Phase Transition Investigation Of Cellular Automata Urban Traffic Network Models

The direction of urbanization lies in the extension direction of urban traffic network. In the last two decades, due to the urgent need of urban development and living standards improvement, large numbers of road construction projects have been passed and launched. Currently, urban traffic congestion has made city dwellers get stuck in the nightmare of urbanization through enjoying-the urban life style with ease and convenience. Traffic jam not only causes time and energy wasting, but also restricts city’s economic development via growing air pollution and hazy weather. Hence, finding the effective method to’governance congestion’means no less than fixing the root cause of the problem. Under huge reality background, traffic flow science arises at the historic moment as a burgeoning inter-discipline. Meanwhile, the emergence of various interesting and complex phenomena in the traffic flow study has also caught the scholars’ attention from different fields, which includes physicists certainly.Aiming at the urban traffic congestion problem and using the cellular automata method, we here have established three models, which includes urban traffic network with consideration of traffic signal, vehicle detouring probability and cooperative willingness, to investigate the urban traffic network. The main works are listed as follow:(1) According to the cellular automaton model of Watanabe with parallel updating signal processing, a traffic signal model with random update rule has been proposed to study the urban traffic network. Simulation results showed that, the random update rule has great influence on the traffic system’s critical density of phase transition. Moreover, in order to make the control measures into force and improve the declined critical density which caused by random updating, the possible technique of relaxing the traffic congestion is combining the alternately arranged signals and long-duration time simultaneously when roads are crowed by cars.(2) Based on the urban traffic network model with random update rule that set up by Ding et al, we here proposed a new model with random update rule by considering the probability of vehicle detouring. Numerical simulations of the above-mentioned model indicated that, regardless of whether the detouring direction fixed or not, the increasing detouring probability would surely help the traffic system which governed by random update rule to lift the reduced critical density value. (3) In the light of the BML model with evolutionary game that proposed by Perc, here provided a new BML model by taking cooperative willingness game into consideration. Simulation results suggest that, although the premature of traffic jam is inevitable once the game starts, imitating cooperative willingness can ease the effect of premature seizure on traffic flow due to the introduction of evolutionary games. Furthermore, improving the level of cooperative willingness consensus among agents is a more preferable choice from the beginning.Finally, the conclusion and the outlook of some future works are given at the end of this paper.