Photo/Illutration The looping roller coaster Do-Dodonpa at the Fuji-Q Highland amusement park in Fujiyoshida, Yamanashi Prefecture in 2017 (Provided by Fuji-Q Highland)

FUJIYOSHIDA, Yamanashi Prefecture--A looping roller coaster here near Mount Fuji has been shut down for inspection after four people on the ride sustained broken bones between December last year and Aug. 12.

Riders on the Do-Dodonpa roller coaster at the Fuji-Q Highland amusement park sustained fractures including in their necks, chest and backs, Yamanashi Prefecture announced on Aug. 20.

The park reported the string of incidents to the prefectural government and the transport ministry on Aug. 17 and they began an investigation into its office on Aug. 21.

In each accident between December 2020 and Aug. 12 when a rider was reported injured, the park notified the prefectural police.

But the park did not report the accidents to the prefectural government until Aug. 17, after the fourth accident occurred on Aug. 12, drawing the wrath of Yamanashi Governor Kotaro Nagasaki.

“I think that if they reported them earlier and took appropriate actions, some accidents could have been prevented,” Nagasaki said at an Aug. 20 news conference.

The Do-Dodonpa attraction opened in 2017 to replace another roller coaster, according to the park.

While most roller coasters ascend to a high position and then shoot down from there, accelerating through gravity, the roller coaster cars in Do-Dodonpa are propelled mechanically and hit a speed of 180 kph some 1.56 seconds after the ride starts.

The first accident on the ride occurred in December 2020, according to the prefectural government and the park.

A woman in her 30s who took the ride began to have pain after returning home from the park. She went to see a doctor and found out that she had fractured bones in her neck and chest, requiring two months to heal.

In May 2021, a man in his 40s sustained a compression fracture in his backbone, requiring one month to recover, and in July a woman in her 50s experienced fractures in her neck and backbone from riding the roller coaster.

Following each incident, the park staff checked the rails, roller coaster and equipment. After the third accident, they also checked the roller coaster's accelerating speed, but found no problems.

From the accounts of the injured riders, the park judged that the accidents occurred due to the riders' failure to take the proper precautions by not staying properly seated on the ride and continued its operations.

During the eight months when the injuries were reported, the total number of riders of the roller coaster was about 210,000.

On Aug. 12, when the fourth accident was reported, involving a man in his 30s who suffered a compression fracture in his neck, the park decided to suspend operations of the roller coaster and begin a full inspection of the attraction that day.

“The prefectural government told us that we should have reported it earlier. There were some gaps in understanding the situation among us,” a park official said. “We would like to respond to this matter more appropriately.”

Operators who manage recreational equipment or attractions are asked to report all serious accidents, according to the prefectural government, though they are not legally obligated to do so.

The park's Aug. 17 report to the prefectural government was the first on an accident resulting in injury for Do-Dodonpa.

An official of the prefecture said that the prefectural government made the report public out of concern for public safety.

“A string of accidents occurred, and we judged that they were serious cases, and so we announced them,” the official explained.

(This article was written by Katsumi Mitsugi and Tatsuhiko Yoshizawa.)