Johnny Lynn Etheridge of Sparta, 45, was driving east on Sparta Highway in this 1997 Ford truck with a lawn mower trailer when he left the highway for unknown reasons, traveled down an embankment, and collided with several trees.The accident occured just after 11 p.m.Etheridge was removed from the truck by DeKalb EMS and taken to a landing zone near the scene of the accident, where he was airlifted to Vanderbilt University Medical Center.