It happened around 7:00 a.m. on westbound Route 40 near Route 896.
Investigators say the school bus driver, 78-year-old Woodrow Parson of New Castle, was heading to Hodgson Vo-Tech School when he failed to stop and hit the rear of a Honda Civic.
The Honda was pushed forward and hit the back of a Nissan Maxima.
The 17-year-old driver of the Nissan was taken to the hospital to be treated for head, neck and back injuries.
A 15-year-old on the bus was treated and released from the hospital.
There were no other injuries.
Parson was cited for following too close.
Route 40 westbound was closed to traffic for approximately 45 minutes as the crash was investigated and cleared.