Structure Analysis and Prevention Measures of Traffic Accidents

本研究提出一种交通事故结构分析方法，用以评估可能采取的交通安全措施。交通事故的特点是交通条件和驾驶员/导航员/飞行员周围的道路/航道/机场布局等多种因素共同作用导致交通事故的发生。这一特点表明，应用故障树分析(FTA)来明确交通事故的结构是有用的。针对交通事故调查报告系统的特点，提出了一种基于事故记录构建交通事故事故树的方法。该方法包括两个阶段，从事故记录中提取部分傅立叶变换，并将提取的部分傅立叶变换叠加形成统一的傅立叶变换。为了找出事故的主要原因和评估安全措施的效果，应进行重要性分析。然而，传统的重要性分析技术不一定适用于这样的交通事故。尽管传统的方法假定因果事件的发生是明确的，但在交通事故中存在着许多难以明确判断其是否发生的人为原因事件，为了解决这一困难，引入模糊集理论的概念，将其组织成一个过程，并通过选取的多个船舶碰撞和机场交通事件的记录进行了具体的演示。然后，将获得的FTS应用于安全评估，以评估建议的安全措施的有效性。通过案例研究，获得了许多有用的信息，包括防止几个因果事件同时发生的重要性。研究结果为制定有效的交通系统安全措施提供了方向。

This study proposes a structure analysis of traffic accidents for evaluation of possible traffic safety measures. Traffic accident is characterized that many factors in traffic condition and road/fairway/airfield configuration surrounding driver/navigator/pilot jointly contribute the occurrence of traffic accident. This characteristics suggests the usefulness of applying Fault Tree Analysis (FTA) to making clear the structure of traffic accidents. There is a rich stock of past traffic accident records because of the surveying and reporting systems.Taking these characteristics into consideration, this study proposed a method to construct a Fault Tree (FT) of traffic accidents from accident records. This method consists of two stages, extracting a partial FT from an accident record and superimposing the extracted partial FTs to form a unified FT.For finding dominant causes of accidents and for evaluating the effect of safety measures, an importance analysis should be conducted. However, the conventional technique of importance analysis cannot necessarily be applied directory on such a FT of traffic accidents. Though the conventional technique assumes that the occurrence of causal event is clearly judged, many human-related causal events, which is difficult to be clearly judged whether it occurred or not, exist in the FT.For resolving this difficulty in evaluation, a new technique has been developed by introducing the concept of fuzzy set theory.These techniques were arranged into a procedure, and was demonstrated in the concrete by using several selected records of ship collision and airfield traffic incident. Then the FTs obtained were applied to a safety evaluation how effective the proposed safety measures are. Through the case study, many useful information was obtained including the importance for preventing simultaneous occurrence of several causal events. The results suggest us a direction in developing effective safety measures of transportation systems.