號誌週期長度比較分析之研究

Abstract

國內私有運具使用量逐年提高，因此各地交通量也持續上升，造成了許多路面交通衝擊與問題，例如在尖峰時段道路上經常發生壅塞現象，導致市區交通癱瘓。其中，市區路網是由多個幹道所組成，而幹道又是由許多個路口組成，紓解路口車流則必須仰賴交通號誌的運作，為使車輛有效且安全地通過路口，良好的號誌時制設計是重要關鍵。 本研究以台北市市區道路忠孝東路與仁愛路作為調查地點，探究目前號誌時制設計上之可改進之處，發現台北市之號誌週期長度在尖峰時段普遍超出國際規定之最佳週期長度範圍。雖然在長週期下，綠燈運行時主要幹道之車輛可連續通行多個路口，但綠燈關閉後車輛則必須花費較長之等待時間，可能造成路口延滯增加。因此，要如何在車輛續進與路口延滯之間取得平衡，並求得最佳週期長度區間為本研究探討之重要課題。 本研究以台北市現況路網進行微觀車流模擬，將路型分類成雙向道與單向道，並挑選忠孝東路幹道作為雙向道之測試路網，仁愛路幹道作為單向道之測試路網。接著以兩組測試路網之現況號誌時制與號誌最佳化軟體Synchro和TRANSYT-7F輸出之最佳化時制進行比較，最後以微觀車流模擬軟體VISSIM進行績效評估，分別探討號誌週期長度之最佳長度範圍。 由號誌最佳化軟體之模擬結果顯示，雙向道的忠孝東路路網獲得改善之機會較低，號誌週期長度維持在150秒為最佳結果；單向道的仁愛路路網中則有調降週期長度之機會，週期長度可由150秒降至120秒。此外，本研究最後比較不同週期長度下與路網績效之關係，結果顯示，於忠孝東路路網中，當週期長度落在120-150秒範圍時，整體路網績效值最佳；於仁愛路路網中，當週期長度落在120秒附近時，整體路網績效值最佳。此結果與號誌最佳化軟體之模擬結果相當。

The traffic volumes have raised constantly since the number of private mode has increased annually in Taiwan. The traffic problems and traffic conflicts, such as congestion in rush hours and traffic jam in urban, are more and more often. In rurban area, the road network is composed of numbers of main arterial, and the arterial is composed of plenty of intersections. To relive the traffic jam is depending on the signal of intersection. As a result, a great signal timing design is the key to make vehicles pass intersection effectively and safely. The study is based on the investigation of the roads in Taipei to explore the problems of signal timing design. The common design of signal cycle length is using longer cycle length within the rush hours in Taipei, which is fairly longer than the optimal cycle length of international rules. Even though it can reach progressing to let vehicles pass more intersections through the processing of the loner cycle length, vehicles on the other way of the crossing roads need to spend more time on waiting and cause the increasing of delay time. The main issue for this study is to reach the balance of number of stops and delay time for vehicles to improve the busy traffic condition for road network. The research method of the study is simulation method, taking the current road condition in Taipei city as setting. Classifying the features of road network into two-way road and one -way road, the study takes East Zhong-Xiao Road for two-way road and Ren-Ai Road for the one-way road as the testing road network. After that, comparing the different output of optimal signal timing plan within two signal timing plans of the testing roads and two signal timing optimization software- TRANSYT-7F and Synchro, the study evaluates the result through VISSIM. The result shows that the possibility of decreasing the signal cycle length of two-way road- East Zhong-Xiao Road is low, remaining the original cycle length of 150 seconds is the best result. For the one-way road- Ren-Ai road, it is more possible to decrease the signal cycle length from 150 to 120 seconds.