Research On The Iterative Adjustment Of Signal Timing Based On Sampling Trajectory Data

The number of vehicles and traffic demand has been increasing in recent years,leading to the heavy congestion on the urban road.The arterials in the city take the major traffic flow and the intersections are the key nodes of the urban traffic control,so the signal control of them has a great impact on the efficiency of the urban road network.In fact,the signal timing plans need to be adjusted according to the actual traffic state from time to time.However,the maintenance cycle of signal timing adjustment is usually too long.On the other hand,the sampling trajectory data provided by the mobile navigation application has been developing rapidly nowadays,which can evaluate the road traffic state,thus instructing the signal timing optimization.Besides,the trajectory data has another advantage over the traditional detector data,which can help identify the main arterials with large traffic flow in the road network and then set coordinated control for them.Based on this idea,this paper studies the signal timing optimization based on sampling trajectory data,aiming to propose a simple and effective signal timing optimization method which can improve the traffic state of the whole network through iterative optimization.The main achievements and contributions of this paper include the following aspects:1.The cumulative sufficiency of sampling trajectory data is proved from the aspects of both theory and simulation experiment.Through theoretical deduction and simulation experiment,it is proved that the sampling trajectory data can sufficiently reflect the overall road traffic state after accumulating enough data,so it can be used to instruct the optimization of signal timing.2.We make full use of the advantages of trajectory data and propose a method to identify the arterials based on such data.With the objective to cover as much traffic flow as possible,we established an integer-programming problem to obtain a number of disjoint paths as the arterials to be coordinated.By coordinated control of these arterials,it can reduce the overall travel time and average delay by a great extent.3.We study the iterative optimization algorithm of signal timing based on sampling trajectory data.It includes the optimization method of the cycle length,the green split and the offset of single intersections and arterials.We use the delay evaluation index to make the optimization measurement decision.The algorithm is simple and easy to implement.Through iterative optimization,it can reduce the average delay and improve the efficiency of the whole road network.4.The simulation framework is established and the iterative signal timing optimization algorithm is realized in the simulation.We compared the results of three different optimization scenarios,and verified the effectiveness of the proposed algorithm.The average delay of the road network is decreased by 35%,43% and 48% under the three scenarios.The results showed that the algorithm is most effective in improving the traffic performance of the road network among the three scenarios.