Dead-Man Switches: The Next Step in Farm Tractor Safety
Agriculture ranks fourth among all U.S. industries for work-related fatalities. We have previously reported that tractor rollovers are the most frequent cause of injury and death on farms. The second most frequent cause, however, is upright tractors running over farm workers. In over half of these cases, the victim fell off of the moving tractor and was then run over by the tractor. These injuries and deaths are often preventable.
Many safety engineers now recommend that farm tractors be equipped with dead-man switches, also known as operator presence sensing systems (OPSS). These safety devices set off an alarm or turn off one or more power sources and brake the tractor when the operator leaves the seat with the engine on and the tractor in gear.
The need for a dead-man switch on farm tractors was recognized early in this century. The first patent for a dead-man switch on tractors observed that frequently “the driver slides or tumbles from his seat to the ground and is out of reach of the usual ignition switch. If the implement being towed is a wide gang of plows, disks, or harrows, the fallen driver may be in danger of life or limb from the oncoming, uncontrolled implement.”
The feasibility as well as desirability of a dead-man switch on farm tractors can no longer be seriously questioned. Dead-man switches were first mounted on lawn and garden tractors in the 1960s. Today there are more than 6 million lawn and garden tractors on the market with these safety devices. Dead-man switches have also been, and currently are, used on many other pieces of riding machinery, such as combines, cotton pickers, roadside mowing tractor-mower combinations, and skid loaders.
The John Deere 55 and 70 tractor series are now equipped with a dead-man switch that stops the power take-off shaft when the operator leaves the seat. Farm tractor manufacturers who refuse to adopt reasonable safety measures may soon find themselves liable under our product safety laws for preventable injuries and fatalities.