Improved Model Of Traffic Flow And Simulation Analysis Based On Cellular Automata Theory

Cellular automata model can more truly reflect the actual road traffic situation,and thus in the traffic flow simulation has a great advantage.The model of cellular automaton traffic flow,which is in line with the actual road traffic,is established.The simulation can help to understand some basic rules of traffic flow.It is expected to provide the decision-making tool for the transportation department to formulate policies and solve the traffic problem.This paper focuses on several aspects of traffic flow cellular automata model,including the improvement and simulation of two-lane model,the establishment and simulation of the speed mixed traffic model,the application of model in signal control intersection.The main research work is as follows:Firstly,this paper summarizes the theoretical basis of traffic flow and cellular automata,and introduces and analyzes the existing classical cellular automaton traffic flow model.Based on the update rules of these models and the simulation results of the model,analyze the model and its shortcomings.Secondly,Based on the NaSh model and the STNS model,considering the estimated speed of the vehicle in the process of deterministic deceleration in next step and the dynamic vehicle spacing in the process of vehicle lane change,at the same time taking into account the driver's different driving psychology,a two-lane traffic flow cellular automata model based on safety parameters is proposed.Then the improved model is simulated and simulation by MATLAB under the two traffic rules.One is to prohibit change lanes and overtake and the other is a free change lane.The results shows: The improved model can describe the basic characteristics of the traffic flow,and the maximum traffic volume of the improved model is obviously higher than the STNS model,which is closer to the maximum traffic of the measured traffic and the fitting degree is higher.Thirdly,considering the situation in the actual road traffic,the safety parameter model is applied to the mixed traffic flow.In the model,the express car and the slow car to take a different randomized probability of slowing.And then simulate it by MATLAB.The simulation results show that: The improved model can weaken the role of the slow cars of the system,to a certain extent solve the problem of overtaking of the slow traffic.At the same time,the overall capacity of the road has increased,the road resource utilization rate has been improved,and can make the actual road traffic situation more real presentation.Finally,the safety model is applied to the road system controlled by the traffic lights at the intersection of the main road and the secondary road,and the main road system is simulated by MATLAB.Simulation results show: The model can reproduce the traffic flow characteristics of the road system under the control of the traffic lights.The simulated space system of the main road system shows a zigzag fit the actual traffic characteristics.The time and space diagram of the main road system can simulate the traffic jam at the intersection.The size of the green ratio can have a greater impact on the system traffic.