Abstract: At about 10:00 a.m. on July 11, 2006, Employee #1, of Loyer Enterprise Transportation, was setting shimming bars on the goose neck attachment of a lowboy trailer during the loading of a large dump truck on the trailer. The truck was a CAT D400E rock dump truck model and was going to be returned to a rental equipment yard. A coworker positioned the truck onto the trailer with the front tires elevated on the rear platform over the three road wheels of the lowboy, shifted the truck to a neutral position, engaged the footbrake, set the hydraulic parking brake, and left the engine idle prior to the incident. The driver did not block the rear wheels of the dump truck prior to returning to the gooseneck attachment. During the leveling of the lowboy trailer with the tractor trailer using the hydraulic goose neck attachment, the dump truck rolled off its elevated position. The dump truck moved backward and crushed Employee #1 between the goose neck and the truck's rear suspension. The coworker ran to the opposite side of the lowboy, called for help from nearby coworkers, and moved the dump truck back to its original position as other coworkers blocked the rear wheel tires. An emergency service unit arrived on site, and transported Employee #1 to a nearby hospital, where he died upon his arrival. After the employee's death, the braking system of the dump truck went through an extensive evaluation and testing upon its return to the rental equipment yard. Two enforcement officers and the equipment maintenance personal tested all aspects of drive train, gear settings, floor brake system, and parking brake system. Hydraulic oil samples were extracted and analyzed. No discrepancies were found during this investigation to suggest any failure of the braking system of the dump truck.