Abstract: Employee #1 was driving a four-wheel drive, articulating Caterpillar dump truck (Model Number D25D) without a load down a hill with a slope of 13 degrees. Employee #1 drove up onto a dirt/gravel type of 14 inch high waterway swell across the road and then lost control of the dump truck. He drove off the right side of the road into the gutter, then scraped the right side of a dirt embankment and struck and grazed a pine tree. The truck's articulating cab section then flipped onto the road, landed on its left side, pinning the driver under the cab's frame section. The front left side of the cab's metal roof frame pinned Employee #1's head to the ground. During the investigation, the driver's seat belt was in its unused retracted position and gear shifter was in third gear with the 4 by 4 selector in the "in mode" . The truck's brakes and steering operations were tested and found to have no mechanical problems after the accident.