摘要
Nagel和Schreckenberg于1992年提出了著名的Nagel-Schrechenberg（NaSch）元胞自动机模型，该模型虽然形式十分简单，但却可以描述一些实际交通现象。同时也存在很多不足之处，如NaSch模型的最大流量和临界密度远低于实际交通中的数值，它也不能重现交通流的一些重要特性。本文提出了一种考虑当前车辆前方两个车辆影响的具有交通信号控制的单车道元胞自动机模型，根据双倍视距模型的思想修改了NaSch模型的加速规则，计算机模拟结果表明，考虑了次近邻影响的模型能够呈现真实交通中观察到的一些复杂交通流现象，且最大流量和临界密度比未考虑次近邻影响的模型都有了显著提高；此外，模拟结果也表明了交通信号周期对最大流量和临界密度的影响，最大流量随交通信号周期的增大而减小，临界密度随交通信号周期的增大而增大；最后，文中还讨论了近邻车辆的敏感系数和次近邻车辆的敏感系数的影响。模拟结果表明，固定任何一个参数的值，最大流量都会随另一个参数的增大而增加，但是对流量的影响显著，说明近邻车辆的影响大于次近邻车辆的影响。
Nagel-Schreckenberg （NaSch） cellular automata model was given by Nagel and Schreckenberg in 1992. Though NaSch model is simple, it can describe some traffic phenomena in reality. However, the transit capacity of NaSch model and critical point are much lower than those of real traffic lane cellular automata model of traffic and it cannot reproduce some important characters of traffic flow. In this paper, a new singleflow controlled by traffic signal is given, in which the influence of the nearest neighbor vehicle and the next-nearest neighbor vehicle is considered. A type of the driving strategies used in the double look-ahead model has been employed to replace the acceleration rule of NaSch traffic model. The simulation results show that the improved single-lane traffic flow model, in which the influence of the next-nearest neighbor vehicle is considered, can reproduce some traffic phenomena that have been observed in the real traffic, and the maximum flux and the critical density are improved greatly. Moreover, the cycle time of traffic signal has much influence of maximum flux and critical density. Maximum flux decreases with increased, while critical density increases with increased. Finally, the influence of the sensitive coefficients is discussed. Suppose, and are the sensitivity coefficients of the nearest neighbor vehicle and the next-nearest neighbor vehicle respectively. The simulation results show if either of the parameters and is fixed, maximum flux increases while the other parameter increases. But the flux increases more evidently with increased than that of with increased, which shows the influence of the nearest neighbor vehicle is great than that of the nextnearest neighbor vehicle.
