高速公路交織路段車流特性分析之研究

A Study on the Traffic Characteristics in Freeway Weaving Areas

高速公路交織路段中，進出主線與匝道之四股車流於區段內發生交織，導致亂流現象進而使其通行能力下降。由於交織路段之車流特性相當複雜，且實證資料難以蒐集，過去關於交織路段車流的研究仍相當有限。由於近年調查技術的突破，本研究提出以無人機空拍結合電腦視覺影像辨識，進行車流特性分析，並對三處不同型態之交織路段進行資料蒐集。研究結果發現：（1）駕駛人傾向於槽化島鼻端處後產生車道變換，導致交織行為集中於路段的前端；（2）交織路段中的四股車流的平均車速並不相同，過去方法將四股車流合併為非交織車流及交織車流可能會過度簡化；（3）交織路段可能會發生全部車道壅塞或只有部分車道壅塞的情況，在進行服務水準評估時應加以區分。

In freeway weaving areas, the four different types of traffic streams from and to the mainline and ramps interact within the same segment, generating turbulence that reduces operational capacity. Because the traffic flow characteristics of weaving areas are highly complex and empirical data are difficult to collect, previous studies on weaving-section traffic remain limited. Benefiting from recent advances in survey technology, this study employs an unmanned aerial vehicle (UAV)–based aerial photography approach combined with computer-vision image recognition to analyze traffic flow characteristics and collects data from three weaving sections of different configurations. The results of the study revealed the following: (1) Drivers tend to increase lane-changing maneuvers after passing the gore nose of the channelization island, resulting in weaving behavior concentrated in the upstream portion of the section; (2) The average speed of the four traffic flows within the weaving section differs, and past methods that combined the four flows into non-weaving flows (freeway-to-freeway, ramp-to-ramp) and weaving flows (freeway-to-ramp, ramp-to-freeway) may oversimplify the situation; (3) Weaving sections may experience traffic congestions for all lanes or only some of the lanes, and this distinction should be considered when evaluating their level of service.