Abstract: At 4:16 p.m. on October 23, 2015, a truck driver and three workers were offloading two Tigercat grapple skidders (model number: 620D) from a 2009 Kenworth semi-truck and 1998 Talbert detachable gooseneck lowboy trailer at a worksite. After offloading the skidders, the truck driver began the process of hooking the trailer back to the truck, which was parked on an incline with 22 percent grade (12.4 degree slope). The sloped road where the truck and trailer were parked led directly downhill to a two-lane highway. As the truck driver stood in between the truck and trailer operating the controls/leavers to lift the trailer, the truck and trailer began to roll. The truck driver was run over by the truck's 32-inch wheels and was killed as a result of suffering multiple injuries that included a fractured spine, and lacerations of the brain stem and aorta. The other three workers escaped from the incident unharmed. The incident investigation revealed that the neither the trailer nor the truck were chocked and brakes on both were not set.