Five people died early Wednesday in a head-on crash between two cars on Interstate 16 west of Savannah.

Investigators were trying to determine what caused a westbound Ford Mustang to cross the median and smash into an oncoming Kia Soul in the eastbound lanes shortly before 6 a.m., just ahead of the morning rush of commuters heading to work in Savannah.

"We've still got a bunch of unanswered questions," said Sgt. 1st Class Chris Nease of the Georgia State Patrol. "We don't have anything standing out to us saying hey, this is why this happened."

The collision killed the Kia's driver, 66-year-old Judy Johnson Vincent, and her stepson, Ronnie Bruce White, 44. They left their home in rural Eden early Wednesday so Vincent could drive White 22 miles to Savannah, where he was to begin a new job with a roofer, said Donald Vincent, the woman's husband and White's father.

"He hadn't had a job in a while and my wife said she would take him to work," Vincent said. "I told her she needed to leave early because of the traffic going in and out of Savannah."

The collision also killed the Mustang's driver, identified as Aundrey Renar Douglas, 49, of Claxton, about 50 miles west of Savannah. Douglas' two passengers perished as well. The State Patrol identified them as Devon L. Mobley, 24, of Claxton and Willie James Braggs, 62, of neighboring Glennville.

The State Patrol said there were no survivors in either vehicle.

The cars collided head-on near the city of Pooler along a stretch of highway where the posted speed limit is 70 mph. Impact mangled both vehicles so badly, emergency responders had to use cutting tools to remove most of the bodies, said Chief Wade Simmons of the Pooler Fire Department.

"All five were killed basically instantly," Simmons said. "There were no viable patients at the scene when we arrived."

Donald Vincent said he tried calling his wife and son when he didn't hear from them by 6:45 a.m. Then he saw news of the crash. The State Patrol was saying two people were killed in a Kia Sport, the same car his wife drove.

"I said, Lord, that ain't good," Vincent said.

He said his wife of 29 years was a devout woman who attended functions at her Baptist church every Tuesday, Wednesday and Sunday. Vincent said he and his son enjoyed hunting and fishing together, as well as drinking beer in their backyard.

Nease said investigators hoped to speak with other motorists who witnessed the crash. He said he was unaware of any witnesses who had come forward Wednesday morning.

"There's a chance that nobody did see it," Nease said.

The deadly crash shut down all eastbound lanes of I-16 for several hours Wednesday. They reopened after the morning rush at about 9:40 a.m.

Two wrecks last year also killed five people apiece on I-16, an east-west route that connects Savannah and Macon across roughly 170 miles.

Five nursing students from Georgia Southern University in Statesboro died April 22, 2015, as they headed to work at a Savannah hospital when a tractor-trailer slammed into stop-and-go traffic backed up by an unrelated wreck. Less than a month later, another tractor-trailer smashed into two cars near the busy interchange where I-16 meets Interstate 95. Five people perished in that wreck as well.