A 34-year-old male welder was killed after being runover by an unmanned pipelayer. The victim worked for a pipelaying construction company as a welder. On the day of the incident the victim, a welder's helper, and an equipment operator drove to the work site together to begin the day's activities. Access for the worksite was via a single lane temporary road winding up the mountainside through a mixed hardwood forest. The ½ mile dirt road carved its way up the hillside; on the left was the bank, on the right was a steep drop off. As the victim drove his pickup truck up the steep mountain path, the weight of the welding equipment in the truck bed caused the front wheels to lift off the ground and the driver lost control of the vehicle. It rolled off the hillside and overturned three times, landing on its side, resting against some trees. The three escaped uninjured and climbed to the road. To retrieve the truck, a pipelayer which was parked further up the mountain on a semi-flat area, was driven partway down the hill. The cable from the sidearm of the pipelayer was attached to the hitch on the rear of the pickup and the truck was uprighted and dragged to the dirt road. While the cable was attached to the pickup truck, the bulldozer began to roll forward, unmanned, down the hill. The welder's helper and the operator were able to get out of the way of the path of the moving equipment. However, the victim in this incident was crushed as the pipelayer ran over him. In order to prevent similar occurrences the FACE investigators recommend: 1. operators should be aware of limitations of the equipment.