State Police Sgt. Brian Polite says the crash happened just after 6 p.m. Monday in Oldmans Township, about 25 miles south of Philadelphia.
Three adults were trapped in the burning car and pronounced dead at the scene. Polite identified them as 24-year-old Manuel Marshal of Cheverly, Md., 27-year-old Jessie Jones of Lanham, Md., and Arthur Briscoe, whose age and hometown weren't immediately available.
Polite credited two bystanders with saving the life of Jones' son, Hakeem, by pulling him from the car. The boy was flown to Philadelphia Children's Hospital, where he was listed in stable condition with a broken femur.