One of my criteria for choosing an area to live in is emission testing. After growing up in California and dealing with their inane smog laws, I swore to never live again in a county that required testing.
We did live in Ogden, UT for several years. They had emission testing back then- but the fair kind . By that I mean that they sniff the tailpipe and it's pass or fail. At the time I had a Bronco with a fuel injected 302. Cammed, remapped fuel curve, no catalytic converters- yet it passed the tailpipe sniff. Because it ran great! They knew all the mods I did but they didn't care because the tailpipe was clean.
Now in CA, I spent years trying to outsmart the emissions testing. What got me was the time I had a vehicle that passed the sniff test but failed the visual. I had to spend $800 to reinstall a bunch of emissions equipment. On retest, it failed badly. So I got a waiver for that registration period because of the money I spent (wasted). But if I couldn't bring the emissions into spec I could not renew my registration the next time. So- not only did I waste $800 but the fuel economy dropped by a large amount. So you have a law written to clean the air- a good thing. Yet the way it's written it does the opposite, and encourages what they really want- everyone to buy newer cars. By the way- California also taxes registration like homeowners property tax- on the book value of the car. So if they make you buy a newer cars, the state makes more tax income on registrations. California sucks. Period. It's a shame they have some of the best weather, scenery, and recreational areas. But I'll never move back!