According to the European Environmental Agency, European citizens often breathe air that does not meet European standards. Indeed, air pollution is the main environmental risk factor of premature deaths: in 2011, 430,000 premature deaths in EU-28 were attributable to a long-term exposure to excessive levels of fine particulate matter and 16,100 to short-term exposure to ozone (EEA, 2014). Besides its impact on health, air pollution also affects cognitive abilities and worker productivity. On average in the 33 member states of the European Environment Agency, the road transport sector is the main emitter of nitrogen oxides (NOx), representing 37% of total emissions; and it is the second largest emitter of carbon monoxide (CO) emissions, with 19% of the total. Road traffic also contributes, to a lesser extent, to the emissions of particulate matter 2.5 and 10, and volatile organic compounds (VOC)1