A Sebring motorcyclist was killed in a Highlands County crash on Saturday after he slammed into the back of another vehicle, authorities said.According to a Florida Highway Patrol (FHP) report, the 20-year-old motorcyclist was traveling northbound on U.S. Highway 27 at a high rate of speed in the center lane, north of South George Boulevard at about 9:06 p.m.Ahead of the motorcycle, and also in the center lane, was a sedan-type vehicle driven by a 27-year-old woman from Lake Placid.When the motorcyclist attempted to switch into the outside lane, the sedan did the same maneuver, the report stated.The motorcycle then slammed into the back of the sedan.The Sebring resident suffered serious injuries from the crash and was taken to an area hospital where he was pronounced dead.The crash remains under investigation.