Helicopter sent to county bus crash

Air care is sent to a bus crash in Pendalton County this afternoon. The bus crashed at the intersection of routes 27 and 23. The bus colided into an oncoming vehicle at 3 pm. According to officials none of the students on the bus were killed or injured. But the woman and 17 year old student riding in the other vehicle were flown to the hospital, with no life threatening injusies. their names have not yet been released to the public. Why did the crash occur?