城市公交车与社会车辆混合流速度模型及交通运行状态分析

为了精确解析城市公交车和社会车辆混合运行的状态,在基本路段车速模型适用性分析的基础上,引入公交车流量、社会车辆流量、公交车比例等参数,建立了改进的混合机动车运行速度模型,分别选取单向二车道和单向三车道路段进行交通试验调查,采用Metrocount 5600气压管式车辆分型系统进行数据采集并用于改进模型的参数标定,并分别建立了2种车型的速度差模型,提出了路段混合车流3种不同交通运行状态的评价方法。研究结果表明：同等车流量情况下,不同公交车比例对社会车辆速度的影响表现为3个显著的变化区间;随着路段饱和度的增加,社会车辆和公交车之间的速度差呈现出从几乎不变、快速缩小到接近于零3个较为明显的运行状态;考虑车流组成中公交车比例的变化可以细化路段车流畅通状态、拥堵形成状态以及拥堵状态的判别。

Speed Models of Mixed Traffic Flow on Bus-car and Vehicle and Analysis of Traffic Running State

In order to analyze the mixed traffic running state of bus-car and vehicle accurately,based on applicability analysis of the basic road speed model,authors introduced different traffic parameters,such as bus-car volume,vehicle volume and ratio of bus-car and put forward running speed model of mixed vehicle.By using Metrocount 5600 pneumatic-tube vehicle type system,authors collected the empirical data from three-lanes one-way and two-lanes one-way road section by traffic test investigation and calibrated the parameters of modified speed models.Furthermore,velocity difference models with two vehicle types were set up to describe the mixed traffic flow performance.Evaluation methods of three kinds of traffic running states of mixed traffic flow were put forward.Results show that different ratios of bus-car have the significant impact on the vehicle speed under the same volume of traffic flow in three ranges.With the increment of road saturation,the velocity difference between bus-car and vehicle varies from stable to quick approaching and to zero.Consideration of ratio variation of bus-car in the composition of vehicle traffic flow can refine different discriminations of traffic smooth state,congestion production state and the congestion state judgement.