Double-loop Phase Reduction Model At Intersection And Analysis Of The Influence Of Vehicle U-turn

The signalized intersection is the main node in the urban road network,where the traffic flow at the same time converges.However,with the continuous expansion of the urban area and the continuous increase in the number of motor vehicles,the traffic flow in the existing city has exceeded the design load of the intersection signal scheme,resulting in a decrease in its utilization rate and traffic congestion.Therefore,it is necessary to scientifically and rationally optimize intersection signal control to solve urban traffic problems.Firstly,starting from the signal control technology,this paper introduces the intersection signal control standard,summarizes the phase setting method and signal timing calculation method,and introduces the characteristics of Synchro signal timing software.Based on the traffic organization,all kinds of U-turn methods are analyzed;with the average vehicle delay at the intersection as the goal,the evaluation method of signal control at the intersection is studied,which provides a theoretical basis for the optimization of the intersection.Secondly,taking the signalized intersection of Jianshe Road and Yinxiu Road in Wuxi City as an example,this paper collects data on the geometric conditions,phase design,timing scheme,and traffic demand of the intersection on the spot.Based on this,eight types of intersections are proposed.The signal control optimization scheme is designed,and the signal timing is designed for each scheme with the help of Synchro software.On the basis of the HCM evaluation method,plus the detour delay of the vehicle,the delay evaluation of eight schemes is carried out.Comparing and analyzing the evaluation results of various schemes,it was found that in this intersection,phase reduction scheme D only has one turning traffic flow,which makes management difficult and has good optimization effects for both morning and evening peak periods.Therefore,this article recommends Scheme D as the optimization scheme for this intersection.Finally,this paper analyzes the influencing factors of vehicle U-turn and lane-changing on the delay of mainline vehicles,and uses VISSIM simulation software to construct a road-vehicle average delay as an index,using the single variable principle for the number of U-turn vehicles,U-turn distance,mainline traffic,and lane change times.Four simulation schemes are designed respectively,and the analysis of the simulation results shows that: when the flow of the main line is small,the influence of each factor on the traffic flow is limited;when the flow reaches a certain threshold,the average vehicle delay increases sharply;the influence of the number of lane changes on the average vehicle delay Larger,the delay of 2 lane changes is significantly greater than that of 1 lane change.Then three neural network models of BP,DBN and GRNN were established to fit the simulation data.After comparing the three fitting results,the DBN neural network was selected to be more suitable for dealing with such problems,and its goodness of fit was 0.884 better than that of the other two 0.604 and 0.572 are higher.