Abstract: Employee #1 was driving a tractor equipped with a rotary mower. He was mowing west just off the right shoulder of the eastbound lanes of a highway. When he reached an overpass, he turned right, driving onto the pavement of the right eastbound lane. Although the highway was closed to the public, construction traffic was moving in the area and Employee #1 was struck by an empty 10-wheel dump truck, which was being operated by a private contractor. The collision tore the engine and front wheels off the tractor, leaving the driver's section and roll-over device intact. Employee #1, who was not using a seat belt, was thrown in the direction of the impact. He was run over and/or dragged by the motion of the two vehicles after impact and killed. Safety back-up trucks were available but Employee #1 had said that he would not need backup protection because he would not be on the highway pavement.