WALTERBORO ­— A woman who died in a single-vehicle accident Tuesday on Interstate 95 had been en route to a memorial service for her husband who died earlier this month.

Lynell Searcy Stapleton, 76, of St. Simons Island, Ga., died at the scene of the 8 a.m. accident near mile marker 55 in the Walterboro area, Colleton County Coroner Richard Carter said. He said Stapleton was at the wheel of a northbound 2004 Chevrolet SUV when the vehicle inexplicably hit a guard rail head-on, traveled down an embankment and overturned.

Carter said three passengers —the driver’s daughter and two grandchildren — were slightly injured and were treated at a hospital. The cause of the accident is unknown. The S.C. Highway Patrol is investigating. The accident blocked one lane of traffic for 2 1/2 hours.

Stapleton was the wife of retired Army Col. George J. Stapleton, who died at age 78 on Nov. 8 at St. Simons Island.