Abstract: On July 14, 2010, an employee was towing a 12-ft wide by 64-ft long mobile office unit with a Frontline tractor trailer. The mobile office unit trailer got a flat tire. This was the third flat tire that they had since beginning this trip earlier in the day. The employee parked the tractor trailer and mobile office unit partially on a two-lane road, and partially on the grassy shoulder. The grassy shoulder was sloped from 11.1 to 17 degrees along the parked unit. The grassy shoulder also had voids and holes, and did not present a stable or level surface. The employee was partially underneath the trailer using three 12-ton Low Profile hydraulic bottle jacks, some wood and cement blocks to raise it so that the tire could be replaced. As the employee started jacking up the trailer, another tractor trailer drove past the parked vehicles. After the tractor trailer passed, the trailer unit fell over and onto the employee. He died at the scene. The cause of death was mechanical asphyxia and a crush injury of chest, abdomen and pelvis. Injuries included fractures and lacerations.