因應事故發生自動控制車隊變換車道邏輯之構建—以單一自動車道為例

Abstract

世界各國為了解決交通擁擠及其伴隨而至之交通事故、能源消耗、環境污染與運輸安全等問題，皆致力於發展智慧型運輸系統。而在智慧型運輸系統的七個子系統中又以自動公路系統為最高科技的一個子系統，也是發展智慧型運輸系統的最終的目標。以高速且小車間距前進的自動控制車隊，若遇到路段下游有事故的產生，將對系統產生重大的衝擊。雖然現在的科技還在測試的階段，不過快速的反應事故所帶來的車道阻塞也是先進自動公路系統的關鍵性議題，但目前仍鮮少有自動公路系統發生事故時的相關研究。 本研究是探討在單一自動控制車道之自動公路系統對事故發生時作因應事故之反應，目的在於建立一個變換車道邏輯，使得自動控制車輛能尋找變換車道機會順利變換到鄰近車道，而這些嵌入的交通控制邏輯都是基於基本的安全需求。首先建立事故上游之三個動態區域來規範自動控制車輛在事故上游的車隊拆解、事故引起之跟車及變換車道、以及強制煞車，然而本研究著重在變換車道部分，以車輛相對速率觀點及車間距切入，藉由防止車輛縱向及橫向碰撞來做判斷變換車道之邏輯，並且以程式語言撰寫控制邏輯，做情境敏感度分析，找出成功地變換車道與鄰近車道之車流狀況、擁擠程度、車速等之關係。 我們以變換車道所需時間來評估變換車道邏輯的績效。最後結果顯示在AC車輛為5輛、在鄰近車道車流量為600vplph、以時速70kph的情境，將所花的平均變換車道時間繪製出關係圖，發現該情境呈現為圖形的一個鞍點。

Many countries around the world devote to develop Intelligent Transportation Systems (ITS) to solve congestion problems, which coupled with some issues of incidents, consumption of energy resource, environmental pollution, and transportation safety. Automated Highway System (AHS) is not only the most hi-technical subsystem in the 7 subsystems of ITS, but also the ultimate goal of development of ITS. An automated-control platoon approaching with high speed and small vehicular spacing will face to critical impacts when incident occurs on downstream highway. Prompt response to lane-blocking incidents is a critical issue in development of advanced AHS although all the limited existing AHS technologies are on trial. But there are few researches to discuss these issues. This paper focuses on the response to incidents for single-automated-lane highway system to design a lane-changing logic which permits automated vehicles (AC) change to adjacent lane. The embedded traffic control logic is based on the safety requirement. First we present three dynamic spatial zones, which are platoon decomposing, incident-induced car-following and lane-changing, and mandatory braking. However this paper is focus on incident-induced lane-changing, and embeds control logic with the views of relative velocity and vehicular spacing to make lane- changing decision via avoiding longitudinal and lateral collisions. Then, we compose C programming language to do sensitivity analyses of many scenarios, and find the relationships between successful lane-changing and traffic flow, variable traffic condition, and vehicle speed. Finally, we calcute the average lane-changing time of AC vehicles to evaluate the lane-changing control logic.And the result shows that 5-vehicle platoon which approaches in 70kph, and the flow of the adjacent lane is 600vplph, is a saddle of all traffic conditions.