The man was identified as Tyler Shepler of Muhlenberg Township in Berks County.
Investigators say Shepler was trying to steal a few pairs of jeans Thursday afternoon when security officers stopped him in the lobby of the store.
Police say he ran across the parking lot and through a grassy area onto the highway, where one car hit him and knocked him down and another car ran him over.
After he was hit, police said they found Shepler lying on the ground gasping.
He was taken to Reading Hospital, where he was pronounced dead a short time later.