Abstract: At 3:00 p.m. on October 28, 2020, Employee #1, employed by an underground construction company, was working alone to connect a 2013 CAM Superline flatbed trailer to a 2007 9200i International tractor truck. The equipment was in a staging area on a private lot and was needed at a worksite one mile away. The driveway of the staging area sloped downward to a public road, and the truck faced this downward slope. The connection between the truck and trailer consisted of a pintle hitch on the truck and a lunette ring on the trailer, as well as air lines for service and emergency/parking brakes, an electric cable for lights, and chains to secure the pintle coupling. After backing up the truck to the trailer to make the pintle connection, the employee set the truck's parking brake and exited the truck's cab to raise the trailer's jacks and connect the air lines, electric cable, and chains. After connecting the trailer to the truck, the employee got back into the truck and attempted to drive the truck out from the staging area. However, the trailer brakes would not release. The employee exited the truck cab to investigate. The truck's engine was running and in neutral, but the truck's parking brake was not set, and the truck's wheels were not chocked. Employee #1 took action to release the trailer brakes, whereupon the truck and trailer combination began to roll forward down the driveway. The employee ran alongside the truck and tried to get into the truck's cab to control/stop the runaway truck and trailer. The truck and trailer rolled from the private lot staging area, across the public roadway, and down into a field where a wood utility pole with guy wire stood. The employee was caught between the driver side cab and the utility pole. Employee #1 sustained multiple traumatic injuries to the chest and midsection and was killed.