Hell On Wheels: Liability For Injuries From Falling From Tractors And Being Hit By Trailing Rotary Field Mowers

By John Gehlhausen


Agriculture ranks first in the United States in work injury death rate. The most frequent source of tractor accidents occurring on the farm is overturns. The second most frequent cause of tractor injuries are where the victim is run over by the tractor, in over half of which the victim first fell from the tractor. It is estimated that falls from tractors cause 130 deaths each year. This article deals with the liability of tractor and of trailing rotary field mower manufacturers for operator deaths and injuries. Most cases where liability exists involve either one or both of these manufacturers as such deaths and injuries are 100 percent foreseeable. In many of these cases, the deaths and serious injuries resulting from these falls are preventable. In other cases the seriousness of the injuries can be minimized by one or more technologically and economically feasible safety devices.

Operator Presence Sensing System (OPSS) - Deadman Switches (DMS)

A deadman switch, also known as an operator presence sensing system, is a device that operates to either set an alarm or turn off one or more power sources and/or brake the tractor when the operator leaves the seat with the engine on and the tractor in gear. Depending on the particular manufacturer’s design, numerous variations of this system exist.

The need for these devices, albeit on other types of machinery, was first recognized early in this century. By 1934 the first patent appeared for an OPSS on a tractor. The patentor, Brislin, recognized that one of the needs for the patent was that “it frequently happens that 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.” Perhaps the most famous OPSS patent was that issued to Dooley in 1941 for a “tractor safety control.” This patent became the basis of the famous “Dooley” switch that was activated when the operator’s weight left the seat to stop the engine. Subsequent patents for OPSS on tractors were by Hoffman in 1951 and by Acton in 1954. These patents further illustrated the foreseeability of falls from tractors and injury either by being run over by the tractor or a trailing implement.

In 1967 and 1972 the American Society of Agricultural Engineers in its standards recognized that tractors roll over in normal usage. Logically then, if tractors roll over in normal usage, they also tip in normal usage since a tip is simply an incomplete roll. Tips inevitably lead to tractor operator falls when the tractor is not equipped with seat belts or seat belts are not being used.

While no governmental agency keeps statistics of deaths or serious injuries caused by operator falls from tractors, statistics do exist that put manufacturers on notice that such accidents occur with frequency. Numerous articles, including statistical studies, beginning in the 1960s but covering periods into the 1940s exist showing deaths or serious injuries occurring as a result of falls from tractors. While these articles are not specific to tractor operator falls and include falls of passengers, they are sufficient to put manufacturers on notice that persons fall from various positions on the tractor, including the operator’s seat. Beginning in the 1950s additional articles also put the industry on notice of the fact that persons falling from tractors were being hit by trailing implements. Occasionally one of the major tractor manufacturers will patently recognize such accidents occurring as did Ford in a publication entitled “Safety Tips: A guide to safe tractor and equipment operation” published in July of 1983. The problem has also been recognized in American Society of Agricultural Engineers (ASAE) publications as well as solutions suggested.

Because there is no national reporting system for tractor accidents, it is difficult to get an exact grasp on how many of these injuries have in fact occurred. However, because more and more newspapers are being included in the data bases of various computer services, those services can be used to obtain statistical information as to the current frequency of injuries to tractor operators. For example, a computer search done in mid-1994 covering only a limited number of newspapers for information regarding injuries to tractor users falling from tractors which covered a period beginning in 1984 revealed 36 such accidents involving persons falling from tractors and being hit by trailing mowers, nine additional accidents involving operators falling from tractors and being hit by other equipment, and 27 accidents involving operators falling from the tractors and then being run over by the tractor.

Tractor operators fall from tractors generally because most tractors in this country still are without seat belts. This is not surprising due to the fact that up until 1985 the voluntary minimum standards of the ASAE did not even require rollover protective systems including seat belts to be installed on tractors as standard equipment. Even today a close examination of advertising brochures of tractor manufacturers sometimes can reveal that the operator pictured is not using his or her seat belt. In 1986 the National Safety Council recognized by implication that less than one-third of the tractors in the country were equipped with seat belts by virtue of their recognition that less than one-third of tractors at the time had ROPS. No tractor manufacturer selling tractors in the U.S. has ever placed seat belts on the tractor without also incorporating a rollbar as well.

