Preventing Death and Injury in Tractor Overturns with Roll-Over Protective Structures
Tractor overturns are the leading cause of occupational agricultural deaths in the United States. Between 1992 and 2005, 1,412 workers on farms died from tractor overturns. The Roll-Over Protective Structure (ROPS) was developed to protect tractor operators from death and disability from these events by providing a protective zone for the operator in during a tractor overturn. ROPS are most effective when used in conjunction with a seatbelt, which keeps the tractor operator inside the protective zone during an overturn. The effectiveness of ROPS has been well documented (Thelin, 1998). The National Institute for Occupational Safety and Health (NIOSH) has estimated that fatality rates due to tractor overturns could be reduced by a minimum of 71% if all tractors in the U.S. were equipped with ROPS.
In a recent issue of the Journal of Safety Research (vol. 39, issue 5, 2008), a NIOSH-authored article, "Tracking the Prevalence of Rollover Protective Structures on U.S. Farm Tractors: 1993, 2001, and 2004," summarized the changes in the prevalence of ROPS use over an eleven year period. The data, which were collected for NIOSH by the U.S. Department of Agriculture (USDA), National Agricultural Statistics Service (NASS), show ROPS use has increased from 38% in 1993 to 51% in 2004 (an average increase of 1.2% per year). More recent NIOSH/NASS ROPS surveillance data indicate the prevalence of ROPS-equipped tractors reached 59% in 2006 (NASS, 2008). While the increase in ROPS-equipped tractors is encouraging, the slow rate of ROPS adoption continues to frustrate the agricultural safety community.
The Journal of Safety Research article shows that farms in the South and the West had the highest percentage of ROPS-equipped tractors at 52%, compared with 46% in the Midwest and 40% in the Northeast. Additionally, the older the age of the primary farm operator, the less likely tractors on the farm were equipped with ROPS. On farms with operators younger than 55 years, over 50% of tractors were equipped with ROPS. When the operator was 25- to 34-years old 57% of the tractors had ROPS. The lowest percentage of ROPS-equipped tractors was found on farms operated by farmers over 65 years of age at only 42%. Farms with a value of sales over $99,999 had the highest percentage of ROPS-equipped tractors (67%). The lowest percentage was on farms with a value of sales less than $10,000 (40%).
It may seem obvious that farmers with limited resources do not have the capital to buy new tractors or retrofit their existing tractors, and cost has been identified by farmers as one barrier to retrofitting ROPS on older tractors, even if they will continue to be used for decades. However, economics are not the only factors influencing reluctance to place ROPS on older tractors. Studies have shown that even with an economic incentive, ROPS acceptance by the farm operator was not 100%. In New York, only 12% of farm operators interviewed were willing to pay the $400 for a ROPS retrofit, while 40% said they would never accept a retrofit even if it were free (Kelsey, May, and Jenkins, 1996). A second study found that farm operators in New York were more willing to retrofit as subsidy offers increased, with a cost-sharing incentive of 75% to 90% encouraging the greatest number of farm operators to retrofit. However, even when offered a 100% subsidy, 20% of the interviewed farmers stated they would not retrofit an older tractor with a ROPS (Hallman, 2005). Common reasons given by farm operators for not placing a ROPS on older tractors include:
- the ROPS are too tall to allow tractors to enter farm buildings or interfere with farm operations where low clearances are an issue (e.g., tractors used in orchards);
- the belief, particularly among older farmers, that they know how to control a tractor, making ROPS unnecessary;
- what they perceive as the inconvenience and time needed to purchase a ROPS and have it installed on their tractor.
These and the economic factors make campaigns to encourage equipping older tractors with ROPS difficult.
