A worker was operating a bulldozer at the top edge of a sloped excavation. The trench was being developed for a drainage ditch six feet (1.8 meters) deep. The surface was covered with snow and ice, and the bulldozer slid out of control down the side of the excavation. It tipped on its side and pinned the operator under the rollbars. He was not wearing the required seatbelt, which would have held him inside the operator's cage and saved his life. Had the edge or the rim of the excavation been clearly marked with colored flag tape or another kind […]