LEXINGTON COUNTY, SC — The driver of the car that killed a state Department of Transportation worker on Interstate 20 in Lexington County Monday afternoon has been charged with driving under the influence and leaving the scene of an accident, according to the state Highway Patrol.

Thomas Lee Stafford, 39, is accused of driving drunk when his 2003 Nissan SUV hit Nicholas Johnson and fatally wounded Nicholas Johnson, who was walking along the road’s emergency lane near mile marker 62, according to Highway Patrol spokesman Brent Kelly.

Stafford continued to drive for another half-mile or so after hitting Johnson, Kelly said, before eventually pulling off the road. Stafford is charged with driving under the influence involving death, a felony, and leaving the scene of an accident. Stafford’s vehicle swerved to the right and hit Johnson from behind, killing the man, but Highway Patrol investigators aren’t sure as to why.

Johnson, 21, was pronounce dead at the scene.