The Memory Density Was Studied In Traffic Signal Control System Based On NS-BML Model

Traffic signal management and control directly affect the efficiency of traffic network.Reasonable control of traffic signals in the network can effectively improve the efficiency of network operation.Based on the dynamic characteristics of cellular automata,this paper combines the NS model with the BML model.Taking Manhattan network as the research object,this paper studies the influence of the past vehicle pair and the network operation efficiency,defines the concept of memory density,and determines five strategies,namely,absolute flexibility strategy,long time memory density strategy,short time memory density,bi-directional strategy,intersection vehicle non deceleration strategy.Further improve the flexible network traffic timing and the overall efficiency of the network.The main contents of this paper are as follows:(1)To analyze the dynamic timing problem of traffic lights in the NS-BML model described in the literature,and analyze the principles.(2)According to the proposed problems and combined with the dynamic characteristics of cellular automata,five kinds of management control strategies are formulated,and the operation indexes of the traffic system are clearly evaluated.(3)Based on the Manhattan network,the simulation model is established.The simulation experiment is carried out,the simulation results are compared with the five strategies.The optimal proportion is sought,and the sensitivity analysis is carried out with the static time,density weight factor,cycle and other factors.The results of the study include the following:(1)After the absolute flexibility strategy is adopted,the time allocation is more uniform and the control effect is better.(2)After the memory density strategy,it can not improve the efficiency of the system,which is related to the proportion of historical density.When the ratio factor is 0.5,the average speed of short-term memory density network increases 8.51%and 9.28%compared with the same period.(3)After adopting a bi-directional strategy,it can eliminate the unreasonable phenomenon of waiting in one direction and waiting in the opposite lane.The speed increased by 14.27%compared with the same period.(4)In order to ensure security,the efficiency of the entire network is reduced after the adoption of the intersection deceleration strategy,but this is in line with the reality of the law,and the speed increases-2.64%compared with the same period..(5)The optimal ratio is obtained at 0.35 and 0.65 respectively,and its effect is better than 0.5 and 0.5,and the increase is 1.88%.The effect is worse only with the density of history,and the average velocity is 88.02%,but the effect is still not good at present speed only.(6)The optimal static time is obtained at 15s,and its efficiency is only 5S higher than that of static time,with an increase of 0.65%.The density weighting factor is obtained at 2 locations with an increase of 1.91%.The optimal cycle time is 142 seconds,and the efficiency of the system is increased by 1.89%.