冰雪路面城市快速路跟驰模型研究

Study on Car Following Model of Snow and Ice Urban Expressway

针对冰雪路面城市快速路的跟驰模型进行了研究。首先对两种常见的冰雪路面进行了交通调查。根据调查结果对不同冰雪路面城市快速路交通流的自由流速度、平均速度、速度分布,相邻跟驰车辆的车头时距、车头时距与相对速度的相互关系等微观特性进行统计分析,定量地研究不同冰雪路面形态对城市快速路跟驰行为的影响。其次,对不同类型的优化速度函数特征进行对比分析,依据Greenshields速度-密度关系建立期望车速模型,依据车辆不同跟驰状态建立冰雪路面最小安全距离模型,并由此构建冰雪路面优化速度模型。基于现有跟驰理论研究成果,以线性跟驰模型建模思想对全速度差模型进行改造,结合冰雪路面优化速度模型构建适用于冰雪路面的新跟驰模型。最后,利用实测数据对模型参数进行标定,并通过设计实验分析模型的稳定性、加速度非对称性。同时,利用调查数据对新模型和全速度差模型进行模拟分析,结果证明该模型更贴近冰雪路面城市快速路实际交通流,可以为冰雪路面下交通管理措施的制定提供理论支持。

Car following model of urban freeway under snow condition is studied.First,urban road is classified according to it＇ s surface in winter,and then organizes traffic survey of the two common snow and ice road combined with the actual situation of urben expressway.According to the result of the survey,a statistical analysis of traffic flow characteristics was made such as free flow velourban,average velourban,the characteristics of velourban distribution,headway between adjacent vehicles,the relavance between relative speed and headway,the driver＇ reflect characteristics,then the influence on following behavior of different snow and ice urban expressway was studied quantitatively.Second,the characteristics of different types of optimization voleurban function were analyzed comparatiaely,and expected speed model according to Greenshields speed-density relationship was built,and minimum distances model according to car-following state was built,and thus snow and ice road speed optimization model was built.Based on the existing research of car-following theory,using the modeling thoughts of linear car-following model,combining with full velourban difference model,the new car-following model was established which is suitable for snow and ice urban express way.Finally,the measured data is used to calibrate the model,and then the model of stability,acceleration asymmetry were analyzed through the designed experiment.At the same time,survey data were used to simulate and comparatively analyzed the new model and the full velourban difference model.The results show that the simulation of the new model is more close to the actual traffic flow.It can provide theoretical support for formulating icy and snowy traffic management measures.