The Tennessee Highway Patrol says two tractor-trailers were traveling southbound on I-81 in Hamblen County yesterday when one struck the other in the rear. The impact caused them to catch fire and destroyed both tractor-trailers. One driver was airlifted to Johnson City Medical Center and the other was taken by ambulance to Morristown Hamblen Medical Center. Both drivers were wearing their seatbelts. The southbound lanes were both closed for several hours as a result of the crash. The names of those involved will be released at a later time.