In the Dutch municipality of Hillegom, work is currently underway on improving the N208 highway, one of the aims being to comply with European air quality standards. To assess success, at the request of VMC Policy and Process Management NO2 and PM10 concentrations have been calculated at various locations along the N208. Using the CAR model, concentrations have been calculated not only for the current situation, but also for 2010, 2015 and 2020. The calculations, performed according to the relevant protocols, indicate no exceedances of limit values.