States that do safety inspections are generally more thorough.

Virginia: https://vsp.virginia.gov/safety-and-enforcement/vehicle-safe...

Massachusetts: https://www.mavehiclecheck.com/motorists-basicinfo#Safety

Those are the only two states I've lived in. I don't get why so much of the country doesn't do these; it seems the Northeast of the US almost all require periodic safety inspections and the western US does not.

At least where I have lived if there is an emissions check it is a separate test. I think the inspections I have had to do involve brakes, lights, steering/tie rod, windows (no cracks/chips), exhaust, and I think in VA the engine light could only be on for frivolous things.