(CNN) -- The state of New Jersey is imposing harsher restrictions on Ferris wheel safety after an 11-year-old rider fell to her death earlier this month.
Officials are mandating riders be at least 54 inches to ride without supervision, according to a letter from Michael Triplett of the New Jersey Carnival and Amusement Ride Safety Unit.
Triplett also "strongly recommended" that each car have at least two riders, and added that if a manufacturer has a more strict requirement, that requirement should be followed.
The changes coincide with the release of a preliminary report into the death of Abiah Jones of Pleasantville, New Jersey, who fell at Morey's Piers Mariner's Landing Pier, in Wildwood, on June 3.
Jones, who met a 54-inch height requirement, was on a school trip when she fell from one of the park's main attractions, called The Great Wheel. After receiving first aid at the scene, she was taken to Cape Regional Medical Center, where she was pronounced dead.
How the girl fell is still undetermined, and officials have no eyewitnesses, according to a report by the state of New Jersey. Surveillance footage showed her during the fall but did not show her leaving the gondola, the report said.
It determined she entered the ride as a single rider and sustained "significant head trauma as well as cuts on her arms and shoulders," hitting several objects on her way to the ground.
The findings also concluded operators had no knowledge of any problems, the ride had no mechanical defects, and no other problems had been reported in its 25-year history.
"The fact that Abiah Jones was alone in the gondola, without any nearby passengers, may have led her to take a risk that she would have been convinced not to take if there were other riders in the gondola," the state investigator concluded.
At 156 feet, the ride is one of the tallest wheels on the East Coast, Morey Piers spokeswoman Lindsey Young told CNN.