I was always told that the only way to test the vehicle for NOX was under load and that meant a dyno test. What’s their answer to this down south, for not doing a dyno test?
Here In New Jersey, they do a load dyno test. Where an inspection employee runs the car at 2500 rpm's while the tires spin on dual rollers. I think this is really the only fair way to get a true NOX reading.
From what I here Florida needs your mobile smog patrol since they lack an inspection system. If New Jersey didn't have the inspections our roads would be more of a nightmare, with dead cars and traffic jams.