We had a similar program in British Columbia, called AirCare. Unfortunately, people realized that you could use solutions to flush impurities out of your engine, and then if you let your gas tank get close to empty then put a quarter tank of premium in, your car would burn cleaner and get you a pass, even if it would normally fail.
Eventually the program was scrapped, due to fewer cars failing (8%, down from 14%, which is still too high IMHO), and likely as a way of gaining political capital with the public in advance of an election.
I live in a big polluted city, and cycle most places. I use the car for the short season at weekends to go kayaking. It has so far passed the emissions test no problem.
Eventually the program was scrapped, due to fewer cars failing (8%, down from 14%, which is still too high IMHO), and likely as a way of gaining political capital with the public in advance of an election.