基于驾驶行为共性的回波速度解释及仿真

Interpreting and emulating echo wave speed based on common characteristics of driving behavior

为了解释车流回波速度现象,提取出驾驶行为共性:驾驶员利用与渴望车速对应的心理车头距判断前方的交通流状况;加速或减速行为是驾驶员根据前方车传递的交通信息和自己对此信息的时间和空间理解来进行的,并且以回波速度向后传递.利用数学方法描述这些驾驶共性,建立了以车头距和驾驶员反应时间等为参数的回波速度模型,解释了车流回波速度现象.使用MATLAB软件对回波速度模型编程,数值仿真加速与减速时回波速度曲线.仿真结果表明:驾驶员反应时间明显影响回波速度,在交通流由自由流转变为拥挤流时的临界车流密度(cρ=25.1vehicle/km)处回波速度最大(cmax=19.8km/h),其大小与相关文献提供的数据吻合.

In order to interpret phenomenon of echo wave speed in traffic stream, the common characteristics of driving behavior is put forward first, namely, drivers judge the front state of traffic stream by the mental headway corresponding to the desired velocity, accelerating or decelerating behavior is selected by front vehicle＇s transfer of traffic information and by driver＇s comprehension of the information from the view of time and space, which is transferred backwards at the echo wave speed. By mathematical descriptions of the common characteristics of driving behaviors a microscopic formula on echo wave speed is provided, which takes headway and drivers＇ reaction time as parameters. The phenomenon of echo wave speed in traffic stream is interpreted. The echo wave speed for accelerating and decelerating were emulated with the MATLAB software. Numerical emulating result indicates that the reaction time of driver affects the echo wave speed obviously. The maximum speed of the echo wave （Cmax = 19. 8 km/h）, which agrees with the value listed in corresponding literatures, occurs at the critical density （pc = 25.1 vehicle/km）, where traffic stream transits from free stream to congested stream.