Research On Vehicle Running Characteristics And Setting Of Climbing Lanes On Continuous Uphill Sections Of Expressways

Due to the limitation of topography,landform,geological conditions,environmental protection,engineering economy,construction technology and other factors,China’s expressways have to adopt larger longitudinal slope design indicators in the design,thus forming continuous uphill sections.Due to the insufficient power performance of the truck,it’s running speed on this road section drops sharply,and the road capacity,service level and traffic safety level decline.Scientific and reasonable setting of climbing lanes can improve the above problems to a certain extent.This paper takes the continuous uphill section as the research object,and the main work and results are as follows:(1)Based on the measured data,the operation characteristics of large and small vehicles on uphill sections are analyzed:within the allowable conditions,the large longitudinal slope and slope length have little impact on the operation speed of passenger cars,but the operation speed of trucks decreases significantly after driving into uphill sections.After the driver changes gears to improve the dynamic performance of vehicles.Finally,it reaches a stable operation state.(2)Comprehensively considering the development status and development trend of China’s trucks,determine Six-axle semi-trailer as the leading models of longitudinal slope design.Applying the principle of automobile dynamics and using the technical performance parameters of the leading model,the parameters of the leading model,such as the maximum speed,critical speed,shifting speed,balance slope length and balance slope,are theoretically calculated.Based on the running speed at the bottom of the slope that meets the engineering reliability and the speed reduction amount that meets the traffic safety,the starting position of the climbing lane under different road and traffic conditions is obtained by calculation,and the setting method of the climbing lane is improved.(3)From the perspectives of traffic capacity,service level and traffic safety,the influencing factors of setting up climbing lanes on longitudinal slope sections are analyzed.Proposed Capacity Improvement Rate,Speed Standard Deviation,and Speed Standard Deviation Coefficient as evaluation indicators.Using VISSIM software as the simulation platform.the simulation parameters are calibrated based on the actual traffic conditions of highways,and a scientific and reasonable simulation model is constructed.Combined with the research results and related specifications of this paper,the design scheme of the climbing lane for the continuous uphill section of the Yong Ling Expressway in Hunan Province is determined,the feasibility of the scheme is analyzed by means of simulation.The effectiveness of the climbing lane under different road and trafic conditions is studied to improves the setting conditions of the climbing lane.Based on the traffic status of the continuous uphill sections of highways in my country,the setting methods and conditions of the climbing lanes are studied,and the climbing lanes are set up scientifically and reasonably to give full play to their expected functions.The research results are expected to provide theoretical reference for engineering project decision-making.