A single-car accident closed the inner portion of Interstate 440 near the Western Boulevard interchange Friday morning.
At one point, backups extended to the U.S. 1-U.S. 64 split in Cary.
The accident happened about 5 a.m. Police said the driver, Vernon Davis, 27, was critically injured and taken to WakeMed Raleigh campus.
Officers closed the highway while they investigated, said police spokesman Jim Sughrue.
"They worked as quickly as they could, but they have only one chance to gather the information and evidence at the scene," he said.
An officer estimated Davis was driving his 2002 Chevy Suburban 86 mph when he left the road to the right, overcorrected and lost control. He was not wearing a seat belt and was ejected from the vehicle as it rolled several times, a wreck report said. A search warrant indicated that Davis is suspected of driving while impaired.