Even if the tractor involved in the accident were equipped with a seat belt, that operators might not use them has been recognized by tractor manufacturers and mower manufacturers in operator manuals which show or make allowances for tractor operators to function while standing up, intercompany memoranda and by implication from the warnings that appear on tractors equipped with rollover protective systems (ROPS) warning the operator to use the seat belt. Obviously if tractor manufacturers had any expectation of all operators using seat belts, such warnings would not be necessary. In addition, the farm implement manufacturers cannot be ignorant of the fact that years of warning messages to the public to use seat belts in cars resulted in only a minimal usage before the enactment of mandatory seat belt statutes.

The fact that tractor manufacturers have put seat belts on their tractors as standard equipment since 1985 is not an excuse for not also placing OPSS on their tractors. This is because an OPSS, which is a passive safety device in comparison with the active device of a seat belt, is more effective than trying to change behavior patterns of every person operating a tractor who, because of inconvenience, may not use a seat belt. Municipalities do not warn the public to boil their water every time they take a drink. Instead, they purify the water before it is delivered to the public. The same analogy can be used with regard to OPSS. In addition, a tractor in gear without an operator in the seat has no useful function whatsoever. It presents an inherent danger to anyone or property in the vicinity as much as an unguided missile. For a mower used in roadside mowing operations, the danger caused by such a loose tractor can be particularly dangerous to oncoming vehicles due to the possibility of head-on collisions.

Tractor Manufacturer Defenses

Tractor manufacturer defenses in operator fall off cases range from totally false, to mythological, to sometimes meritorious. The false defenses are claims that with an OPSS the tractor could not be used as a stationary power source, claims that the operator would not be able to move around in the seat without tripping the switch, claims of increased electrical reliability problems on the tractor, and claims that the switch would unreasonably increase the cost of the tractor. These defenses have long been rendered totally specious by the actual usage of OPSS which are designed to eliminate such problems on tractors and other machinery already in the field.

If plaintiff’s counsel exposes these claims for what they are, industry then falls back on its “mythological injuries” arguments. It claims that if an OPSS is placed on a tractor larger than a lawn and garden tractor, it will create a false sense of security by allowing the operator to use the system as a shut-off while ignoring other controls designed to terminate power, it will cause injuries because the OPSS could cause a loss of power steering and hydraulic controls, and, finally, it could cause injuries because the tractor could stop too fast if the switch is inadvertently tripped inadvertently. Despite these claims, however, I have yet to see one neutral source ever documenting an injury caused as a result of these suggested possible accident causes. The jury should be advised to balance these mythological injuries against the actual injuries that are occurring every year as a result of the failure to install OPSS.

The one defense that in some cases will have merit is that the injury occurred too fast for the tractor or power source to the trailing implement to come to a stop before injury occurred. This issue should be examined in great depth before filing a case for failure to install an OPSS against a tractor manufacturer. In particular, the details of the fall need to be examined closely. Very often an operator, in falling from a tractor, will grab and hang onto the steering wheel before his or her grip loosens. Even if the operator is killed in the accident, a bent steering wheel can be evidence of a substantial delay of the operator falling to the ground after leaving the tractor seat. In addition, some manufacturers also can be faulted for failing to have handholds installed on the fenders which may have prevented the operator from falling completely from the tractor.

Perhaps most destructive of all OPSS defenses is the simple fact that OPSS were first mounted on lawn and garden tractors in the 60’s. At least one expert has estimated that as of 1995 there are over six million lawn and garden tractors on the market with seat activated OPSS. OPSS have also been and currently are used on numerous other pieces of riding machinery such as combines, cotton pickers, roadside mowing tractor/mower combinations, and skid loaders. Such wide usage would not exist if the problems with OPSS on tractors suggested by manufacturers were a substantial impediment to their usage. In addition, the John Deere “55” and “70” series of tractors that range from 18.5 horsepower to 38.5 horsepower have an OPSS which stops the PTO when the operator leaves the seat.

