考虑前后车速度和减速幅度的元胞自动机模型

三相交通流理论和基本图方法对自由流到拥挤流的相变过程提出不同的解释，双方争议至今没有解决.基于典型慢启动模型规则，本文提出一个考虑前后车速度和减速幅度的交通流元胞自动机模型来探讨自由流到拥挤流的相变.新慢启动模型的减速幅度大小与前车速度相关，两个减速幅度值分别对应缓慢减速和急减速.新慢启动模型的数值模拟结果表明：同一密度值对应的交通状态可能是自由流，也可能是拥挤流；小堵塞集团可以稳定存在于道路系统并有同步的趋势；当道路系统中存在大量不考虑舒适驾驶并倾向于急减速的车辆，在此条件下，三相交通流理论提出的紧致压缩效应不具有合理性，自由流状态可以直接相变为堵塞状态.

Cellular Automaton Model Considering Velocity of the Front and Rear Vehicles and Deceleration Values

Three- phase traffic theory and fundamental diagram approach propose own different interpretations for the phase transition from free flow to congested flow and the controversy between two sides has not been solved yet. Based on typical slow-start model rules, the paper proposes a cellular automaton model of traffic flow considering velocity of the front and rear vehicles and deceleration values to investigate the phase transition from free flow to congested flow. The deceleration value of the new slow-start model is connected with velocity of the front vehicle and the two deceleration values set correspond to slow deceleration and rapid deceleration. The simulation results of the new slow- start model show that the traffic may be in free flow or congested flow corresponding to the same density；small jams can exist steadily in the road system and have the trend of synchronization；under the condition that a lot of vehicles that do not consider the comfortable driving and tend to decelerate rapidly exist on the road, pinch effect proposed by three-phase traffic theory is irrational and free flow can be transited into jams directly.