八车道高速公路交通事件时空影响范围预测研究

Study on Traffic Incident Spatial and Temporal Influence Range Prediction on Eight-lane Freeways

交通事件降低了道路通行能力,增加了行车安全隐患,提高了行程时间延误水平,对路网运行状态产生了不利影响。当交通需求确定时,不同事件状态下事发路段剩余道路通行能力不同,产生的排队长度、事件持续时间和路段行程时间也具有较大差异。因此,根据事件类型和上游交通需求预测交通事件时空影响范围和路段行程时间,对于采取交通管控措施,降低事件对路网运行状态产生的不利影响具有重要作用。通过波动理论建立八车道高速公路交通事件时空影响范围预测模型;设计仿真试验,使用实测数据对仿真试验进行参数标定;计算仿真结果与模型预测值之差。结果表明:处于二级以上服务水平的单向四车道高速公路,当交通事件造成单车道或两车道封闭时,事件影响范围与交通流率密切相关,事件影响范围较小;当交通事件导致高速公路半幅完全封闭时,受排队车辆车头间距不断减小影响,事发断面上游交通流率呈非线性变化,实测事件影响范围小于模型计算结果;总体来看,当交通事件占据三车道或导致高速公路半幅封闭时,事件对路网运行状态产生的影响较大。

Traffic incidents reduce the road capacity, increase the risk of driving safety,improve the degree of travel time delay,and harm the freeway network. The available power is different under different traffic incidents,and the dissipation scale,duration,and travel time are also different. Therefore, predicting the spatial-temporal impact and road travel time according to the incident type and traffic flow plays an essential role in reducing the adverse effect of the incidents on the road network. Through wave theory,this paper establishes the spatial-temporal incident prediction model on eight-lane freeways. We designed the simulation experiment,used active traffic data to calibrate the simulation parameters, and calculated the difference between simulation and model prediction results. The results show that for a one-way four-lane freeway with a level of service II,when a traffic incident closes one lane or two lanes,the impact of the incident is determined by the traffic flow rate and the impact range of the incident is minor. When the traffic incident leads to half of the freeway closed,the traffic flow rate upstream of the incident changes nonlinearly due to the queuing vehicles headway reduction,and the influence of the incident is less than the calculation result. Generally speaking,when traffic incident occupies three or four lanes of expressway,the incident have a significant impact on the operation state of the road network.