Manipulated and defect SCR-systems on Euro V and VI heavy-duty trucks lead to enhanced emissions of nitrogen oxides from the road traffic. The enhanced emissions from road traffic in Denmark lead to about 10 premature deaths in Denmark, as well as it enhances a number of other illnesses including cardiovascular and respiratory illnesses, diabetes and lung cancer. The total external costs in Denmark have been estimated to 1.3 billion DKK per year, which are related to enhanced emissions from road traffic in Denmark related to malfunctioning SCR-systems. These results are findings based on the many measurements conducted in the project forming the basis for model calculations with air quality models at DCE. The project has furthermore demonstrated that using the remote sensing method is an efficient method for identifying heavy-duty trucks for subsequent roadside control by the police. Combining measurements and roadside control makes it possible to focus the police resources towards controlling heavy-duty trucks with the highest likelihood of malfunctioning SCR-systems. Simultaneously, the combination of measurements and roadside control will have a preventive effect, since the measurements will make it possible to identify a much larger number of heavy-duty trucks with malfunctioning SCR-system than the police.