Over the coming years, the EU will gradually introduce stricter new emissions regulations for heavy duty trucks and buses. The first tightening of emissions legislation will be implemented in 2006 with the introduction of Euro 4. With this step, emissions of nitrogen oxides and particulates will be reduced by 30 and 80 percent respectively. The next stage is Euro 5. It will come into force in 2009, when emissions of nitrogen oxides will be almost halved compared with Euro 4.