Control Optimization Method Of Intersections With Dynamic Use Of Exit-lanes For Left-turn Based On Traffic Flow Characteristics

The optimization methods of urban signal intersections includes signal control optimization and lane control optimization,etc.With the gradual increase of urban traffic volume,the demand for different turns in intersections increases,which seriously reduces the efficiency and capacity of traffic flow in intersections.In addition,due to the large number of conflicts of left-turn traffic flow in the intersection,the optimization control method for left-turn traffic flow is gradually developed.With the increased of traffic demands,although the traditional intersections organization optimization methods can solve many congestion problems,the optimization effect during the peak period of urban traffic flow is limited by the geometric space and signal control of the intersection.The limited intersections cannot further increase the capacity and operating efficiency of the intersection.In the exploration of improving the traffic capacity of intersections,the setting of reverse variable lanes of left-turn traffic greatly improves intersections.Therefore,it is necessary to optimize the organization mode of left-turn traffic flows according to the complicated traffic environment in China.The paper include three section: application condition of exit-lanes for left-turn at the signal intersection,traffic demand parameters analysis and optimal function.The applicable condition is the foundation of the exit-lanes for left-turn research,traffic flow parameters analysis and control optimization is the expansion and application of the applicable condition analysis.The main research objects of the applicable conditions analysis layer include the applicable conditions and running characteristics of reverse variable lane.In view of the operation mechanism of the left-turn vehicles include the reverse variable lane,the analysis of approach lanes condition,flow condition and signal control mode of the intersection.The revelent parameter are given.On this basis,by observing the process of using reverse variable lane for the actual left-turn traffic flow,this paper puts forward the possible safety risk of the left-turn traffic flow after setting up reverse variable lane and analyzes the risks of the reverse variable lane.In the section of the traffic flow parameters analysis is mainly analyzes the mutual interference degree,conflict characteristics,and modification of the traffic wave model from the perspective of time characteristics and space characteristics.In the left-turn flow conflicts analyse,the left-turn traffic trajectories are extracted in the reverse variable lane and the leftturn lane.The trajectories of the two traffic streams are analyzed based on the fitted trajectory distribution.In addition,it can get the conclusion of the left-turn traffic flow interferes with each other at different locations of the intersection.The degree of conflict in the left-turn traffic flow during the release phase is determined,the conflict area is determined,and the reverse variable lane is set through statistical analysis.The distribution of the rearward invasion time of the leftturning traffic at the exit of the intersection provides conflicting safety constraints for subsequent modeling.In terms of optimizing the left-turning traffic flows,according to the pre-signal control method of the reverse variable lane,the process of arrival and release of left-turn traffic is analyzed.In addition,a model of left-turn traffic waves for reverse variable lanes is established,which is based on the Logit model.The process of traffic flow release are analyzed and a left-turning traffic wave model of the reverse variable lane is established.Based on the Logit model,the left-turn vehicle's behaviors were modified and the parameters in the control optimization model below were optimized.In the section of control optimization is uses the conclusions of the applicable condition analysis layer and the traffic flow parameter analysis layer,and starts from the two aspects of time resource allocation and space resource allocation to establish a two-layer optimization model of reverse variable lane.The lower layer is the intersection optimization model,which including lanes attribute optimization,exit lanes and the signal control scheme.The upper layer is the reverse variable lane control model,including the setting time of the pre-signal,the reverse variable lane length optimization,and the corresponding constraint conditions.Finally,the optimization model proposed in this paper is compared with the conventional intersections.The corresponding case analysis are given based on the actual intersection environment.The multiobjective genetic algorithm is applied to signal control and traffic flow operations.Solve the bilevel programming model under constraints.In summary,the paper studies the operation mechanism of left-turning traffic flow after setting reverse variable lanes at signalized intersections.First,it studies the operating characteristics of left-turning traffic flow and analyzes the release of left-turning traffic flow in reverse variable lanes.Characteristics and conflict characteristics can be applied to a microscopic traffic flow simulation system suitable for China's traffic environment.Secondly,a left-turn traffic wave model and a left-turn traffic lanes selection model for reverse variable lanes are constructed,which can better serve our traffic effectiveness evaluation of left-turn traffic flow under the environment.Finally,a two-layer optimization model for reverse variable lanes was proposed to optimize the setting length,number of lanes,and signal control schemes of reverse variable lanes,and the validity of the research method was verified.