Authorities are investigating a fatal accident involving a tractor-trailer and a motor home along Interstate 24 in Clarksville Thursday night.The incident occurred around 3 p.m. on I-24 west near mile marker 1. According to the Tennessee Highway Patrol, a motor-home with Illinois plates was disabled and parked on the right shoulder of the roadway when the accident occurred. Authorities reported a tractor-trailer failed to slow for traffic and swerved to the right, causing the truck to jackknife and strike the rear of the motor home. Sixty-five-year old Roger LaGrone, who was working underneath the RV at the time of the accident, was killed. A 67-year-old passenger in the RV also sustained injuries in the accident. The driver of the tractor-trailer, 26-year-old Carl Anderson, was not injured.