An important development has been the acquisition of vehicle mileage information from UK data for individual vehicles, and more recently from Sweden. This information provides a direct measure of mileage effects on vehicle emissions. Considering the whole dataset, containing almost 1 million vehicle measurements in total, mileage deterioration factors have been derived that show the change in emissions at 0, 50,000, 100,000 and 200,000 km for petrol and diesel cars, separated from the influence of VSP and ambient temperature on emissions. For emissions of CO and NOx from petrol vehicles the data show increasing emissions with increased mileage, with earlier Euro standards showing more deterioration. The trends in HC with mileage are mixed, with Euro 3 and 4 vehicles showing a decrease in emissions with age. There is evidence that the emission of CO and HC increase as diesel passenger car mileage increases. The quantification of HC from Euro 6 vehicles by means of remote sensing is more uncertain. Emissions of NOx from Euro 5 and 6 diesel vehicles show no obvious change as the vehicle mileage increases and there is limited evidence of an increase for Euro 3 and 4 vehicles at high mileages up to 200,000 km.
Den här rapporten finns endast på engelska.