Research On Variable Speed Limit In Expressway Construction Area Considering Speed Limit By Vehicle Type

With the increase in the number of cars and the road damage of early-built expressways in recent years,the demand for expressway reconstruction,expansion and maintenance has increased year by year.Due to the reduction of traffic lanes in the construction operation section,the stability of the vehicle speed on this section is significantly lower than that of the normal section,which seriously threatens road traffic safety and operation efficiency.Therefore,it is necessary to effectively control the speed of the construction section..At this stage,a uniform static speed limit method for all vehicles is used to control the speed of the construction section.However,due to the difference in the speed limit value of different vehicles in the general section of the expressway and the difference in the geometric size and power performance of different types of vehicles,Therefore,the uniform static speed limit method for the entire vehicle model cannot meet the speed limit requirements of different types of vehicles.At the same time,since the speed limit value of the uniform static speed limit for all models is mostly selected according to relevant specifications,it is difficult to apply to the complex and changeable driving environment of the construction section.Therefore,in view of the shortcomings of the same static speed limit method for all vehicle models,it is difficult to effectively control the speed of the construction section.This paper uses the dynamic speed limit method by vehicle type to make up for related shortcomings,so as to improve the driving safety and operation efficiency of the construction area.First of all,based on the theoretical analysis of the characteristics of the construction work area and the necessity of implementing variable speed limits,combined with the real traffic flow data of a Canadian highway,the paper analyzes the impact of variable speed limit control on traffic safety,traffic capacity,and basic The influence mechanism of the graph.Secondly,it compares and analyzes the applicability of macroscopic,microscopic and mesoscopic traffic flow models in variable speed limit control.Finally,the METANET traffic flow model with speed prediction as the core is selected as the basic model of this article,and the basic METANET model is limited by vehicle type.The deficiencies in speed,driver’s expected speed,and dynamic traffic flow velocity density equations have been improved;the unknown parameters in the model are calibrated based on the OLS method and the measured data of the K highway construction section,and proposed based on the temporal and spatial change characteristics of the METANET model The solution idea of the model is presented.Then,on the basis of clarifying the function principle and modeling ideas of variable speed limit control,a multi-objective control function integrating total travel time and total travel distance is proposed,combined with constraint conditions,a model solving method based on CA algorithm is proposed.Finally,based on the analysis of the traffic characteristics of the K-high-speed construction work area,this paper calibrates the relevant parameters required for the simulation and constructs the K-high-speed construction area simulation road section.Combined with the selected safety and efficiency indicators,the simulation results under the variable speed limit control and static speed limit control of different vehicle types are compared and analyzed.The results show that after implementing the variable speed limit control method proposed in this paper,the traffic safety and operation efficiency of the K highway construction section have been improved.