Study On The Influence Of Urban Expressway Traffic And Geometric Parameters On Vehicle Emission

The geometric linear design of the curve directly affects the exhaust emission of the motor vehicle.The circular curve section of expressway is an important component of the urban expressway network,and the traffic volume is large.But the existing research focuses on vehicle exhaust emissions at road sections and intersections.In this paper,a method for calculating the emission of motorized vehicles at circular curves is proposed,which can be quantified by the geometric linear curve of the curve.First of all,this paper carries out traffic investigation on four representative Expressway curve in Hefei,and establishes a vehicle speed prediction model with the parameter of road line type as the variable.Based on the prediction model of integrated mobile source emission(MOVES),the prediction model of vehicle exhaust emission factor of Hefei expressway is obtained.Secondly,the collected data of driving conditions are analyzed in this paper.And The specific power distribution of motor vehicles is analyzed in different road traffic environments.Finally,the relationship between different specific power intervals and vehicle emission rate is used to calculate the emission rates of different vehicles under different traffic environments.Motor vehicle exhaust emissions on the circular curve of expressway is calculated,the calculation method that the expressway circular curve is divided into many small curved section makes full use of the curve radius,traffic density,vehicle composition,sectional average speed,standard deviation,and the speed distribution of traffic characteristics.The results are more accurate.Finally,the influence of the traffic density and the bend radius of the expressway on the exhaust emission is analyzed.This method can calculate the total emission of vehicle pollution according to the curve line design document and can be used in the evaluation of road exhaust emission during road design and road environment evaluation.In addition,It can be used as a reference for controlling traffic pollution and taking corresponding countermeasures,and provide support for urban traffic low carbon design.