Microscopic simulation parameter calibration of CMEM model for temporary maintenance zone

In order to ensure the accuracy of automobile exhaust emission calculation, the parameters of microscopic simulation model for temporary maintenance zone were calibrated.The temporary maintenance zone located on the Xuwei Highway in Henan Province was taken as example, the traffic data were measured through field investigation.The VISSIM traffic simulation model was built.According to the measured data, the macroscopic parameters of traffic volume and traffic composition were calibrated, the microscopic parameters such as desired speed, desired acceleration were calibrated by using the values of feature points.Four parameters of car-following model including headway time, following variation, threshold for entering following status and vibration acceleration were calibrated by using orthogonal test.According to the valid simulation results, the numerical relationship between the desired speed and the running speed was determined.The emission of automobile exhaust was calculated by using the CMEM model with valid simulated data, and the calculation formulae of emissions were put forward based on average speeds.Analysis result shows the simulated speeds only calibrated by using macroscopic parameters are apparently different from the measured speeds, and the averagerelative errors of speeds for passenger car and truck are 11.36% and 35.12%.Combined with microscopic parameters calibration, the average relative error between measured and simulated speeds is lower than 3%.The desired speeds are 1.270 and 1.165 times of running speeds for passenger car and truck.After calibration, the relative error of simulated and measured emissions is less than 7%, and the calibration effect of model is remarkable.