Abstract: At approximately 8:10 a.m. on January 17, 2000, Employee #1 was assigned to work with the post-driver truck installing 3-ft-high galvanized iron guardrails. Employee #1 was kneeling below the left door while checking the drive shaft when a flatbed truck backed into him hitting his lower left back. Employee #1 was being knocked down by the truck's rear metal bumper and his coworkers signaled the truck driver to stop. Employee #1 was wearing ear plugs and did not hear the truck's back-up alarm due to the high ambient noise. The truck driver did not see Employee #1. Employee #1 sustained a fractured vertebra in his lower back and was hospitalized.