In 1993, approximately 132 agricultural tractor overturn fatalities occurred per year (Myers and Snyder, 1993). Ten years later, the number of fatalities is still in excess of 100 each year (Myers, 2003). The use of rollover protective structures (ROPS) on farm tractors, along with operator seat belt use, is the best known method for preventing these fatalities. One impediment to universal ROPS use, however, is low-clearance situations, such as orchards and animal confinement buildings. These agricultural low-clearance environments, involving "low-profile" tractors where traditional ROPS may not be feasible, are exempted from ROPS use as stated in OSHA 1928.51(b)(5)(i & ii). To address the need for ROPS that are easily adapted to lowclearance situations, the Division of Safety Research (DSR), National Institute for Occupational Safety and Health (NIOSH), developed a passive safety device to protect tractor operators in an overturn event. The automatically deploying, telescoping ROPS (AutoROPS) consists of two subsystems. The first is a retractable ROPS that is normally mounted to the tractor axle and latched in its lowered position for day-to-day use. The second subsystem is a sensor that monitors the operating angle and rate of roll on two axes of the tractor. If an overturn condition is detected by the sensor, the retracted ROPS will deploy and lock in the full upright position before ground contact. The AutoROPS has been tested under both field and laboratory conditions prescribed in the ROPS performance industry standard, SAE J2194.

The adoption of such a new agricultural safety device is based upon compliance with the existing industry standards and the development of new performance standards when necessary. This presentation will describe the process of:

  • determining the necessary standards for design and testing criteria,

  • interpretation of the chosen standards,

  • implementing the testing procedures described in the standard to new and existing agricultural safety devices or systems, and

  • developing new performance standards in conjunction with the American Society of Agricultural and Biological Engineers (ASABE).


Tractor overturns are the leading cause of fatalities in the agricultural industry. Approximately 132 fatalities occur per year (Myers and Snyder, 1993). The use of a rollover protective structure (ROPS), along with concurrent seat belt use, is a system with the potential of preventing these fatalities. Although ROPS use is increasing (Zwerling, et al., 1997), the number of overturnrelated fatalities per year has not been declining significantly (National Safety Council, 1997).

One impediment to ROPS use is low-clearance situations, such as orchards and animal confinement buildings. Many smaller tractors are now equipped with manually extending or foldable ROPS for use in such situations. However, between 10% and 20% of new tractors are reported to be operating without ROPS (Myers and Snyder, 1993). Decreased use or non-use of manually extending or foldable ROPS may occur because of a need to operate these tractors in low-clearance situations. A ROPS will only provide protection if the operator chooses to properly deploy them.

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