A Method Of Anti-overflow Control For Trunk Line Based On Phase Difference Optimization

As the main road skeleton of the city,urban trunk lines bear huge traffic pressure.At the same time,due to the sharp increase in the number of urban motor vehicles in recent years,the congestion of urban trunk lines is becoming more and more serious.Especially in recent years,the phenomenon of traffic overflow has occurred in major cities.The essence of traffic overflow is ultimately the imbalance of supply and demand.When the queues generated at downstream intersections occupy all of the downstream to upstream intersections Road space.If the traffic overflow phenomenon is not controlled as soon as possible,the traffic overflow will quickly spread in the road network,from the congestion of an intersection to the closure of all the nearby intersections,and even paralyze the entire transportation network.Therefore,it is of great practical significance to study the mechanism and prevention strategy of traffic overflow.This analysis analyzes the different queuing situation of the fleet reaching the downstream intersection,discusses the queuing of the platoon of the first vehicle and the queuing of the rear vehicle of the fleet,and uses the improved traffic wave model to establish the maximum number of straight vehicles when the platoon of the first vehicle and the rear vehicle are blocked.Calculating model of vehicle queuing length and model of calculating the maximum queuing length of left-turn vehicles.According to the concept of traffic overflow,if the queuing length of the road section exceeds the length of the road section,overflow will occur.Based on this idea,the paper establishes a queuing length restriction model.Therefore,the maximum vehicle queuing length for straight and left-turning road sections is limited to the range of road sections,and the resulting phase difference range is a reasonable phase difference range that can avoid traffic overflow.In this paper,considering the special supersaturated form of traffic overflow,a parallelogram delay model of saturated coordinated road sections is established,and the different obstruction conditions of the convoy arriving at the downstream intersection are also considered,and an optimal model of minimum delay phase difference suitable for trunk line coordinated control is established.Based on this,the reasonable phase difference range derived from the left-turn queuing length and straight-line queuing length limit models is used as the limiting condition of the optimization method,and the phase difference value that can prevent the occurrence of traffic overflow and minimize the delay is solved.Finally,taking the actual road traffic conditions as an example and combining the VISSIM simulation system to verify the validity of the model,the road network is constructed according to the surveyed intersection data,and the data such as the vehicle type distribution,traffic flow,signal timing,and phase difference of each intersection are entered into the basis.Simulation model.The optimal phase difference value is calculated based on the phase difference optimization trunk line anti-overflow control method,and the microscopic simulation software VISSIM is used for simulation verification,and the status of the current plan and the optimized plan are compared and analyzed in terms of queue length and delay time.Through case studies and analysis,it is confirmed that the main line anti-overflow control method based on phase difference optimization proposed in this paper can prevent the occurrence of traffic overflow,and at the same time reduce the delay time of vehicles passing through intersections.