Construction And Simulation Of Traffic Flow Model Based On Continuous Cellular Automata

In recent years,with the rapid development of the national economy,the demand for traffic by urban residents has increased significantly,and the number of motor vehicles in our country has also increased rapidly,although the scale of the road network system is also expanding rapidly.However,it is still unable to meet the growing number of motor vehicles,which has brought great pressure to urban traffic operation,especially in large cities,traffic congestion is particularly serious.The research of traffic flow theory has become a hot topic to solve the traffic problems and link traffic congestion.the construction and research of road traffic flow simulation model plays a very important role in combing the traffic situation and alleviating traffic congestion.Traditional cellular automata(CA)is a kind of traffic model with spatio-temporal discrete characteristics,and the calculation is simple and convenient,so it has become an important tool to study the operation mechanism of road micro-traffic flow.In this paper,the driving characteristics of heterogeneous drivers are taken as the breakthrough point for the study of traffic flow characteristics,and the traditional cellular automata model is improved to construct a continuous cellular automata model based on the driving characteristics of heterogeneous drivers.Different car-following rules are used as the driving characteristics of different drivers,which makes the simulation more in line with the actual traffic phenomenon.The main work and results of this paper are as follows:(1)Firstly,the research status of traffic flow theory at home and abroad is combed,and the great contribution of discrete cellular automaton model to the current micro-traffic flow research is expounded.At the same time,this paper briefly expounds some disadvantages of discrete cellular automata model in the simulation process,leads to the continuous cellular automata model studied in this paper,and compares it theoretically with discrete cellular automata model.(2)A single-lane continuous cellular automaton traffic model is constructed,and different car-following rules are used to represent the driving characteristics of different types of drivers,and genetic algorithm is used to calibrate the parameters of car-following rules.Based on these models,the influence of heterogeneous driver mixing ratio on traffic flow and traffic congestion is analyzed and explained.(3)Considering the actual situation of road operation,two one-dimensional cellular spaces are connected through STCA lane switching rules with variable safe distance,and a two-lane continuous cellular automaton model based on driver heterogeneity is constructed.The influence of mixed proportion of heterogeneous drivers on traffic flow,lane changing frequency and traffic congestion in two-lane section is analyzed by simulation,and the lane changing probability of vehicles in the model is adjusted.The influence of different lane change probability and driver heterogeneity on road traffic flow is analyzed.(4)The actual intersection is studied and analyzed,the continuous cellular automaton model of signalized intersection is constructed,and the operation mechanism of the entrance vehicle is analyzed.in the model,the open boundary condition is used to deal with the boundary vehicle of the system.The entrance road section is divided into free lane change area,forced lane change area and guide lane area.when the vehicle is in different areas,different lane change rules will be adopted.The road operation under different conditions(driver mixing ratio,green letter ratio)is simulated,and the influence of driver heterogeneity and different green letter ratio on traffic flow at intersections is studied and analyzed.Based on the study of microscopic traffic flow theory,this paper expounds the significance of cellular automaton model to the study of traffic flow theory,and improves the cellular automaton model,combined with the characteristics of spatial continuity in the process of actual vehicle operation.A cellular automaton model with spatial continuity is constructed.Compared with the traditional cellular automaton model,the road section is no longer divided into cells according to the fixed length,but the vehicle in the road section is regarded as a cell to store the specific information of the vehicle.The heterogeneity of the driver is described by different car-following rules,and a continuous cellular automaton model based on the heterogeneity of the driver is constructed,and the single-lane,two-lane and signalized intersection are simulated and modeled.The influence of driver heterogeneity on traffic flow is studied,so as to construct a traffic flow model which is more in line with the actual road operation status.