车辆质点系交通流参数描述及仿真分析

Description and simulation analysis of traffic flow parameters of the vehicle particle system

基于车辆质点系表征交通流状态,并以瞬时特定路段区域内车辆质点系质心参数为基础表达交通流参数。设定3种交通流量变化趋势和2种路段车辆类型构成,应用仿真分析方法,对比分析车辆质点系质心参数表达的交通流参数与传统参数在时空状态上的异同。结果表明:基于质心参数所表征的交通流速度υ_(c)与区间平均速度υ_(s)趋势相同,且质心速度υ_(c)更能实时反映交通流速度的时空同步变化特征,同时能反映车辆质量特征(即惯性特征)及分布特征对交通流态势的影响,而区间平均速度υ_(s)有时间滞后性;对比2种方法表征的交通流密度参数,其空间分布状态基本一致;传统的交通流流量参数的时变过程,相对于质心参数所表征的交通流流量具有时间滞后性。

In this paper,the state of traffic flow is represented by the vehicle particle system,and the traffic flow parameters are expressed based on the centroid parameters of the vehicle particle system in a specific instantaneous section area.The spatio-temporal similarities and differences between the traffic flow parameters expressed based on the centroid parameters of the vehicle particle system and the traditional parameters are analyzed by setting three traffic flow trends and the composition of two types of vehicles on the road segment.The results indicate that the trend of the traffic flow speed υ_(c) is the same with the space mean speed υ_(s),the former being represented by the centroid parameters.Moreover,the centroid speed υ_(c) can better timely reflect the spatio-temporal synchronous change characteristics of the traffic flow speed and also reflect the impact of vehicle mass(i.e.inertia)and its distribution characteristics on the changing situation of the traffic flow.However,the space-mean speed υ_(s) has a time lag compared to the centroid speed υ_(c).By comparing the traffic flow density parameters characterized by the two methods,the spatial distribution state is found to be basically consistent.The traditional time-varying process of the traffic flow parameters has a time lag compared with the traffic flow represented by the centroid parameters.