Tractor rollovers are the single deadliest type of injury
incident on farms in the United States. The latest figures
from the National Institute of Occupational Safety and Health
(NIOSH) suggest there are approximately 250 tractor rollover
fatalities per year. NIOSH estimates that there are approximately
4.7 million tractors in use on U.S. farms; one-half of them
are without rollover protection for the operator. This fact
sheet will closely examine tractor rollover protection issues.
Rollover Protection Structures (ROPS) are roll bars or roll
cages designed for wheel- and track-type agricultural tractors.
ROPS are designed to create a protective zone around the operator
when a rollover occurs. When used with a seat belt, the ROPS
will prevent the operator from being thrown from the protective
zone and crushed from an overturning tractor or from equipment
mounted or hooked to the tractor (see Figure 1).
Figure 1. A buckled seat belt keeps the operator within
the zone of protection of the ROPS during an overturn.
Three types of ROPS frames are available: a two-post frame
(with solid fold down versions), a four-post frame, and a
ROPS with enclosed cab. They all serve the same function:
protecting the operator in case of a tractor rollover.
- National data suggests that 1 of every 10 tractor operators
overturns a tractor in his or her lifetime.
- Tractors in the Northeast states have the highest rate
of overturn deaths and the lowest percentage of tractors
- The one time effort in installing a ROPS will protect
whoever drives the tractor for the life of the tractor.
- The use of ROPS and a seat belt is estimated to be 99%
effective in preventing death or serious injury in the event
of a tractor rollover.
- The Occupational Safety and Health Act (OSHA) requires
an approved ROPS for all agricultural tractors over 20 horsepower
that were manufactured after October 25, 1976, and which
are operated by a hired employee.
- A ROPS normally limits the degree of rollover thereby
reducing damage to the tractor.
- A ROPS with enclosed cab also prevents tractor operators
from being knocked out of their tractor seat from rough
ground and low hanging tree limbs, provides protection from
the sun and other weather hazards, and reduces risk for
the unsafe practice of extra riders on tractors (see Figure
Figure 2. A ROPS with enclosed cab gives the operator the most
protection from common hazards of tractor operation.
Between 1967 and 1985 U.S. farm tractor manufacturers provided
ROPS as optional equipment on most tractor models. This meant
that new tractor purchasers had to add the cost of a ROPS onto
the base price of a tractor. Because most farmers are cost conscious,
few added ROPS as an option. Even fewer pre-1967 tractors have
ROPS, yet many of these tractors are still in use. Beginning
in 1986, American tractor manufacturers began voluntarily adding
ROPS on all farm tractors sold in the United States over 20
The percentage of tractors in use and manufactured before the
voluntary ROPS agreement is high because farm tractors are often
in use for 30 to 40 or more years. Many newer tractors originally
sold with ROPS have been stripped of the protective roll bar
or roll cage because some farmers claim the ROPS structure blocks
their view during normal tractor operations. Another reason
often given for removing a factory-installed ROPS is that the
tractor won't fit into smaller spaces with a bulky roll bar.
Foldable ROPS are now available to reduce this problem (see
Figure 3. A foldable two-post ROPS allows tractor operation
in low clearance situations without completely removing the
ROPS are engineered to mount on specific tractor models and
designed to operate with the tractors mounting brackets and
frame. This provides a structure that is flexible, yet rigid
enough to withstand the loads produced during a tractor overturn.
Prototype ROPS must pass engineered, crush, static, and dynamic
tests to assure adequate performance before they are produced
for the public. These prototype ROPS must meet the standards
set by the Society of Automotive Engineers (SAE) (SAE J167,
J2194), and the American Society of Agricultural Engineers (ASAE)
The dynamic test involves hitting the tractor ROPS in a prescribed
manner with a 4,410 pound pendulum weight from behind and from
both sides. In order for a ROPS to pass the dynamic test, the
ROPS protective zone must remain intact and maintain the specified
distances from the operator. The ROPS can be made of any material
as long as the material meets temperature requirements and passes
the tests set forth by the standards. Typical ROPS provided
by manufacturers are made of steel that will not fracture in
cold temperatures and are precision welded. The goal of the
ROPS is to absorb the impact energy without excessive deformation
to create a zone of protection for the operator.
Some ROPS frames and enclosed cabs are equipped with overhead
canopies to protect the operator from falling objects. Canopies
that protect against falling objects ñ called FOPS (falling
object protective structures) ñ must be properly designed and
certified. Such canopies are recommended when using front-end
loaders, working in the woods, or in other circumstances where
falling objects may be a hazard. FOPS must be designed according
to SAE and ASAE standards. To be sure that a canopy is a FOPS,
check with the ROPS supplier or the equipment dealer.
Farm tractors (including some lawn and garden models) should
have a factory installed ROPS with a seat belt. These ROPS are
certified to meet maximum rollover impact and dynamic forces.
Modification of the factory installed ROPS (cutting, grinding,
drilling or welding) is unauthorized and unwise. Modification
of the ROPS design can impair the ROPS ability to carry out
its function (i.e. providing a protective zone to save a human
life) in the event of a tractor overturn. Factory installed
ROPS will have a certification label attached to the roll bar
stating that the roll bar meets SAE/ASAE/ OSHA standards. See
Figure 4 for a typical example. It is important to check for
this label on imported tractors.
