應用移動瓶頸理論探討慢速車輛對高速公路車流特性之影響

高速公路為台灣公路運輸骨幹系統，作為有效紓解大量車流公路系統之一，如何使運輸效率提到最高，是一大重要課題，然而當車流中出現不當駕駛或車流異質性太高時，往往車流運輸效率沒辦法有效提升，雖然不當駕駛行為在車流中只是少數，但對於車流的影響卻不小，當車流累積每一次受到不當駕駛的影響，車流平均旅行時間將會增加。過去國外對於慢車在車流中形成移動瓶頸(moving bottlenecks)之研究已有一段時間，透過模擬呈現慢車在車流的影響已經非常成熟，但實際車流之慢車微觀行為特性分析，因資料取得不易，此類研究較少，慢車在道路實際影響程度較難得知。本文以移動瓶頸理論為基礎，觀察國道一號東湖交流道之主線車流，探討中間車道之慢車對於車流之特性影響。藉由閉路式電視之車流影像(CCTV)辨識移動瓶頸車輛，量化並分類移動瓶頸行為；同時探討慢車對於鄰近車道之車流特性影響，比較車流出現移動瓶頸時與整體車流表現之差異，最後探討移動瓶頸出現造成原車流之特性差異。

關鍵字

微觀車流行為；移動瓶頸；車流影像辨識

並列摘要

Freeway is the major roadway for providing mobility. To be effective as a corridor, it is important to use lane capacity efficiently. When there are aberrant driving behavior and heterogeneity in traffic flow, the efficiency of road performance tends to drop abruptly. Although aberrant driving behavior is not regularly seen all the time in traffic flow, their influence to the efficiency of traffic flow can’t be ignored: travel time will increase while each time aberrant driving behavior appear. In previous research, several researchers had studied moving bottlenecks of slow vehicles in the traffic flow for a while. Most of the works were based on simulation models according to traffic theories. In contrast to the theoretical development, the empirical studies had fallen far behind due to the difficulties of data collecting. This study aimed to explore the impact by slow vehicles based on the moving bottlenecks theory. The characteristics of slow vehicles were observed, identified and categorized on the survey section of Sun Yat-Sen Freeway. The video images from CCTV were used to build the methodology in measuring and analyzing slow vehicles as well as the moving bottleneck phenomenon. Followed by examining the characteristics of freeway flow for adjacent lanes. The issue of “wasteful” capacity was discussed thereafter.