機車是台灣日常使用最為普遍的運具，雖然駕駛機車具危險性，由於機車的便利性，機車仍是很重要的交通工具。許多高齡者在日常活動中使用機車為運具，尤其是大眾運輸服務不足的地區。有許多嚴重的交通事故是發生在路段上，但很少研究探討路段事故發生原因，本研究利用內政部警政署民國95年至民國99年道路交通事故資料庫，分析高齡機車駕駛者路段事故，以了解高齡機車駕駛者路段事故的主要事故特性。高齡機車駕駛者路段交通事故共計22,861人次(32.3%)，其中以雙車事故17,813人次(78%)比例最高。本研究進一步分析雙車事故之碰撞分析，分析結果發現路段上之主要三種事故類型為同向擦撞、側撞與追撞，另外並利用雙方當事者的車輛行動狀態（直行、橫越道路、迴轉）和車損位置，推估事故發生情況。此外，路段主要分隔型態共15類，本研究應用分類樹分析方法合併碰撞類型同質之分隔型態，分析結果顯示，高齡機車與小型車事故分隔型態歸為四類，機車與其他機車事故的分隔型態歸為三類。依據事故分析結果，本研究彙整高齡駕駛者在路段應特別注意的交通安全觀念，希望能提高他們的機車安全駕駛觀念，幫助他們避免交通事故的發生。 In Taiwan, motorcycles are a popular mode of transportation. Although motorcycles are a dangerous transportation mode, they still play an important role because they are a convenient means of transportation. Numerous seniors ride motorcycles for their daily activities, especially in rural areas where public transportation is infrequent or nonexistent. There have been numerous serious accidents involving senior motorcyclists occurring in straight lanes, but there are few studies investigating the causalities for this type of accident. This study aims to identify the accident characteristics for senior motorcyclists by analyzing crash data involving elderly motorcyclists from 2006 through 2010. In total, 22,861 (32.3 %) senior motorcyclists were involved in accidents occurring in straight lanes, and 17,813 (78%) of these were two-vehicle accidents. We investigate two-vehicle accidents to understand their accident characteristics, and our results show that the three major accident types in straight lanes are the following: the sideswipe accident not resulting from an improper turn, the sideswipe accident resulting from an improper turn and the rear-end accident. This study use the results of Classification tree to find out four major road configurations types of the accidents between older motorcyclists and small vehicles ,and also three major road configurations types of the accidents between motorcycles. Based on the analysis results, we provide a summary of safety concepts for senior motorcyclists to increase their safety awareness and help them avoid traffic accidents.