Figure 4. This certification tag indicates the ROPS meet
nationally approved standards for operator protection during
It is necessary to inspect and service a ROPS and seat belt
periodically to check for extreme rust, cracks, or other sign
of wear. Any of these could cause a failure of the ROPS during
a rollover. If there are signs of wear, the manufacturer or
dealer should be consulted to determine the suitable course
ROPS can also be abused or misused. Holes should never be drilled
into the ROPS frame, nor should a piece of steel be welded onto
the frame. If lighting or other light attachments are needed,
they should be clamped onto the ROPS. A ROPS should not be used
as a point of attachment for a chain, hook or cable. Pulling
with the ROPS could damage it and result in a rear overturn.
If a tractor with ROPS does overturn, the ROPS should be replaced
because it is specifically designed to bend to absorb the energy
generated by the tractor contacting the ground. ROPS are only
designed and certified to withstand a single overturn.
Many farm tractors manufactured since 1967 can be retrofitted
with a ROPS. Tractor companies and aftermarket manufacturers
have designed and developed ROPS for most tractor models. Manufacturers
such as AGCO, Case-IH, Kubota, New Holland and Deere and Company
offer low cost retrofit ROPS kits for tractors manufactured
from the mid 1960ís to 1985. ROPS for many older and smaller
tractors can be purchased for $600 or less. Agricultural equipment
dealers are approved to install a retrofit ROPS and seat belt.
Installation charges are normally in addition to the cost of
A listing of ROPS retrofits for farm tractors manufactured since
1967 has been compiled by the National Farm Medicine Center,
Marshfield, Wisconsin, in a publication called, A Guide to
Agricultural Tractor Rollover Protection. This guidebook is
available on the web at http://www.marshfieldclinic.org/nfmc/pages/default.aspx?page=nfmc_rops_guide
/. Local equipment dealers should also have
information on ROPS retrofitting for their brands of tractor.
ROPS for some older models of tractors may not be available
even though one is listed by a ROPS manufacturer. This is because
a ROPS manufacturer often will not produce a specific ROPS for
an older tractor until an order has been placed. An order for
just one ROPS may mean the cost will be prohibitive to the tractor
Because of the severe impact and dynamic forces present during
a rollover, it is important that a ROPS be properly designed,
manufactured, and installed. If the ROPS is too rigid or too
flexible, injury could occur to the operator during a rollover.
Homemade ROPS are not recommended because they may not be properly
designed, built, or installed. Poor welds and undersized bolts
could fail under the impact and stress of a tractor overturn.
Farmers, local hardware stores and welding shops do not have
the special steels, bolts or welding supplies required for an
approved ROPS. Nor do they have the testing equipment that is
needed to certify that a ROPS meets design standards. A homemade
ROPS also exposes the owner and builder of the ROPS to liability
damages should a tractor overturn and the homemade ROPS fail.
A seat belt is an integral part of the tractor rollover protective
system as it keeps the operator within the protective zone created
by the roll bar or roll cage. The seat belt assembly must also
conform to engineering standards.
A ROPS alone will not provide full protection to the operator
when there is a tractor overturn. A seat belt must be used in
combination with the ROPS to provide the highest degree of safety.
Without a seat belt, the operator will not be confined to the
protective zone, and may be crushed by the tractor or even the
Many farmers give the excuse that because they won't wear the
seat belt, they won't bother to install a ROPS. While a ROPS
alone won't completely protect the operator, it will provide
considerable protection. Precise statistics are not available
but what is known is that:
Few tractor operators buckle their seat belts while operating
There are an estimated 2,000 ROPS equipped tractor overturns
There is no data at the national, state, or local level to suggest
these ROPS equipped tractor overturns are fatal to the tractor
While roll bars and seat belts together are the most effective
system for operator protection from a tractor that is overturned,
the ROPS portion of the system provides the bulk of the protection.
Installation of a ROPS on all tractors is an important step
toward agricultural injury prevention.
Publication #: E42
The Pennsylvania State University is committed to the policy
that all persons shall have equal access to programs, facilities,
admission, and employment without regard to personal characteristics
not related to ability, performance, or qualifications as determined
by University policy or by state or federal authorities. It
is the policy of the University to maintain an academic and
work environment free of discrimination, including harassment.
The Pennsylvania State University prohibits discrimination and
harassment against any person because of age, ancestry color,
disability or handicap, national origin, race, religious creed,
sex, sexual orientation, or veteran status. Discrimination or
harassment against faculty, staff, or students will not be tolerated
at The Pennsylvania State University. Direct all inquiries regarding
the nondiscrimination policy to the Affirmative Action Director,
The Pennsylvania State University, 201 Willard Building, University
Park, PA 16802-2801, Tel 814-865- 4700/V, 814-863-1150/TTY.
Disclaimer and Reproduction Information: Information in
NASD does not represent NIOSH policy. Information included in
NASD appears by permission of the author and/or copyright holder.