交通流的一维元胞自动机敏感驾驶模型

在一维交通流元胞自动机NaSch模型的基础上，优先考虑驾驶员的不确定性敏感预期行为， 将随机延迟过程放在确定性减速之前，从而建立一种新的一维元胞自动机交通流模型：敏感驾驶模型 （简称SDNaSch模型），并根据所给出的车辆状态演化的并行更新规则作了数值模 拟，模拟得到的基本图表明，与NaSch模型相比，道路交通量有较大提高，接近于实测数据 ，说明新模型能更贴切地描述交通现象；某些密度区域流量出现两个分支，表明在临界点附 近存在亚稳态；而且会出现畅行相与阻塞相的相分离界面. 从车辆速度分布演化的时空斑图 ，可以看到宽幅运动阻塞相的出现以及畅行相→宽幅运动阻塞相和宽幅运动阻塞相→畅行相 的相变. 接着，计及实际交通情况，考虑行驶车辆中一部分是敏感驾驶，而其余车辆按NaSc h模型规则行驶，数值模拟结果进一步证明，敏感驾驶因素对车流的作用是很大的，随着敏 感驾驶车辆的增多，道路容量也随之提高. 关键词： 交通流 元胞自动机模型 亚稳态 相分离 交通相变

One-dimensional sensitive driving cellular automaton model for traffic flow

Based on the NaSch cellular automaton traffic model, a new one_dimensional cellular automaton model (called SDNaSch model, for short) is proposed through prefer entially considering the sensitive behaviour of drivers, in which the randomizat ion brake is arranged before the deterministic deceleration. According to the ne w update rules of the evolution of vehicles, numerical simulation is conducted a nd leads to some new results. The fundamental diagram obtained by the simulation shows that the traffic capacity of a road is enhanced and closer to the observe d data compared with that of the NaSch model. It is found from the fundamental d iagram that there exist two branches in some density regions, which illustrates the existence of the metastable state near the critical point and the phase sepa ration. According to the evolution pattern of the vehicle speed in space and tim e, the wide moving jams is reproduced with the phase transitions between free fl ow and wide moving jams. With the consideration of the actual traffic situation, i.e., some drivers being sensitive and following the new rules, while others be ing not and following the original NaSch rules, the corresponding simulation ver ifies the remarkable effect of the sensitive driving factor on the characteristi cs of traffic flows. The traffic capacity rises along with the increase in the f raction of sensitive drivers.