A Greyhound bus turned over onto its roof early Saturday while traveling through southern Ohio, authorities said.
At least 34 people who were on board the bus were taken to hospitals, six of them by helicopter, said Butler County emergency management spokesman Jeff Galloway.
The bus originated in Cincinnati and was heading to Detroit.
The bus was carrying 52 people when it overturned about 26 miles north of Cincinnati just before 4 a.m., he said.
I-75 was shutdown from S.R. 129 to S.R. 63 for a period of time after the accident.
Occupants were trapped in the bus before they were rescued by fire and EMS crews, reports WLWT News Cincinnati.
Adrian Warren is a 19-year-old student at Tennessee State University. He was taking the bus home to Detroit to see family for the weekend.
Warren told Local 4 he was sitting on the right side of the bus when it flipped over to the left side. Luckily, he only suffered minor cuts to the hands.
"A woman was screaming, wake up, wake up. The next thing I know the driver was slumped over," said Warren. "The next thing I know we're running off the road and there was a bunch of turbulence, and the next thing I know is we are flipping two or three times."
Adrian and a few other passengers scrambled to find the exits and help the injured get off the bus. He was happy he was not injured.
"It happened so quick. It's still like a shock to me," Warren said. "I'm just glad I made it out alive."
Warren's parents opted to pick him up in Ohio.
Other passengers who were not injured were transported back to Cincinnati on another bus.
Warren said he believes the driver had a medical emergency. Officially, the cause of the crash remains under investigation.