Research On Optimizing The Initial Setting Of Directional Lane

The traffic operation efficiency of the bottleneck section in the urban road network during peak hours is very important for the traffic operation state of the urban road network.In order to improve the traffic operation efficiency of congested section of urban road network during peak hours,some experts have proposed the ‘directional lane’ control technology,by specifying the direction of vehicle movement in the ‘directional lane’ and prohibiting lane changes,the lane change behavior of the bottleneck section is reduced.Average speed of the traffic flow in the ‘directional lane’ is increased,traffic interference of the traffic flow in each lane is reduced,and the traffic efficiency of the bottleneck section during peak hours is improved.However,after setting the directional lane,although the overall traffic efficiency of the bottleneck section during peak hours has been significantly improved,the traffic turbulence in upstream section of the bottleneck point has increased,vehicle parking times and delays have increased.It is found that this is due to the unreasonable setting of the beginning of the directional lane.To solve this problem,this essay will study the optimization of setting beginning of the ‘directional lane’.In the first step,the definition,setting conditions,purpose and significance of setting the ‘directional lane’ are described.Then take the Egongyan Bridge as an example,based on the measured traffic flow data,analyze the traffic operation characteristics of different lanes during the peak after setting the ‘directional lanes’,including traffic volume,average speed and headway.Then the distribution function of the headway’s time interval is fitted and analyzed.Through data analysis,it can be seen that the lane-changing vehicles will gather in the upstream section of the lane where the directional lane is located during peak hours,resulting in an increase in the traffic density of the lane and a decrease in the speed of traffic flow;at the same time,the number of vehicles changing lanes in the traffic flow increases,and a large number of continuous crossings occur lanechanging behavior in multiple lanes.In the second step,corresponding optimization measures are proposed for different application scenarios of the beginning of the directional lane.When the starting end of the directional lane is set on the road segment or upstream of the main line-ramp confluence nose,based on the gradual evolution of the traffic flow status of each lane,analyze and calculate the delays experienced by vehicles with different running trajectories in each lane and the total delay of traffic flow,to build an optimized model of the directional lane starting point forecast distance,ensuring that a certain percentage of lane-changing vehicles have sufficient time to safely and successfully change lanes,and at the same time balance the traffic flow distribution of each lane of the upstream section of the beginning of the directional lane,improve the traffic flow of the road.When the starting point of the directional lane is set downstream of the main line-ramp confluence nose,based on the traffic operation characteristics,influencing factors and traffic capacity of the upstream confluence zone at the beginning of the directional lane,a following and lane-change rule for the confluence zone is constructed,to study the influence of the merge length on the capacity of the merge area under the condition that other factors remain unchanged,and determine the optimal merge length and the optimal location of the directional lane starting point when the capacity of the merge area is maximum.In the last step,based on the actual traffic data of Egongyan Bridge,an example analysis is carried out,and the grid search algorithm is used to solve the optimal forecast distance of the starting point of the directional lane under different traffic conditions.The optimal forecast distance when the starting point of the directional lane is set upstream of the road section or confluence area is 750 m.When the starting point of the directional lane is set downstream of the confluence area,the optimal setting position is 150 m from the confluence nose.Through the above research,based on the influence of directional lanes on the traffic operation of the upstream section of the bottleneck point,the optimization measures set at the beginning of directional lanes in different application scenarios are studied,which is of great significance to the promotion and application of directional lanes and the formulation of relevant standards.