Research On Real-time Dynamic Reversible Lane In Intelligent Vehicle Infrastructure Cooperative System

In the process of urbanization,although the construction of urban traffic infrastructure changes quickly,the supply of urban road resources is still limited,which often fails to keep up with the increase of traffic demand,thus resulting in prominent contradiction between traffic supply and demand and serious urban traffic congestion.It has become a major issue restricting the healthy and sustainable development of the city.In the case of limited supply of urban road resources,it is a workable way to make supply-side reform on transportation resources by making full use of the existing road traffic resources through new technologies and management methods to improve the traffic capacity and efficiency.The deep reason for considerable part of urban traffic congestion is mainly the traffic flow directional supply-demand imbalance,that is,the traffic flow ratio of all directions of road sections or intersections presents significant differences in different periods,which causes the dislocation of resources supply and demand,and the sharp decline of traffic efficiency.Reversible traffic management is an important approach to solve the problem.However,the current research and application of reversible lane mainly focus on the scheme of fixed time and fixed section reversible lane,which can not adapt to the real-time change of traffic flow actively and the resource utilization efficiency is low.At the intersection,the state is shown as the non-equilibrium between different turning traffic flow at the entrance,and it is shown as the non-symmetry between the bidirectional traffic flow at the road section.Due to the rapid development of Intelligent Vehicle Infrastructure Cooperative System(IVICS),it is possible to understand the imbalance between supply and demand of traffic flow in real time and adjust the reversible lane control strategy dynamically.It is a research work with great theoretical and practical value to systematically explore the control theory and method of real-time dynamic reversible lane in the IVICS.Firstly,basing on defining the traffic flow directional supply-demand imbalance,the paper establishes the feature expression models of supply-demand imbalance at intersection,arterial and network level respectively combining with the survey data of urban road network,which reveals the evolution characteristics of the traffic flow directional supply-demand imbalance,and defines the application scenario of real-time dynamic reversible lane.Then,through the comparison and verification of the prediction results with the actual data,the modified GA-NARX neural network model is proposed to predict the traffic flow,which provides the basis for grasping the traffic flow directional supply-demand imbalance trend.Secondly,referring to the relevant implementation standards of reversible lane,the paper summarizes the conditions and principles of setting real-time dynamic reversible lane,and constructs the overall scheme of real-time dynamic reversible lane mainly from hardware operation facilities,operation organization and information control support.The facility system with intelligent road stud as the core and related facilities layout scheme are proposed.The reversible lane operation process is designed and the reversible lane operation and safety control scheme are constructed from time,space and IVICS.The implementation and lane allocation schemes of the reversible lane are put forward from lane switching number,opportunity and process.By analyzing the requirements of information support of real-time dynamic reversible lane,the setting scheme of control information system in IVICS for reversible lane is put forward,which provides the technical scheme of information system for the cooperative control of real-time dynamic reversible lane.Thirdly,a cellular transmission model for the segmented opening of reversible lane is constructed according to the real-time dynamic reversible lane scheme.The evolution characteristics of traffic flow in the control process of reversible lane are analyzed,and the change rules of speed and density in the process of reversible lane switching are revealed,which provides support for the dynamic control of reversible lane.Based on the analysis of the switching time and influencing factors of the assignment scheme of reversible lane,the opening point and length of reversible lane are determined by detecting the congestion points of the arterial road,and the lane allocation model is built with the objective of minimizing the total impedance of the arterial road.In addition,the factors affecting the safe operation of reversible lane are summarized,and the safety control model and process of real-time dynamic reversible lanes at road section and intersection are constructed respectively,which provides guarantee for the safe operation of real-time dynamic reversible lane.Fourthly,the influence of reversible lane on the operation of intersection is analyzed by comparing the operation characteristics of intersection in traditional environment and IVICS.Then,the signal phase sequence and signal timing are designed for the cooperative control of the reversible guide lane and intersection signal.The function division scheme of the reversible guide lane is initially determined through the goal of maximizing the utilization rate of the space-time resources of the lane,and then finally determined by the traffic capacity and vehicle delay.In order to maximize the resource utilization of intersections and link up the traffic flow operation of sections and intersections efficiently,the vehicle merging optimization model,speed guidance model and signal timing collaborative optimization model for reversible lane are constructed respectively.And then the dynamic control process and method of reversible lane for single intersection are proposed,which realizes the optimal allocation of space-time resources of dynamic reversible lane at single intersection.Fifthly,the paper analyzes the operation characteristics of traffic flow on arterial road in IVICS to support the real-time dynamic reversible lane control.According to the principle of subsection optimization control,the length of the reversible lane segment is determined with the goal of optimal lane utilization efficiency.And the control methods on clearing and opening the reversible lane are proposed,the control process of clearing reversible lane,speed guidance strategy for clearing and speed guidance strategy for arterial road cooperative operation are designed.The collaborative optimization model of green wave phase difference of the arterial line is constructed,and the cooperative optimal control process for the real-time dynamic reversible lane on arterial road is formed.Finally,the cellular transmission simulation models of single intersection,road section and arterial road are constructed for West Beijing Road in Nanjing.The dynamic switching scheme of reversible lane and the signal timing scheme are optimized through the optimization control model proposed above.The comparison results on traffic operation state before and after optimization show that both the average speed and congestion duration of the real-time dynamic reversible lane scheme are significantly improved than the condition of non-opening reversible lane and conventional reversible lane in the fixed time open state,which indicates that the models proposed in the paper could effectively improve the traffic efficiency of road sections and intersections,and fully verifies the effectiveness of the scheme and intelligent optimization control methods proposed for solving the traffic flow directional supply-demand imbalance.The implementation of real-time dynamic reversible lane is affected by many factors such as scheme,facilities,technology and operation environment,etc.Only the cooperation of these factors could make full use of its role,and truly achieve the purpose of alleviating the traffic flow directional supply-demand imbalance.Focusing on the implementation of real-time dynamic reversible lane,the paper studies the overall scheme design,traffic situation prediction,information management and control system construction,control model and method exploration,and forms a set of relatively complete theory and method on real-time dynamic reversilbe lane application,which provides idea and reference for the development of reversible traffic management in IVICS.