Thomas J. Cocchiola, PE ::::
Case Synopsis: Tractor trailer driver routinely transported loads of mulch in an open top trailer. On the day of the accident, the driver arrived at a facility and waited while the trailer was loaded. He then proceeded to cover the trailer with a tarp before leaving the facility. The trailer was equipped with a ladder on the front bulkhead and a set of steps on the tailgate enabling workers to climb up and tarp the trailer. The driver climbed the front ladder, pulled the tarp over the top of the trailer, and then walked around to the tailgate to secure the tarp. The driver climbed the tailgate steps and stood on one tread while he pulled the tarp and attempted to secure it. At one point, his right foot slid across the tread surface and slipped off the end of the step. The driver lost his balance and was injured as he fell to the ground.
Engineering Analysis: Engineering analysis was conducted to determine whether the trailer tailgate access system was adequately designed based on fundamental engineering principles and practices for mobile equipment. The analysis determined that the width, depth, and shape of the step treads were inconsistent with generally accepted design parameters. The treads were too narrow, toe clearance was inadequate, and there were no end restraints. Step tread deficiencies caused the driver’s foot to slip off the tread while he was tarping the trailer. The tailgate access system also lacked rails or handholds enabling drivers to maintain their grip while climbing and tarping loads. Consequently, the driver was unable to hold on when his foot slipped off the tread.
Conclusion: Trailer access system design did not permit drivers to safely maintain three-point contact in accordance with fundamental engineering principles.Case Studies