Although federal regulations and voluntary standards have been set as a means of reducing injury and death from tractor overturns, these measures have limitations. In 1976, the Occupational Safety and Health Administration (OSHA) required all agricultural employers to equip all employee-operated tractors manufactured after October 25, 1976, with ROPS and safety belts. This standard, which is still in effect today, does not apply to family members (family-only farms) and, since its inception, has not been enforced on farms with fewer than 11 full-time employees in 47 of the 50 states. California, Oregon, and Washington are the exception, and cover all farms with hired workers. These restrictions mean that only about 8% of all farms in the U.S. are covered by this standard. Another major effort to increase the use of ROPS was taken by the American Society of Agricultural Engineers (ASAE— now the American Society of Agricultural and Biological Engineers, or ASABE). In 1985, ASAE adopted a voluntary standard, S318.10, which encouraged tractor manufacturers to install ROPS and seatbelts on all new agricultural tractors for use in the U.S. market. All major tractor manufacturers agreed to adopt this standard, and since 1986, nearly all new agricultural tractors sold in the U.S. have been equipped with ROPS and seatbelts as standard equipment.
It was anticipated that the voluntary ROPS standard would lead to a decrease in the number and rate of tractor overturn deaths on U.S. farms. Yet between 1992 and 2005, tractor overturn fatality rates have not decreased significantly because of the large number of older tractors in use on U.S. farms that are not equipped with ROPS. Based on the current rate of ROPS adoption, we would not expect to see fatality rates from tractor overturns in the U.S. to be at or near zero until sometime after the year 2020. The loss of life in the interim is unacceptable. The data suggest that incentive programs addressing the concerns of older farm operators and low-income farm operations may help increase retrofitting of ROPS on older tractors.
NIOSH, through its network of Agricultural Safety and Health Research Centers and the National Occupational Research Agenda (NORA) Agriculture, Forestry, and Fishing Sector Council, is making the retrofitting of ROPS on older tractors a major research and outreach priority. As a part of this process, we would like to hear your success stories or ideas about how to encourage the retrofitting of ROPS on older farm tractors and protect America’s farmers and farm workers.
—John Myers, MSF
Mr. Myers is a Health Statistician in the NIOSH Division of Safety Research.
References
- Hallman E. [2005]. ROPS retrofitting: measuring effectiveness of incentives and uncovering inherent barriers to success. J Agric Saf and Health 11(1):75-84.
- National Agricultural Statistics Service. [2008]. 2006 farm and ranch safety survey. Report No. Sp Cr 3-1 (1-08). Washington, DC: U.S. Department of Agriculture, National Agricultural Statistics Service.
- Kelsey, T. W., J. J. May, and P.L. Jenkins. [1996]. Farmtractors, and the use of seat belts and rollover-protective structures. Am J Ind Med 30:447-451.
- Thelin A. [1998]. Rollover fatalities—Nordic perspectives. J Agric Saf and Health 4(3):157-160.
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Comments
Thank you for this update. My father in law who knew tractors like the back of hand was killed in a tractor rollover in 2000. I wish I had known about this then and perhaps the outcome would have been different.
Reading your reasons for resistance though, I am sure he would score on all accounts. I hope this message may somehow get to the Grandpas out there who if they don't want to do this for themselves, think of the sad little faces that were robbed of years more of hanging around with Gramps, let alone the unabated grief of widow and sons.
Posted 1/5/08 at 1:57 pm
How to get the retrofit? Any funding?
Posted 1/5/08 at 2:38 pm
The best way to identify a ROPS retrofit for your tractor is to contact a local equipment dealer selling the brand of tractor you need a retrofit for. If the tractor is not made anymore, but the brand was taken over by another manufacturer (e.g., New Holland covers Ford, CASE, CASE-IH, and some IH brands; AGCO covers White, Allis Chalmers, Massey Ferguson, and some other older brands), you could contact them to see what ROPS they have available. For the more common tractors made in the 1960s–1980s, a ROPS should be available. If the tractor is older than this, and is not a common make of tractor, locating a ROPS will be more difficult, although there are some companies who make ROPS for certain older tractors. You can locate a possible manufacture at the following website:
If you live in the state of New York or in the state of Virginia, additional help is available for both locating a ROPS and with the reducing the cost of purchasing the ROPS. Information on these two programs can be found at the following websites:
Unfortunately, most other states do not have an incentive program available to help offset the cost of retrofitting a tractor with a ROPS.
