基于云理论的人车冲突严重度研究

Study on pedestrian-vehicle conflict severity grade based on cloud theory

为科学判断过街行人与机动车冲突的严重度,提高过街行人安全性、减少交通事故风险,选取对过街行人与机动车冲突影响比较显著的碰撞时间(TTC)和冲突速度(CS)两个因子为评价指标,提出一种新的基于云理论的行人与机动车冲突严重度判别模型。首先,引入过街行人-机动车冲突的相关概念,分析碰撞时间和冲突速度对人车冲突安全性的影响,分析人车冲突严重度判别过程中评价指标自身的随机模糊性问题,建立评价指标属性离散标准,并由此构建人车冲突严重度矩阵,确定了人车冲突等级。然后,介绍了云模型相关理论,利用已建立的人车冲突严重度矩阵构建其云推理评估模型,实现了人车冲突严重度的定性概念与评价指标定量概念之间的自然转化;该模型充分利用云关联规则建立了云推理器,由此计算得到的冲突严重度和严重等级为最终评价结果,并根据冲突严重度对人车冲突进行了排序。最后,随机选取某条道路的过街人车冲突的样本数据,按提出模型计算得到了人车冲突严重等级,并与常用的评价方法相比,以验证该评价方法的合理性。研究结果表明,基于云理论的人车冲突严重度评价简单,判断准确性和可靠性较高,具有一定的应用价值。

In order to scientifically judge the severity of the traffic conflict between crossing pedestrian and vehicle,improve the safety of pedestrian crossing and reduce the risk of traffic accidents,the two factors,including time to collision(TTC)and conflicting speed(CS),which have significant influence on pedestrian-vehicle conflict severity,were selected as evaluation indicators,and a new model of pedestrian-vehicle conflict severity based on cloud theory was proposed.Firstly,the concept of crossing pedestrian-vehicle conflict was introduced to analyze the impact of time to collision and conflicting speed on the safety of pedestrian-vehicle conflict.At the same time,the randomness and fuzziness of the evaluation indicator itself in the judging process of the severity of the pedestrian-vehicle conflicts were analyzed,and the discretization criteria for evaluation indicators were established.Thus,the severity matrix of pedestrian-vehicle conflicts was established to determine the severity grade.Secondly,the cloud model theory was introduced to establish the cloud reasoning assessment model of the vehicle-pedestrian conflict severity using the constructed severity matrix,which implements the natural transformation between the qualitative concept of the severity of the pedestrian-vehicle conflicts and the quantitative concept of the evaluation indicators.The model makes full use of cloud association rules to build a cloud inference engine.Thus,the conflict severity and the severity grade were calculated as the final evaluation results.Simultaneously,according to the conflict severity,the conflicts between pedestrian and vehicle were sorted.Finally,the samples of pedestrian-vehicle conflicts on a certain road were randomly selected,the severity grade of pedestrian-vehicle conflicts obtained from the proposed model was compared with the commonly used evaluation methods to verify the rationality of the new model.The results show that the severity assessment of pedestrian-vehicle conflicts based on cloud theory is simple,accurate and reliable,and has a certain application value.6 tabs,8 figs,38 refs.