The accident occurred when the driver of the van, Jerry Leishman, 40, of Falling Waters, W.Va., slowed down in the left-hand lane as he headed south. Leishman told police that his van was shaking because his tire was going flat and that he was trying to pull over.
The tractor-trailer driver, however, said he thought Leishman was trying to do an illegal U-turn. The tractor-trailer driver - Jeffrey S. Holt of Las Vegas - collided with the back right side of the van, Folk said.
Pushed by the tractor-trailer, the van flipped and came to rest upright in the right-hand northbound lane. No cars collided with it, Folk said.
After hitting the van, a front tire on the tractor-trailer's cab blew and it too crossed the median, crashing through a cable barrier, Folk said.
As the woman in the Cavalier headed north, the front end of her car was run over by the truck's box trailer, Folk said. Although Folk said he did not know what the truck was hauling, he said its box trailer was nearly full and heavy.
One witness said it appeared as if one of the van's tires was going flat, while another said it looked as if the driver of the van was trying to do a U-turn, Folk said.
All of the rubber on one of the van's tires was shredded, Folk said.
Both Holt and Leishman were treated at City Hospital and released, Folk said.
Folk said the accident remained under investigation.
As a result of the wreck, police shut down the interstate and diverted northbound traffic from Exit 16 onto U.S. 11 north of Martinsburg.
Traffic on that two-lane road was backed up, and at times was nearly at a standstill in Martinsburg from drivers who tried to cut through town.