes at the same tunnel length and LOS, it was shown that the increase in travel speed appeared to slightly increase the more lanes there were, due to the flow having more chances to change lanes on multi-lane freeways. It is summarized that lane changes in tunnels may be allowable as the tunnel length gets longer and the number of lanes increases.