Here in Colorado and probably in most other places, we have to take our cars in periodically and have the emissions levels checked. This service adds another $25 to the price of renewing your license plates which was doubled a while back to help pay for Denver mayor Webb's Toy Train Set. Ostensibly the check is to help keep the local air cleaner and not to be an additional tax on your car, and when it was implemented, there were a significant number of older vehicles on the road that, yes, could have used a tune-up.
Today most of the pre-OBD cars are gone and pretty much everything made after 1980 has an ECU in it that monitors engine health and helpfully puts up an alarming signal on the dash if your car varies from the prescribed levels. Mine even bitches while continuing to meet the allowed pollution specs.
Channel 7 has asked some local mechanics about the efficacy of the tests since a number of people have had their cars fail the emission test even though nothing was subsequently found to be out of order. I had this experience some years back when I took my Triumph in for a check and initially flunked badly. Of course I could see this coming when the millennial whose job it was to drive the car on the dyno stalled it 4 times trying to get on to the machine. From there on his efforts to avoid another engine stall resulted in his driving the whole test on the acceleration pump of the 4-bbl carb fitted to the engine. It was also obvious to me that a stick shift was not anywhere near his comfort zone.
I was entitled to another test for free, having paid for the first one, so I took the car to another testing station where the V-8 engine raised no eyebrows at all and the tester drove the car like he owned it. Unsurprisingly it passed easily.
Though not specifically looked into, it sounded to me like a number of the test failures mentioned in the article could be easily attributed to "pilot error" on the part of the test drivers keeping in mind that erratic driving technique will worsen any vehicle's emissions. Beyond that, pretty much any car made after the introduction of electronic fuel injection has programming in it that lights up that "service engine soon" light if your car gets even a bit out of spec, so it would probably be safe to ditch the dyno-equipped warehouses we have now and simply check for the trouble lamp on the dashboard. Taking the bulb out is no longer an option as that will show up on a code reader, the whole process taking no more than 5 minutes.
BTW: The emissions program, like the red light cameras, is run by a private company that collects the money from the drivers and kicks back a percentage to the counties that subscribe to its service so it's not likely that the program will be going away any time soon. There's too much graft at stake.