Abstract: Highway 264E was being expanded to four lanes. Employee #1 was the supervisor of the job and had instructed the driver of a dump truck to back up to receive a load of undercut. Because of another truck on the right side, the driver of the dump truck delayed backing up approximately 15 to 30 seconds until the truck on the right was clear. The driver checked both mirrors, saw no conflict, and proceeded to back up. After backing approximately 45 to 50 ft into position, the driver stopped to receive the undercut. Coworkers ran toward his truck, and the driver looked down and saw that he had run over and killed Employee #1. The back-up alarm was functional and audible above the surrounding noise.