市區道路安全路線選擇之研究

Abstract

過去在進行交通量指派時，多是以路線距離長度或是旅行時間做為路線選擇準則，這是由於時間是駕駛者在進行交通行為時最關切的，但道路安全是除了時間之外最與我們切身相關的，透過問卷瞭解，61%的受訪者在進行路線選擇時會考慮安全因素，由此可見安全實為一重要路線選擇影響因素。「安全」才是回家唯一的道路，藉由安全路線的提供，可以導引車輛行走於安全性較高的道路，對於整體路網交通安全的改善帶來幫助。 本研究目的為建立一安全路線選擇方法，考慮過去多種道路安全評估方法後，以風險的概念來建立本研究之道路安全評估方法，「道路風險」即是駕駛者行駛在道路時，遭遇交通事故的可能性以及交通事故對其可能造成的損害。為了避免有低估路線風險的情形發生，本研究在進行路線選擇時將同時考慮路口及路段風險，由於過去在進行最短路徑尋找時，只單考慮路段之屬性，故本研究在建立安全路線選擇方法時，將路口及路段風險做結合成單一值，即可利用現有之規劃軟體最短路徑功能尋找最安全路線。 本研究以台北市大安區及中正區之路網做為案例分析，尋求多個起訖點間之最短路線及最安全路線後做比較，發現在顯著水準0.05下，本研究之最安全路線確實較最短路線來的安全。此外也透過問卷給予受訪者最短路線及最安全路線之距離及事故資料，瞭解其在同時獲得兩種資訊時，其路線選擇行為之改變，結果顯示從最短路線轉移至最安全路線之轉移比例很低，此種結果應是未將熟悉度排除之原因，故若要確切瞭解駕駛者在距離及安全之間的權衡，務必要將熟悉度排除才行。 藉由安全路線的提供，將可導引駕駛者行駛於安全路線，減少其事故風險，進一步還可將安全因素納入交通量指派中，同時考慮效率及安全，以模擬出更接近現實之交通行為。

Conventionally, traffic assignment is conducted based on the travel distance or travel time. Besides travel distance and travel time, road safety is also an important factor which affects road users when they drive in the road. According to the questionnaire survey results, about 61% road users who were given a visit will take the safety into the consideration of route choice. Through safety route information, it can guide road users in safety roads, and raise the safety effects of the network. For the reason, safety road choice is a worthy study. This paper presents a new idea to find the shortest path based on the minimum road accident risk. “Road accident risk” means that the probability and the severity of the accidents which road users might encounter when they drive in roads. An accident risk estimation model was developed and applied to assess the accident risk of urban road network. In the past, the shortest path only considers the section of road. To clarify the situation of underestimating the accident risk, this paper considers the risk both of intersection and the section of road. Then, using shortest path searching method the minimal risk path would be found. A comparative analysis to compare the shortest distance path and minimum accident risk path has resulted in the significant difference of the path choice, using the data of Taipei City. Furthermore, the results of the other questionnaire survey about transferred behaviour shows that few people will transfer to the minimum accident risk path when they get the information both of the shortest path and the minimum accident risk path. Therefore, to search for the minimum accident risk route will be meaningful for involving in the traffic assignment or in the route navigation system in the future.