Using steps and rails can reduce the impact forces to a trucker’s body by 75% to 80%, the research found. When drivers exit a conventional tractor without grab rails and steps, the force of impact averages more than seven times their body weight and reaches as high as 10 times body weight. If they use rails and steps, the forces are less than two times body weight on average. Numbers were similar for cabover tractors and trailers.
In the study, 10 male drivers performed more than 400 exits from the cabs and backs of five commonly used commercial vehicles, including cabover and conventional tractors, a cube van and a box trailer. Drivers exited the vehicles under various conditions, both with and without using grab rails and steps, while researchers measured foot-to-surface impacts.