Question – Does the government have to approve a ride before it is built?
Not really, except for local zoning and building permits, like are required for any thing that is built.
As for the safety of the design, it depends on the state and the type of ride. There are some “codes” for rides, but not many. Most of the codes are informal and established by the designers of the rides – actually that is the way most things are done in this country, much more than most people think.
Some states have inspectors especially for rides, but they stay busy checking on the carnivals. Sometimes, it is just the local building inspectors, and they can only check on a few things about the rides, because they don’t know much about rides.
The main reason that the rides are safe is because the parks will only hire the best designers who have proven that they follow the highest standards in their designs. We all want to do our best, and we don’t want to ever see anyone get hurt. The designers and the parks would all be out of business real fast if people started getting hurt on the rides.
Besides, since it takes many engineers many months of working together to design a ride, how could an inspector from the government ever have time to check all those calculations and design decisions. It is not possible. That is why we have standards to be a licensed engineer, and why the engineers are so careful to check each other’s work.