The world’s fastest-accelerating roller coaster has been taken out of service because it’s been breaking the bones of its riders.

Since December, at least six riders sustained bone fractures after riding “Do-Dodonpa,” a roller coaster that goes at “super death” speed in the country’s popular Fuji-Q Highland Park, the park’s operator said.

The ride apparently goes from 0 to 112 miles per hour in just 1.56 seconds, which sounds awful. Investigators aren’t sure exactly what’s causing the injuries, which have included broken necks and backs. Yikes.