Police say passengers were entering and exiting the bus on the right shoulder of New Castle Avenue southbound, at Ryan Avenue, when the accident happened about 8:30 p.m. Monday.
Authorities say 15 people were taken to hospitals for treatment of minor injuries or an evaluation.
The driver of the van, 62-year-old Earl R. Henry of New Castle, was cited for inattentive driving.
The roadway was closed for about 1 ? hours while the crash was investigated and cleared.