AFAIK car emissions are still only regulated during the LA City Traffic driving cycle at low and “high” (Denver) altitudes. Not on the highway except for fuel economy on the highway cycle.
That is essentially correct, but the government’s position is that VW was committing a crime each time the system switched off emissions systems at speed since it was ‘disabling installed emissions control systems.’
Of course, it was also enabling those installed emissions control systems when the car slowed down again.
I honestly think that VW made a huge mistake in not fighting this tooth and nail. It would have been far cheaper than rolling over and playing dead to US regulators who will have a field day making VW come up with an expansive recall scheme, punishing them for the original violation, punishing them again for driver’s not choosing to have their cars neutered, punishing them a third time for enabling these ‘scofflaws’ who choose not to have their cars damaged... It was a gift that regulators will enjoy for many many years to come.
Wrongo, bwana: emissions are regulated at all times; they're only "tested" on a driving cycle, but you sure as the dickens can't make the emission control strategy only function during the test!
American Motors tried that back around 1970 and got their you-know-whats whacked big-time.