They also show most manufacturers switch off or turn down their emission control technologies at temperatures and conditions outside of the lab test without rigorous justification. More suspiciously, most cars in Europe emit much more pollution after a hot engine restart compared to a cold one demanded by the EU law – in contrast to in the US.
A much more comprehensive investigation must now take place to force carmakers to come clean and require a revamp of emission strategies used. Stricter and clearer guidelines on the use of exemptions from the defeat device ban are equally necessary. But all this must be accompanied by a rigorous reform of the EU testing system which is in dire need of more independent checks on the road, oversight of national regulators, and transparency.