02/11/2012 03:53 EST | Updated 04/12/2012 05:12 EDT

Mounties rule out road conditions, drugs and alcohol as causes in bus rollover

REDWATER, Alta. - Investigators say road conditions were not a factor in a terrifying bus rollover in northern Alberta, while the company that operated the vehicle says the driver was an experienced veteran.

No one was killed when the Red Arrow passenger bus crashed on Highway 28 between Edmonton and Fort McMurray on Friday, but Alberta Health Services said at the time that three of the people on board were listed in critical condition. There was no immediate update on their condition Saturday.

RCMP say 37 people were on board and that five people had to be extricated from the bus.

John Stepovy, the general manager of Red Arrow, said the driver had been a bus operator for many years and was familiar with the road where the accident happened.

Police say they have also ruled out drugs or alcohol as factors, but say the exact cause is still under investigation.

Stepovy said the company is doing everything it can to assist the injured passengers, some of whom have already been released from hospital.

"It's not something we ever wished for that's for sure. It's an unfortunate incident," Stepovy told CFCW radio in Edmonton.

"Our main objective is to take care of those passengers affected and be there for them and their family."

Passengers described the road as being clear and dry, but they said the bus wobbled and went out of control on a curve.

One man described seeing fellow passengers scraped across the pavement before the bus finally came to a stop.

Alberta Health Services said privacy rules prevented it from providing updates on the injured passengers' conditions.

Police, however, said in a news release Saturday that no one had died and that injuries still ranged from serious to minor.