元胞自动机交通流NS模型相图研究

基于开放边界条件下元胞自动机交通流NS模型，模拟入口概率α]、出口概率β]、车辆最大速度Vmax]以及随机慢化概率ρ]对系统流量J]的影响，根据不同流相中流量J]的变化规律，建立NS模型的相图。结果表明，车辆最大速度在一定范围内的增加能提高系统流量，车辆的随机慢化概率在小于临界随机慢化概率ρc]时，不会对系统流量造成影响，而超过ρc]时，随机慢化概率越大，对系统流量的反作用越明显。Vmax]和ρ]决定系统相图。当Vmax=5]，ρ<ρc]时，系统相图只由自由流相和堵塞流相构成，自由流相和堵塞流相被一条曲线分开；ρ>ρc]时，最大流相出现，最大流相区域随着ρ]增大而增加。

Study on phase diagram based on NS model

Based on the NS traffic model with open boundary conditions, the influence of the injected probability α], the removed probability β], the maximum velocity Vmax] and the randomization probabilities ρ] on the flow J] is simulated. Then the phase diagrams are constructed due to the change of J] in different regimes. Results show that J] can be improved along with the increase of Vmax] within a certain range. When ρ] is smaller than the critical randomization probability ρc], it will not affect J]. When ρ exceeds ρc], the bigger the ρ] is, the more obvious reaction on J] is. Vmax] and ρ] determinate the phase diagrams. When ρ<ρc], the phase diagram only consists of the free flow regime and the jamming regime, and the two regimes are separated by a curve. When ρ>ρc], the maximum current occurs and it will increase with the increase of ρ].