From State Police: ROCKBRIDGE CO., Va. – Trooper D. B. Taylor is investigating a single vehicle crash which resulted in two fatalities.  The crash occurred on Interstate 81, just south of Exit 180 at 6:51 a.m. this morning (Feb 15) in Rockbridge County. A 2004 Kenworth tractor trailer was traveling south on Interstate 81 in the left lane, when the vehicle ran off the left side of the roadway, striking the trees in the median and overturned. The 2004 Kenworth was driven by Mark Tracy Lucas, 42, of Stanley, VA.  Mr. Lucas was not wearing a seatbelt and died at the scene. The passenger in the vehicle, Gerald Allan Hilliard, 68, also of Stanley, VA, was not wearing a seatbelt and died at the scene. The Virginia State Police Crash Reconstruction Team and Motor Carrier Unit were called to assist with the crash. The crash remains under investigation.