CASPER, Wyo. -- One person is dead and dozens are injured after a commercial bus from Denver crashed into a flipped-over tractor trailer in Wyoming on early Saturday morning.

The Wyoming Highway Patrol report the accident happened south of Casper, Wyo at around 1:40 a.m. and began when a tractor trailer lost control and flipped over.

After that accident, the northbound commercial bus, owned by Arrow Stage Lines, crashed into the sideways trailer, killing the bus driver instantly and injuring most of the 47 passengers on board.

The accident started when a tractor trailer operated by Darren Nelson Trucking out of Sioux Falls, S.D., slammed into the median on Interstate 25 and flipped over, according to a release by the Wyoming Highway Patrol. The truck blocked most of the two northbound lanes of I-25 after a steep incline.

The Arrow Stage Lines bus came to the scene a few minutes after the accident. The driver did not see the flipped over tractor trailer and slammed into it.

The impact pushed the truck 60 feet down the roadway before both vehicles came to a stop.

All of the bus passengers were transported to Wyoming Medical Center in Casper, Wyo.

Bruce Newharth, CEO of Arrow Stage Lines, confirmed the death of the bus driver. Newharth said the driver, who he refused to name, had been with the company since 2006 and had a very good driving record.

"He was an excellent driver," Newharth said. "He was great with customers."

Newarth said six passengers remained hospitalized but are not suffering from life-threatening injury. Newarth said the bus was driving one its regular routes from Denver to Billings, Mont.