Comment by h3half

There’s also the fact that nearly 1/4 US states require no emissions or safety checks whatsoever [1]. So everything is valid by default and realistically the only thing stopping you from driving a literal rust bucket, with tailpipe dragging, poor combustion, or modified emissions filtering (like modifying your truck so you can roll coal down Main Street) is it a cop feels like pulling you over for it

[1]: https://goodcar.com/car-ownership/vehicle-inspections-by-sta...