交叉路口雙車事故分析

Abstract

道路交通事故的發生通常肇因於一連串不利因素的組合，為深入探討事故發生之影響因素，本研究應用決策樹資料分類機制進行事故發生情境之構建，分析各種事故類型發生特性，以期瞭解事故之全貌。研究範疇設定為交叉路口雙車事故，使用民國92年至民國94年警政署A1、A2道路交通事故資料事故，車種則限定為小型車與機車。 考量事故型態之定義與主題之設定，流程依事故發生地點、幾何與環境、當事者三階段依序探討。由於事故資料呈現高度不平衡，同時缺乏道路實際曝光量資訊，因此藉由觀察決策樹各層節點之間特定事故類型所佔比例之增減，藉以瞭解事故發生特性之傾向。 分析結果顯示，交叉路口雙車事故可彙整為三大類型：(1)受到行車管制號誌時相改變之影響，駕駛人會有較多加減速之操作，進而增加與同向車流發生追撞或擦撞之機會；(2)受限於巷弄視距不良，車輛於路口區域容易忽視橫向車流之威脅，進而在路口附近發生與對向車流發生撞擊，亦或是在路口內發生橫向擦撞；(3)穿越路口事故主要肇因於駕駛人在安全隔離不足的狀態下欲強行穿越路口，其中當事者特性分析顯示，男性駕駛人較具有高風險傾向之駕駛行為。

The occurrence of an accident generally results from a series of unfortunate factors. In order to explore the nature of road traffic accidents, this research applied decision tree to construct the scenarios of accidents.The A1 and A2 types of accident data from year 2003 to 2005, maintained by National Police Agency, were used to analyze small-size vehicles and motorcycles accidents at intersections. Consideration the definition of accident types and issues being studied, the data was sequentially analyzed with respect to locations, geometric and environmental factors, and driver's characteristics. Furthermore, due to the unbalance of accident data and unknown exposure data, this study analyzed the tree structure through comparing the possibility of each accident type between different level and different node of trees. The results indicated that, two-vehicle accidents at intersections could be summarized into three categories as follows. First, due to signal operations, rear-end collision and same-direction side swept accidents were significant and the associated vehicle speed changes at signalized intersections. Second, sight distance is restricted at alley-level intersections. Drivers may ignore the threat of lateral traffic flow and resulted in side-impact, head-on and cross-intersection accidents. Last, left turn crossing accidents mostly resulted from driver’s crossing at the intersections under insufficient gaps. Meanwhile, according to the driver's characteristics analysis, male drivers tended to have risky driving behaviour.