Study On Operation Characteristics And Simulationof Climbing Vehicles In Mountain Secondary Road

Mountain highway is restricted by the geological terrain conditions and cost,the linear designer of the mountain highway use the larger grades andslopelength inevitably.Mountain two-lane secondary road plays an important role in connecting other grade highways and promoting the regional economic development,and undertakes a large number of passenger and cargo transportation function.In the uphill section,the moving slowly load-carrying vehicles cause the traffic capacity to declineand even traffic accidents.In order to ensure the traffic capacity and safety level of the highway,it is necessary to study the vehicle's operation characteristics in the uphill section of the mountain two-lane secondary road.The climbing lane has a unique role in improving the traffic capacity and safety level of the uphill section,and it is the main research object in this paper.Based on the analysis of the research actuality at home and abroad,this paper took the research on the climbing lane of the secondary road in Guizhou Province as the support project.Taking into account the running characteristics and traffic characteristics of the uphill section of mountain highway.Speed difference,saturation and the conflict between vehicles were analyzedand the basis of setting climbing lane of the two-lane secondary road in mountain areas were studied in this paper.Firstly,the vehicle operating characteristics and traffic safety factors in the uphill section of the mountain secondary road were analyzed in this paper.Because of the mountain two-lane secondary road linear designis restrained by topography and geomorphology,there are many longitudinal slope sections,which lead the driving characteristics of different vehicles is differentin the uphill road.According to the survey statistics the dominant type of load-carrying vehicle was determined.This paper analyzed the operation characteristics of load-carrying vehicles in the uphill section from the aspects of the slope gradient,slope length,the ratio of mass to power,and the initial velocity of the slope.The traffic flow of the uphill section is different from the straight road.The three traffic safety factors about the vehicle speed,traffic volume and traffic compositionof uphill sections were analyzed.Secondly,the simulation scheme was developed in the light of the longitudinal section of the secondary road in Guizhou Province and the operation of the load-carrying vehiclein the uphill section.The VISSIM simulation model was established,and the parameters of the model were calibrated on the basis of the investigation of the vehicle speed and traffic volume.Under different conditions,the saturation,large vehicle speed difference and the track of the vehicle in the uphill road were obtained before and after climbing lane setting.By using SSAM,the vehicle running track files were conducted for getting the conflict rate reduction of the uphill road.The reduction rate of traffic conflict rate was used as the evaluation index of the effect of climbing lane setting.The simulation resultwasanalyzed with SPSS and it was divided into four categories,which were excellent,good,medium and poor.Combination conditions in the excellent and good category were taken as the condition of setting up the climbing lane,which provided the guiding opinions for setting up climbing lane in the secondary road of mountainous area.Finally,the secondary highway(Liuzhi Street to Shibangou)of Guizhou Province S102 was taken as an experimental section to set up the climbing lane.The survey data was analyzedand the simulation model was established.The saturation and the track of the vehicle were obtained before andafter climbing lane setting.The conflict rate reduction of the highwaywas got through SSAMand the evaluation result was excellent.The feasibility of the basis on setting climbing lane in the two-lane secondary road of mountain areas was verified.