Recently the new CLS was unveiled at the LA Auto Show: the first model series from Daimler to be routinely certified according to the Euro 6d TEMP standard and therefore the new "WLTP" (Worldwide Harmonized Light Vehicles Test Procedure) test procedure. Reason enough to take a closer look at the issue of certification. We're deliberately starting at the very beginning, because, in the public debate around consumption and emissions, little attention has been paid to the "How actually?" and the "What exactly?".