This diversity action arose out of a collision which took place on Interstate Highway 65 (I-65) a short distance north of Bowling Green, Kentucky. The plaintiff is the personal representative of three occupants of a south-bound Ford Pinto who received fatal injuries in the collision. The other vehicle was a 1966 Plymouth owned by the defendant James A. Seymour and his wife Elphreda B. Seymour who was driving the automobile north on I-65 at the time of the collision. The Seymour automobile was pulling a U-Haul trailer which Mr. Seymour had rented from an agent of the defendant Amerco Marketing Company of Memphis, Inc. (Amerco) in Memphis, Tennessee the previous evening. Amerco also furnished a trailer hitch which was attached to the rear bumper of the Seymour automobile. The complaint alleged that Amerco was "negligent in hooking said trailer and hitch to said automobile, so that, the attachment was defective and unsafe. Consequently. ... the connection fell apart, causing the automobile to go out of control and into a violent collision with another vehicle operated by Junior J. Myers." The complaint also alleged that Mr. and Mrs. Seymour were careless in the operation of their automobile and trailer and that this was a contributing cause of the collision.