两车道交通流的波动分析

Wave properties of a traffic flow model for freeways with two lanes

对一个由快慢两条车道组成的交通流系统,将基于速度梯度的动力方程应用到每条车道上,得到一种新的交通流动力学模型,可以用来揭示车流的小扰失稳和走走停停等非平衡特性.研究了该模型的波动特性,包括冲击波、稀疏波和一阶波传播,数值计算结果表明该模型能够较好地处理冲击波和稀疏波现象,也能够正确地再现走走停停的交通现象.此研究有助于进一步理解多车道的驾车行为和多车道交通流的非线性动力学特性,从而可以提高交通管理与控制水平.

A new continuum traffic flow dynamics model for freeways with two lanes where the faster vehicles are allowed to travel on both lanes while the slower vehicles are allowed to travel on the slower lane only, is developed through applying the speed gradient-based momentum equation for each lane. Some non-equilibrium phenomena of traffic flow such as small disturbance instability and stop-and-go waves can be reproduced by the new continuum model. The wave properties of the new model, which include shock waves, rarefaction waves and first order wave of the two lanes, are respectively studied. The numerical results show that the model respectively reflects the shock waves and rarefaction waves of the two lanes, and the figures about first order wave speeds of the two lanes respectively describe the stop-and-go traffic on both lanes. This study can further help understand the complicated driving behavior and the nonlinear properties of traffic flow dynamics on multilane freeways, and then improve the traffic control and management.