Posted 1/6/08 at 10:41 am
Maybe a singular, clear message that speaks to their views "make your own decision to be safe—put on a ROPS"
In 45 min program to about 40 farmers, I shared my own angst that "I do not know how I could live with myself if my teen aged daughter were killed in a rollover I knew how to prevent." Then I left a dramatic pause for them to consider how this applied in their work. Marie had just started driving the tractor for haymaking. Two farmers took action to notify me about how they changed their risk after this decision point. One called the dealer that afternoon to install a ROPS to protect his 17 year old son. The second one decided to sell the tractor for antique tractor displays so his teenaged daughter would be safe. If two felt compelled to contact me, I bet there were others who also took action.
Posted 1/5/08 at 3:44 pm
Has there been research into other passive or active controls to PREVENT rollover, and are those technologies being put to use as old equipment is replaced? Are there any technologies that are safer when a tractor rolls into a bog or pond?
Posted 1/5/08 at 4:03 pm
Currently, the most effective passive engineering control to prevent tractor overturn deaths remains the ROPS and ROPS cab, which is why ROPS are standard equipment on nearly all new tractors sold in the United States. Tractor manufactures have changed the designs of tractors over time providing them with a wider wheel-base and a lower center of gravity, which makes the tractor less prone to overturn, but not overturn-proof.
There has been research done in the past looking at sensors or other instruments that indicate when a tractor is about to overturn. However, these types of sensors have been used more for educational purposes rather than as standard equipment on new tractors. Two major reasons these types of instruments are not placed on tractors are: the sensor only tells the operator that tractor is about to overturn, but cannot tell the operator what corrective action to prevent the overturn; and, in general, there is not sufficient time for the operator to react and prevent the overturn when the sensor indicates an overturn is occurring (most fatal tractor overturns occur in less than 1 second).
There has been a large body of research done on the environmental and physical characteristics that increase the risk of a tractor overturn. These include operating tractors on excessive slopes, improper hitching of towed equipment, hitching tow chains or tow straps too high on the rear of the tractor, and excessive speed when turning a tractor. Information on how tractor operators can reduce their risk of overturning a tractor are available from their local USDA state extension office, or by searching the following agricultural safety database:
As for the hazards caused by ponds, bogs, canals, or other bodies of water, the most effect means is to not use tractors near these areas. If this is unavoidable, the next best option is to have the tractor equipped with a ROPS cab, which should provide the operator additional time to react to having the tractor overturn in to water. I am not aware of any other technologies that are commercially available that deal with this issue.
Posted 1/5/08 at 4:03 pm
I wonder if there was any study made of the center of gravity of all type of tractor in respect to the slope angle of the ground, on which the tractors are operated?
Other option may be to install the simple clinometers on the tractors and indicate the critical angle, which should not go beyond, to assist the operators.
Posted 1/5/08 at 9:00 pm
There has been research done in the past looking at the issue of center of gravity and how that impacts the stability of farm tractors not only when on a slope, but also when lifting heavy loads with a front-end loader, or towing an object with a chain or tow rope. This research led tractor manufacturers to change the designs of tractors providing them with a wider wheel-base and a lower center of gravity, which makes newer tractors less prone to overturn, but not overturn-proof. Tractor manufacturers do provide general guidance on operating their tractors on slopes in the owner's manuals that come with the tractor.
There has been research done in the past looking at sensors or other instruments, such as clinometers, that indicate when a tractor is about to overturn. However, these types of sensors have been used more for educational purposes rather than as standard equipment on new tractors. One reason these types of instruments are not placed on tractors is that the sensor, or clinometer, only tells the operator that the tractor is about to overturn, but cannot tell the operator what corrective action to take to prevent the overturn. A second reason is that, in general, there is not sufficient time for the operator to react and prevent the overturn when the sensor indicates an overturn is occurring (most fatal tractor overturns occur in less than 1 second). Finally, clinometers may give the operator a false sense of security when operating a tractor on a steep slope since it cannot account for sudden changes in terrain, or obstacles on the slope (e.g., holes, rocks, logs) that can suddenly cause the tractor to overturn. That is why a ROPS is considered the most effective means of protecting an operator in the event of an overturn.
