Research On Traffic Operation Model Simulation Of Closed Passing Lane Work Zone Of Two-way Four-lane Freeways

Under the condition of ensuring certain traffic efficiency in the freeways work zone,in order to improve the traffic safety level of the freeways work zone,this paper takes the four-lane freeways closed passing lane work zone as the research object,and uses the traffic simulation technology to investigate the traffic operation in the work zone and its traffic impact.First,through the field traffic survey,the traffic flow data of the four-lane freeways closed passing lane work zone was extracted,and the traffic volume and traffic composition in the work zone,the headway time distribution,the speeds,the vehicle lane change location distribution and the traffic capacity were analyzed.Then,using VISSIM software to construct the corresponding traffic model of the work zone,the vehicle's lane change position distribution was selected as the evaluation index of the model,and a series of driving behavior parameters were analyzed through sensitivity analysis,8 parameters to be calibrated were selected finally.Combined with the characteristics of the traffic model,The Genetic Algorithm for calibration of the work zone traffic model was designed,and the automatic calibration procedure of the model was designed using Visual Basic language.The test results showed that the model effect was in good agreement with the measured data.Finally,Based on the calibrated work zone traffic model,the simulation experiments under different traffic volume conditions and different traffic facility layout conditions were carried out,and from the perspective of traffic efficiency and traffic risk,the traffic impact of the work zone was evaluated and analyzed.The results of the study show that the distribution of lane changes is a unique traffic characteristic of the closed passing lane work zone,and it is necessary and effective to use it as the evaluation index of the model calibration.When the upstream traffic volume of the work zone reaches about 1100veh/h,the number of traffic conflicts increases sharply and the proportion of unsafe lane change is the largest.At the same time,the work zone has the maximum capacity,which is about 1130veh/h.As the distance from the starting position of the lane change to the upstream transition zone increases,the capacity of the work zone becomes larger,and the proportion of unsafe lane change changes roughly in inverse proportion.when the distance from the starting position of the lane change to the upstream transition zone was far enough,the number of traffic conflicts will reduced to zero.Finally it is concluded that when the work zone is under saturated traffic flow,the optimal starting position of the lane change to the upstream transition zone is 1000 m.when the speed limit value of the work zone is about 70km/h,the capacity reach the largest,and then the capacity decreases slightly.under saturated traffic flow,when the speed limit value of the work zone is about 60km/h,The total number of traffic conflicts in the work zone is relatively small.In summary,through the analysis of traffic operation characteristics and modeling simulation of the closed passing lane work zone,this paper reveals vehicle lane change location distribution rules and the influence of the work zone traffic volume,sign setting,speed limit value and other factors on the work zone traffic operation.This paper provides a reference for the setting of work zone and has certain theoretical significance and practical value.