Rotary Field Mower Accidents

The seriousness or number of tractor operators being run over by rotary field mowers is not new. In 1984 L.R. Piercy authored a paper for presentation at the 1984 Winter Meeting of the American Society of Agricultural Engineers entitled “Fatal Accidents on Kentucky Farms.” He specifically reported:

Machinery accounted for a total of 65 accidents or nearly 6 fatalities per year. [from 1972-1981] A wide variety of equipment was involved, but the most frequent was the rotary field mower which accounted for 19 of the fatalities. The manner of injury reported in nearly all of the mower accidents was contact with the rotating blade or runover with the victims, including both adults and children who were riding on tractors with parents.

The patent history with regard to frontal intake guards for rotary mowers is not nearly as extensive as that for OPSS. Nevertheless, patents do exist since the 1950s that indicate both the need for such a guard and its technological feasibility. In addition, certain manufacturers have placed mowers in the field that either have had or presently have frontal intake guards that do either roadside mowing or heavy duty field mowing. For example, in 1958 an advertisement in the Sears, Roebuck & Company Farm Equipment, Fencing, Garden and Suburban Catalog exhibited a comb guard over a portion of the frontal intake of a rotary field mower. Of particular interest are the tractor/mower combinations built by Kut Kwick Corporation of Brunswick, Georgia which manufactures mowers specifically for highway mowing. The Kut Kwick literature notes that these mowers are built so they can cut down any tree they can bend over, including trees up to 2 1/2" in diameter. These mowers have full frontal metal intake guards that extend down from the mower deck to between 2" and 3" of the bottom of the mower skids. John Deere also markets rotary field mowers that have frontal intake flying object guards that are of solid metal.

Most evidence in these cases, however, revolves around the feasibility of what the industry unaffectionately calls the “Sevart guard.” The “Sevart guard” came about in 1978 as a result of consulting engineer John Sevart of Wichita, Kansas designing a comb-type frontal intake guard for a rotary field mower at the request of Wausau Insurance Company. In 1982 Mr. Sevart and Bradley Klausmeyer published an ASAE paper entitled “Design and Development of Intake Guards for Agricultural Rotary Mowers.” (Pl. Ex. 46) The guard has been the focal point of litigation against rotary field mower manufacturers ever since. As of this date no mower manufacturer has adopted the Sevart design for installation on any of its rotary field mowers. Logic leads to the conclusion that the reason they have not is because it would be a tacit admission that such a guard could and should have been on their mowers at least since 1982, if not before.

Because of industry attacks on the “Sevart guard” as to its practicality, it becomes incumbent on the plaintiff to prove that the “Sevart guard” will not materially impair the mowing function of the machine to the point that use of the guard is not practical. It is also essential to prove that the guard is effective in substantially reducing injuries in terms of either numbers or severity in comparison with the normally unguarded mower frontal intake. This is accomplished by use of video taped tests done with a “Sevart guard” constructed for the mower involved in the accident.

The mower manufacturers contend that the guard suffers from essentially two defects that make it impractical to use in mowing. First, they argue the guard causes the mower to dig into the ground on uneven terrain and, second, they claim it clogs with vegetation making quality mowing impractical. Both of these industry contentions are without merit. With regard to the contention that the guard causes the mower to dig in when it catches on bumps on the ground, the answer is to place the guard so that it is approximately 1" below the level of the mower blade. The height of the mower cut can then be raised 1" and the mower is in exactly the same position it would have been if the blade was digging into the ground instead of the frontal intake guard. Obviously it is much safer to have a frontal intake guard make contact with dirt, rocks and other obstructions than a rapidly turning blade that can create a danger of flying objects.

