Ride safety and inspection requirements vary quite a bit from state to state, unfortunately. Some states do a pretty good job. Some don’t regulate rides at all.
In Colorado the job falls to the state’s “Division of Oil and Public Safety.” I don’t know their track record but the division’s name may give some indication of what their higher priority is.
In many states the job falls under the department of agriculture, I guess because of the historic connection to county fairs.
I’ll add that, while it’s absolutely appropriate to have strong state oversight to help keep the amusement parks safe, there’s only so much that the state can do to prevent accidents as they obviously aren’t going to be on site every day. When a park is found to have violated some regulation they can get fined thousands of dollars, but when they’ve been found liable for injuring or killing a guest they (or their insurance company) can lose millions in court, not to mention the reputational hit.