Most car modifications are stupid, at least the ones i hear about

Whenever a car or motorcycle passes by that makes a lot of sound, i'm always unsure of whether i should feel bad because the vehicle is obviously damaged, and the driver can't afford to get it fixed, so they have to live with the embarrassment of driving around in an obnoxiously loud vehicle

Or flip them off because they're an asshole that intentionally fucked up their exhaust because "haha car go vroom"

When a friend of mine said he was planning to do that yo his bike, the rest of us unanimously told him we would pour sugar in his gas tank if he did so

These are the guys that have fuck Greta stickers. I like my environment clean, fuck me right?

And the truck. At the cost of the owner.

I still don't understand the naming scheme Pro life, rolling coal... it's all in an attempt to make it seem better than it is

There are national emissions standards for manufacturers, and some states have additional, more restrictive measures. California basically sets the national standard by being more restrictive. If a manufacturer meets California's requirements they will be able to sell everywhere else in the US as well (this is a broad generalization with caveats but this is a Lemmy post not a thesis)

For vehicle owners vehicle registration requirements vary greatly from state to state. Some states include annual emissions checks with random testing as well. Failing these tests means your vehicle cannot be legally driven on the road. Other states only inspect when the vehicle is initially registered, and only check for the minimum items, such as working lights and a clean title (vehicle titles can be declared "salvage" if they are involved in an accident, and the vehicle goes through a more rigorous inspection to have the title cleared).

The US has been in regulatory capture for… probably longer than I've been alive. States like California are doing the heavy lifting when it comes to regulation. The national government is so beholden to corporate interests that the only reason there are still national regulatory agencies with enforcement authority at all is because the national government is too dysfunctional to change anything. This is life in a burgeoning oligarchy.