輕軌優先號誌時制補償方法之研究

Abstract

完善的都市軌道運輸系統除了能達到疏運交通的功能，也能帶動周邊都市發展，政府於民國106年積極推動前瞻基礎建設計畫，軌道建設便是其中重要的一環，因此軌道系統的設計與規劃成了現代化都市需面對的重大課題。 不同於鐵路及捷運系統，輕軌系統為B型路權，與一般車輛共享路權。為了使輕軌能夠順暢通過路口，會於平面交叉口實施輕軌號誌優先策略，目前國內系統主要實施綠燈延長、紅燈縮短等優先策略，增加輕軌方向時相秒數以利輕軌通過，然而實施優先號誌控制策略的同時，將壓縮到非輕軌時相的綠燈時間。因此，為了減少輕軌系統對一般道路車流造成的影響，優先號誌的實施會伴隨時制補償策略，使週期回復或是補償非輕軌時相損失的秒數。在過去的案例中，並沒有特別針對時制補償進行設計，多以簡易的方式補償，以淡海、安坑輕軌為例，淡海輕軌的時制補償方式是將週期回復，而安坑則是利用改變下一時相秒數的方式將時制回復到時間基準點。 若補償之秒數未能因應該路口之交通量，路口績效將會受到影響，因此本研究希望改善安坑輕軌的補償方式，透過VISSIM模擬不同交通量狀況下，非輕軌方向所需之補償秒數，並以「平均人延滯」作為評估指標，接著進一步分析其他可能影響補償秒數的因素，如班距、週期等，歸納出決定時制補償秒數的準則，並比較模擬結果與其他補償方法的差異。 模擬結果顯示本研究建立之時制補償方法可模擬出不同情境下之最佳補償秒數值，並且能夠將因實施優先號誌策略造成的時間偏離在兩週期內回復。此外，此方法可在不影響輕軌績效的狀況下改善支道延滯，且也有助於整體路網績效之提升。進一步模擬不同週期與班距造成之變化，可發現當週期在一定範圍內時，本研究所使用的最佳補償秒數求解法能夠有效找到最佳時相長度比例以及適合的時制補償秒數，但班距與時制補償則較無顯著的關聯性。

A mature urban rail transit system can not only provide the service of transportation, but also promote the development of surrounding cities. Recently, the government actively promoted the prospective infrastructure plan. Railway construction plays an important role of it. Therefore, the plan of the railway system has become a major issue for modern cities. Unlike the railway and MRT system, the LRT system is B-type right-of-way, which move on the road with the general vehicle. In order to make the LRT pass smoothly through the intersection, the transit priority strategy (TSP) will be implemented at the intersection. At present, the priority strategies the domestic systems mainly implement are “Green Extension” and “Red truncation,” which increase the phase time of the LRT to make the LRT pass the intersection effectively. At the same time, the green time of the non-LRT phase will be compressed. In order to mitigate this impact, the signal compensation method will be used to recovery the cycle and compensate the time loss. In the past cases, there was no specific rule for signal compensation method, and most of them were compensated in an incomplete way. If the signal compensation fails to meet the traffic demand, the intersection performance will be affected. Therefore, this study hopes to improve the signal compensation method of the Ankeng light rail. The main goal is using VISSIM to simulate the best signal compensation seconds required for the non-LRT direction in different traffic conditions. And the 'average person’s delay' will be the evaluation index. Then, the study will analyze other factors that may affect the compensation, such as headway, cycle time, etc. Finally the study will summarize the criteria for determining the seconds to compensate and compare the simulation results with other signal compensation methods. The simulation result shows that the signal compensation method can find the optimal compensation value in different situations and can recover the time deviation caused by the implementation of the priority strategy. In addition, this method can improve the delay of the lateral aisle without affecting the performance of the LRT and also improve the overall performance. Further simulation shows that when the cycle time is within a certain range, the signal compensation method used in this study can effectively find the optimal phase length ratio and the suitable compensation length. However, there is no significant correlation between headway and the signal compensation.