Note how the VW emission scandal came to light thanks to US regulators. We often think of the EU being ahead of the game in this sort of thing, but European car emissions testers are private entities that compete for business. This creates an incentive to "cook the books" and give manufacturers an easy time. US regulators, on the other hand, are public entities and have no such incentive to be nice to the auto manufacturers. Hence, a stricter testing regime that uncovered a culture of corner-cutting and cheating that existed in VAG. Mark my words, VW will not be the last Euro manufacturer to have been found screwing with emissions data.