Passengers are restrained by a shoulder harness, as well as a secondary locking bar across their laps. Compressed air is used to actuate the shoulder harness, with a fail-safe mechanism which engages the shoulder harness in the event of power failure. The loss of compressed air also causes the shoulder harnesses to engage. In addition, the gondola's sides and roof are made up of closely spaced metal bars, allowing riders to see the world outside, while preventing anyone from falling out while the ride is in motion. Like most ride safety measures, these are only effective if safety and height restrictions are enforced. To date, the only deaths or severe injuries caused on a kamikaze ride have been caused by a failure to follow the height restrictions, or complacency on the part of the operator or deck personnel. Most carnivals, fairs, and amusement parks require riders to be at least 48 inches (122 cm) or taller.