Abstract: Employee #1 and his immediate supervisor were moving an oil and gas seismic support vehicle along ranch roads to a public highway, Employee #1 was driving the vehicle. As the vehicle came down a long moderately steep hill, it suddenly sped up, gaining speed as it went down the hill. At the bottom of the hill it left the roadway and went into a dry creek bed, Employee #1 was ejected through the front opening of the vehicle. Employee #1's head struck the overhead canopy frame, and then the middle of the muffler; blood and hair were observed along the right side of the engine cowling and engine. Employee #1 came to rest with his head against the right side of the front bumper; his body was parallel to the bumper with his body projecting away from the bumper. The most probable cause of the accident was excessive speed. The operator was unable to stop the vehicle safely at the speed the vehicle was traveling. There also was no seat belt to prevent the operator from being expelled from the vehicle. Employee #1 was killed.