[jessriedel]

But you can imagine an internal AI that can tell whether it's being watched by the government with arbitrarily sophisticated means. In fact, that's just an extreme example of how VW broke rules. It wasn't, as I think you might be imagining, a case where the emission measuring device was lazy and just took the car's word for it. Rather, the car's software determined that it was being tested (based, I think, on various cues from how it was being driven), and lowers emissions in those situations.

[anon4]

Or even simpler: if $INTERNAL_CLOCK < $PROJECTED_DATE_OF_SALE { fake_emissions; }

[jessriedel]

Many states in the US force you to test emissions when you register your car.

[DrQuack]

if(miles_driven < 10,000) { fake emissions; }

[jessriedel]

You often have to renew this every few years, or when you move to a new state. Even my 16-year-old Chevy Caprice with 200k+ miles had to run the CA gauntlet.

[TeMPOraL]

  (unless (car-radio-playing?) ; probably not the owner driving
    (fake-emissions))

[TearsInTheRain]

I mean that would be a pretty crappy defeat device