Research On Traffic Flow Model Based On Cellular Automaton And Fuzzy Control

With the development of national economy, the people's demand of transportation becomes increasingly expanding, traffic problems have became one of the most important issues that concerned by countries all over the world. The aim of traffic flow research is to build traffic flow model which can describe the general properties of the real traffic and to disclose the basic laws of traffic flow. In this way, traffic congestions can be prevented and alleviated, and basic traffic support can be provided to the harmonious development of the society. Thus, researching on traffic flow theory is not only profound scientifically significant, but also valuable for engineering application.As a kind of emerging traffic flow microscopic models, cellular automaton models based on cellular automaton not only can retain the non-linear characteristics of complex traffic systems, but also are suitable for rapid computer simulations and have flexible rules. Consequently, cellular automaton models have been widely adopted by the traffic scientists.Based on cellular automaton, this paper has a research on the model building, simulation and direction of the traffic flow model of cellular automaton. The main results achieved in this paper can be summed up as follows.Firstly, an improved CA model was proposed to describe the traffic flow with a single lane road under the periodic boundary conditions on the basis of NS model. Considering the different speed with the different safety distance, reaction time and deceleration distance, this model claims that the motion of a vehicle at one time step depends on both its headway and the speed of the vehicle, thus including indirectly the influence of its neighboring vehicle. In addition, the different safety distance was introduced to descript the deceleration behavior of vehicles with different speeds.Since the different safety distance was introduced into this model and differences of speeds were taken into account, this model gives a better description of the phenomena observed in the traffic flow and gives a reasonable depiction of the motion of a single vehicle.On the other hand, a new cellular automaton model based on fuzzy control is presented in order that the traffic flow based on cellular automaton can be more consistent with true traffic phenomena. Considering that the reactions of drivers to their velocity and distance are fuzzy, fuzzy illation mechanism can be introduced into the randomization process of a single vehicle. In the fuzzy control rules, the distance of the vehicle, the velocity of the vehicle and the time of the diver's reaction are the input. After a succession of fuzzy illation, the randomization deceleration probability of the vehicle at this time can be obtained.Through computer simulations, compared with the other NS model, we can find that the randomization deceleration probability of the vehicle is not changeless any more, is decided by the distance of the vehicle, the velocity of the vehicle and the time of the diver's reaction. For this reason, the new model based on fuzzy control can reflect the influence of the true traffic environment on the driver.