Posted 1/5/08 at 4:03 pm
I have wondered for a long time why we can pay farmers for conserving the land and water, and we do not offer direct subsidies to save the lives of farmers. I think funds could be made available through the USDA in a similar manner to conservation payments as a cost share for the practicem, if there was a political will to do it.
Posted 1/6/08 at 10:13 am
The blog by John Myers describes very well the development in the use of ROPS. As John mentiones, the development in the percentage of tractors with ROPS is encouraging, while the development in the tractor overturn fatalities is not as encouraging. The main reason is that the old non-ROPS tractors are not disappearing, and not retrofitted, and they are still involved in a lot of fatal overturns. I wanted to add another note: there might be a new problem with the open operator station FOLDABLE two-post ROPS that are now very comon on compact utility tractors and zero turn mowers. We have investigated two fatalities in Iowa where such tractors had the FOLDABLE ROSPS in DOWN POSITION. FACE reports of these cases are on the NIOSH FACE website. Since these cases, I have started to observe these tractors and mowers, not in a systematic way but wherever I see one.
It appears that a high percentage of the foldable ROPS are usually kept in the down position - which makes the ROPS ineffective if needed, and perhaps even more harmful than not having one. So - I have thought some type of warning system, similar to car seatbelt warning systems, could perhaps remind the operators that ROPS in the down position is a hazard.
Also, public awareness campaigns and education about this issues should perhaps be emphasized.
Posted 1/6/08 at 10:24 am
I am a farm safety professional AND a small farm operator. One of my own tractors does not have a ROPS; it is 50 years old, still works fine, and to the best of my knowledge nothing is available in the way of retrofit parts. I am cautious about how I use this tractor but recognize there is some risk. It's hard to think about just scrapping out this useful tractor. I know I can't afford to buy a newer one to replace it. So my choices are to try a non-approved shop built ROPS or just continue to be cautious. The use of non-ROPS tractors is a very tough problem to solve.
Posted 1/6/08 at 5:31 pm
I just wanted to make a clarification to one portion of the article:
The 8% figure is slightly misleading. This may be true for areas covered by Federal OSHA standards. However, many state-plan states have their own rules which do not have the enforcement limitations of Federal OSHA, and as such do inspect farms with fewer than 11 full-time employees.
Posted 1/12/08 at 4:06 pm
Thank you for your comment. You raise an interesting point about State-plan and Federal-plan programs, which we will include in our post. However, the impact is not as great as one might think. Based on what I have been able to determine, only three of the 21 state plans enforce their occupational safety and health standards on farms with fewer than 11 employees: California, Oregon, and Washington. While the remaining 18 state plans could choose to include farms with fewer than 11 employees, they would need to do so by using dedicated state funds, and no Federal funds. As I understand it, California, Oregon, and Washington support their agriculture OSHA programs with "state-only" funds. The other 18 states have chosen not to do this.
A second issue is that OSHA standards only apply to farms that have hired employees, even for state plans. Based on the 2002 Census of Agriculture, there were about 61,000 farms in CA, OR, and WA that reported using hired or contract farm laborer, which represents 39% of the farms in these three states (45% for California, 28% for Oregon, and 38% for Washington). This represents a significant coverage of farms in these three states. Still, these 61,000 farms represent just 3% of all farms in the United States. So, while it is important that these three states continue their programs, from a national perspective, the impact is limited.
Posted 1/13/08 at 12:08 pm
The best way to prevent tractor roll-overs is just to watch instructional videos prior to operating a tractor. Another way you could help is maybe if a balance indicator could be installed in a tractor, and when it was dangerously unbalanced then an alarm would sound.
Posted 1/12/08 at 9:59 pm
Thank you for your comment. Please see the reply to comment 5 regarding balance sensors/instruments.
Posted 1/13/08 at 10:01 am