城際大眾運輸安全風險評估之研究

Abstract

政府期有效疏解交通擁塞、減少環境污染、節約能源，不僅鼓勵民眾搭乘大眾運具，亦提供民間業者投資興建大眾運輸系統與設施之獎勵辦法，以增加大眾運輸供給量。政府一方面鼓勵搭乘大眾運輸，但又缺乏建立一套評估運輸安全之審查機制，以充分保障旅運者「行」的安全。此外，以往城際運輸之相關研究大多以旅行時間、旅行成本等屬性為預測模式之主要考慮變數，然運輸安全的風險值卻鮮少融入旅運者選擇行為以及運量預測程序之中，忽略運具安全風險對旅運者實際選擇行為之影響。 「風險」被定義為「因為個人行為或事件導致影響人類價值的可能性」。「風險」係指一事件具有「不確定性」的發生機率，並可能造成損益利弊產出之「後果」。隨著旅次活動日益頻繁，運輸系統的運量與效能均大幅提高，然而隨著交通技術複雜性與交通狀況不確定性之增加，人類為求謀生所產生之旅次亦須面對可能發生交通意外事故的風險。因此，交通運輸雖提供人與貨物在空間上移動的服務功能，亦增加了人類死亡的風險。 本研究在考量運輸風險影響個體生命安全甚鉅之情況下，嘗試以產業風險指標中ALARP(As Low As Reasonably Practical)準則為分析基礎，應用FN-curves分析技術與相對風險概念作為評估運輸系統安全風險之指標，並結合個人風險、社會風險等概念建立一套我國城際大眾運輸安全風險評估之程序。在評估程序中因考量旅運者對於風險的概念相當模糊且風險具有「不確定性」之發生特質，乃透過同為描述不確定性之模糊三角函數作為量測風險感認之工具，輔以各類運輸工具近十年來運具乘員（mode occupants）之實際風險資料，設計運具損失頻率、後果嚴重程度量測命題之風險感認問卷。進而結合主觀、客觀風險值以建立綜合風險評估架構，尋求旅運者所能接受之風險水準，建立國內城際運輸之安全標準，以供研擬改善行車（飛航）安全之依據。 在風險感認量測方面，國內航空與國道大客車乘客均以台鐵為第一優先轉搭之運輸工具，此一選擇行為與旅運者咸認台鐵為較安全運具有關。該結果亦顯 示行車風險高低確實會影響旅運者的運具選擇行為。在社會感認風險水準評估方面，國內航線、台鐵以及國道大客車事故規模分佈皆落在無法容忍風險水準線以外區域，顯示各運輸系統在目前國內城際運輸市場中皆屬於高風險性之運輸活動，依據社會風險行為邏輯，營運者應不惜經濟成本降低風險，待風險降至門檻值以下方能考慮符合經濟條件之改善措施。就旅運者而言，則須立即採取風險規避行為以降低風險。

The government has been devoted to encourage people to use public transportation for the purpose of solving traffic congestion, reducing air pollution as well as saving energy. However, on the other side, the transportation safety of public transportation is not definitely guaranteed by the government to attract people to use. Risk perception for traveling is commonly recognized as a significant factor for mode choice decision, however, only few empirical studies have included this important factor into their works. "Risk" is defined as the possibility that human actions or events lead to consequences that have an impact on what the human value. Transportation provides service function for human being and goods moving in space, but also brings the risk of death to mankind. This study is undertaken to develop a framework for measuring the travelers' risk perception for intercity transportation based on the ALARP criteria and FN-curve technology of industry risk management. A face-to-face interview was conducted to collect required data and the Fuzzy Sets Theory was employed to measure travelers' risk perception for different modes of intercity transportation. Besides, we measure risk by asking their risk perceptions, including the probability of accident, and the severity of accident, so as to establish the threshold of tolerable risk for intercity travel. The study results show the transportation risks of domestic air lines, railway and highway intercity bus service are all higher than the tolerable risk. The operators of intercity transportation industry should seek the feasible techniques to improve the safety quality without regard to the cost of implementation. The results of this study not only explore travelers' acceptable risk for intercity transportation, but also provide valuable information for domestic transportation safety management.