The accident happened today morning on Interstate 70 near Richmond, which is about 113 kilometers east of Indianapolis and 56 kilometers west of Dayton, Ohio, where it planned to make a stop.
Authorities temporarily closed all lanes of the highway before reopening them about three hours later.
The cause of the collision was being investigated. Wayne County spokesman Jonathan Duke said one person was reportedly killed and 18 others were taken by ambulance or helicopter to hospitals. He didn't know the extent of the injuries.
About 20 injured people were taken to Reid Memorial Hospital in Richmond, including many who were treated for minor injuries such as cuts, scrapes and bruises, hospital spokesman Larry Price said. About half of them had already been discharged.
"I would describe them as walking and wounded," Price said. "At last check it didn't appear that we were going to have to admit someone."
She said that vehicle was so badly flattened that she couldn't see its wheels or whether it had been a car or truck.
"I've seen a lot of accidents, and I've never seen anything like this," Schroeder told The Associated Press.
The bus, which was traveling from St. Louis to Dayton, Ohio, and ultimately to New York City, was carrying 24 passengers and the driver, Greyhound spokeswoman Alexandria Pedrini said. Two new buses were dispatched to Richmond for the passengers, she said.