The contention with regard to the guard clogging can be refuted by a multi-camera video shot with one camera attached to the tractor looking directly down at the mower intake, a second camera in front of the tractor showing the height and thickness of the vegetation, a third camera aimed off the back of the tractor showing the quality of the cut, and a fourth camera mounted on a vehicle driving along side the tractor showing a side view of the tractor and mower in actual operation. These four videos then can be synchronized by the videographer so that they can be shown on a quadruple screen video that allows the jury to look at all aspects of the cut as it occurs. The video will demonstrate that the guard, while it does have a tendency to act as a rake, is self-cleaning as a result of the natural forward movement of the mower over the ground.

While mower manufacturers will still maintain that even the slightest amount of vegetation collecting in front of the mower guard as it passes above the ground will impair the quality of the cut, their arguments are without merit in comparison with what the several tons of weight on the tractor tires does to the vegetation just before it passes beneath the mower.

Arguments that the frontal intake guard bends down the vegetation and thus makes it difficult to cut are also completely meritless as the guard in this sense is no different from the lip of the mower deck that has exactly the same effect.

Showing that the guard will be effective in substantially reducing the likelihood or extent of harm in comparison with an unguarded mower creates a different set of problems. The usual way this is done is by an anthropomorphic dummy which is first run over by the tractor and then encounters the mower with the frontal intake guard. The effectiveness of the guard in keeping any portion of the dummy from passing beneath the mower depends on the distance between the guard and the ground at the time the mower reaches the dummy. This distance can vary depending on deviations in the levelness of the ground as the mower travels.

However, just because a portion of a dummy passes beneath the mower, it does not necessarily mean injury from the blade will occur. Assuming that the guard is set by the operator approximately 1" below the level of the blade, even if the cutting is at such a height that the guard will not keep out a body, the chances of injury are greatly reduced due to the fact that the body most likely will remain below the level of the blade as the blade passes above. A more likely scenario, however, is that the guard will push the dummy for a substantial distance before encountering a dip in the level of the ground that could allow a portion of an arm or a leg to slide beneath the guard. Even when this happens it must be kept in mind that the leg or arm will generally be pinned to the ground by the guard itself, thus making contact with the blade difficult, if not impossible. In any event, even if a portion of a limb could make contact with the blade, it cannot be doubted that the injuries would be less severe than if no frontal intake guard at all were on the front of the mower. It also must be kept in mind that if the tractor powering the mower were equipped with an OPSS, the tractor or mower power would be brought to a speedy halt once the operator fell from the seat. Thus pushing of a body in front of the guard for a substantial distance would not occur.

Mower manufacturers, although they try, cannot legitimately contend that the guard needs to be 100 percent effective in order to be mounted on the machine. Edward J. McCanse, the former Director of Product Safety of Woods Division of Hesston Corporation, the manufacturer of over two hundred different models of field mowers, has testified that the flying object guards which are sold by mower manufacturers as optional equipment are only 10 percent to 40 percent effective. The “Sevart guard” can also be analogized to seat belts, air bags, padded dashes and safety glass in automobiles, none of which are 100 percent effective in preventing injury. Nevertheless they are included on motor vehicles due to the increased likelihood they have of reducing either an operator’s chances of or extent of serious harm in the event of an accident.

Finally, cost of the “Sevart guard” should not be an impediment to guard installation. In 1994 a “Sevart guard” for a 5' mower would cost less than $100 to manufacture. This compares with the $275 cost of the 10 percent to 40 percent effective optional chain guard sold by manufacturers to prevent injury from flying objects.


Before they are accepted, cases involving operators falling from tractors and being run over by rotary intake mowers should be carefully evaluated as to the liability of each defendant. They are complex and present different sets of problems. Once a case is determined to exist, extensive discovery and preparation are absolutely necessary in order to be able to pursue the case to a successful conclusion. Costs in such cases can run between $50,000 and $200,000 if trial is completed. Meritorious cases should be pursued. If they are not, unnecessary deaths and injuries from these accidents will continue to occur until the tractor and mower manufacturing industries understand that it is more expensive to pay verdicts than to continue to ignore proven safety devices.

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