Modelling vehicle emissions for Australian conditions

摘要

Traffic-simulation models are able to predict emissions for different traffic conditions based on algorithms calibrated with mainly European vehicle data. Such estimates are not likely to reflect Australian conditions, given the significant differences in vehicle fleet composition in terms of vehicle characteristics, age and fuel type used. This paper investigates the current gap between estimated emissions and actual measurements using an Australian emissions dataset. To estimate emissions a micro-scale vehicle emission model, integrated in AIMSUN, the widely used simulation modelling software, was used. The pollution emission model calculates CO_2, NO_x, PM_(10) and VOC emissions from instantaneous speed and acceleration. The results presented here indicate that the model adequately predicts CO_2 emissions. However, the likely errors associated with the prediction of other pollutants are significantly greater. As a result, the paper puts forward improved emissions estimation relationships for use with micro-simulation models. Using Australian emissions data, it is possible to improve the estimation ability of those models. The results shown here highlight the need for further work to quantify the uncertainty attached to the inputs and the outputs of traffic-simulation models, in order to improve predictions of pollutants other than CO_2.