Here in CT, we've fairly written the book on how not to administer an emissions program. I could go into all the lurid details of state ineptitude, corruption, and general mishandling of the program(s), but upon reading the details, it is likely the reader's head would explode. Just to throw a couple bone out there - When a vehicle in CT passed an emissions test, a decal was placed in the windshield to indicate the car had passed the test. Now comes the good part -- When the program started, every car in the state received a decal in the mail indicating that the vehicle had NOT yet been tested for emissions. Think about that one for a moment, then multiply it by eleven. Diesel cars were exempt, but they had to report to the station, and buy an emissions decal at full price. Clean air? Ha ha ha - smells like revenuers "same as it ever was" to me.
Whatever shell game and dollar amount within the usual threat of withholding highway funds the feds throw around when they want their way could likely have been supplanted 3 times over with the amount of money we in CT wasted upon the various incarnations of vehicle emissions, CT style. If I recall, we started and stopped four separate and dysfunctional emissions programs since it started.
The primary issue I have a hard time with is that the overwhelming majority of vehicles do pass, except for the vehicles of those who cannot afford a newer car, and so those of unfortunate financial circumstances take it between the eyes.
When you boil it down, an emissions test as administered to a modern car is basically to determine if the "Check Engine" light is functional.
Thank God we don't get ALL the government we're paying for.
