The accident happened around 6:00 a.m. at the intersection of 15th and Chestnut Streets in Center City Philadelphia - just two blocks away from a large evacuation scene due to a carbon monoxide scare at an Art Institute of Philadelphia dormitory.
Investigators say the bus was detoured because of that evacuation.
The exact cause of the crash remains under investigation.
Six people on the bus were taken to the hospital with non-life threatening injuries.
The Route 21 bus is now back to normal.
