Abstract: Traffic flow stability analysis is helpful to reveal the internal mechanism of the improvement of traffic operation efficiency. The car-following models of automated vehicles and manual-driven vehicles were used. Considering the randomness of vehicle space position, the numerical simulation experiment of mixed traffic flow stability under periodic boundary conditions was designed. The characteristics of vehicle speed fluctuation in mixed traffic flow under disturbance were analyzed, and the time of disturbance dissipation under different proportions of automated vehicle was calculated. Meanwhile, the influence of automated vehicles on fuel consumption of the mixed traffic flow was analyzed, based on traffic flow fuel consumption evaluation model. Research results show that the automated vehicles can effectively reduce the dissipation time of disturbance in mixed traffic flow, which is conducive to the improvement of the stability of mixed traffic flow. Moreover, compared with manual-driven vehicles, traffic flow with 100% proportion automated vehicles can reduce fuel consumption by more than 24.57%. The research results reveal that disturbance dissipation time is the intrinsic mechanism that the automated vehicle affects the stability.

Key words: traffic engineering, traffic flow, automated vehicle, numerical simulation, car-following model

摘要： 交通流稳定性分析有利于揭示交通运行效率提升的内在机理。应用自动驾驶汽车与手动驾驶汽车跟驰模型，考虑车辆空间位置的随机性，设计周期性边界条件下的混合交通流稳定性数值仿真实验。分析扰动下的混合交通流车速波动特征，计算不同自动驾驶汽车比例下的扰动消散时间，同时基于交通流油耗评价模型，分析自动驾驶汽车对混合交通流油耗的影响。研究结果表明：自动驾驶汽车能够有效缩减扰动在混合交通流中的消散时间，从而有利于混合交通流稳定性的提升，同时100%比例下的自动驾驶汽车交通流可将手动驾驶汽车交通流油耗降低24.57%以上。研究结果揭示了扰动消散时间是自动驾驶汽车对稳定性影响的内在机理因素。

关键词: 交通工程, 交通流, 自动驾驶汽车, 数值仿真, 跟驰模型