A bit&#x2F;lot of it may be &quot;optimize for the test&quot;, not cheat. They know at what temperature the test is done, so they optimize the chemistry for that case. They know it will be done with new cars, so they do not optimize &quot;emission over the car&#x27;s lifetime&quot;.<p>They also have drivers who are above average. That will help with manually shifted cars.<p>And of course, they pick the best car they can produce, and prepare it optimally. Tyre pressure will be optimized, the car will be perfectly polished, if that helps, etc.<p>Cheating starts when they tape shut doors to decrease air resistance, or when they explicitly detect &quot;test is being run&quot; and act upon it.<p>IMO, the real problem is twofold: firstly, the existing tests were designed in such a way that their results do not reflect what happens in the real world, and secondly, some manufacturers went criminally far in optimizing for it.