Upper Uwchlan police Chief John DeMarco says investigators believe the driver was going under the speed limit when the first-grader was struck Wednesday afternoon in Exton.
DeMarco says the student had just been dropped off when the bus apparently ran over the child.
DeMarco says the Pickering Valley Elementary School student was in critical condition Thursday morning at A.I. DuPont Children's Hospital in Delaware.
DeMarco says police are still investigating the crash.