Moats, who was wearing a seat belt, was pronounced dead at the scene by Conner. An autopsy will be performed this morning at Lehigh Valley Medical Center in Allentown, Pa., Franklin County Coroner Jeffrey R. Conner said.
McDonald was flown to Washington County Hospital in Hagerstown, police said. A hospital spokeswoman said she later was discharged from the emergency room.
Two passengers in McDonald's vehicle, Ralph Eugene Doyle, address unavailable, and a 2-year-old girl in a child safety seat, were uninjured, police said.
Moats was a 2008 graduate of James Buchanan High School in Mercersburg, Pa., and was employed as a welder by Johnson Controls Frick in Waynesboro, Pa., according to his obituary.
He is survived by his parents, Donald E. Moats and Triniti L. Peck Rosenberry, his stepmother, Anna M. Barto Moats, one daughter, Bailee R. Thomas; one brother, Andrew L. Moats; his fiancÃ©e, Samantha R. Thomas; and other relatives, according to his obituary.
In the Friday afternoon accident, Everly was southbound on I-81 in a 1993 GMC Sierra about 3:30 p.m. when the vehicle crashed into the rear of a 2002 Freightliner tractor-trailer that was parked off the west side of the southbound lanes, police said.
The driver of the tractor-trailer, Bonny L. Lewis, 65, of Mount Vernon, N.Y., suffered minor injuries in the crash, police said.
Whiteout conditions were reported at the crash site at the time the accident was reported, Conner said.
The southbound lanes of I-81 were closed after the crash, with traffic being detoured onto Pa. 696 south to Exit 20 in Scotland, Pa., resulting in traffic backing up several miles.
--Â Don Aines