Agricultural tractor overturns kill more than 100 workers each year in the United States. Rollover protective structures (ROPS) can prevent most of these deaths but can be expensive in retrofit applications. Cost-effective ROPS (CROPS) have been designed and built at the National Institute for Occupational Safety and Health but performance must be evaluated. This study: (1) evaluated CROPS performance, (2) developed a simulation model for probabilistic CROPS evaluation, and (3) evaluated exemplar prototype CROPS performance via simulation of testing requirements. The CROPS prototype evaluated in this study was a Ford-3000 CROPS prototype design. Simulations based on ROPS performance standard SAE J2194 (Society of Automotive Engineers) identified scenarios where the Ford-3000 CROPS might fail. No failure scenarios were identified during simulation of ROPS performance testing to Occupational Safety and Health Administration (OSHA) test procedures and performance requirements. Despite passing experimental SAE J2194 testing, computer simulations found scenarios where the Ford-3000 CROPS prototype design might fail. Re-design of the Ford-3000 concept is necessary before field implementation.

There are approximately 4.2 million tractors on farms and ranches across the United States. The average age of tractors is over 25 years and some of the oldest models are the most popular. Older tractors are less safe than newer tractors, and many older tractors are operated by individuals with increased risk of being injured or killed on a tractor. A key tractor safety device, a rollover protective structure (ROPS), is missing from most tractors manufactured before 1985. Data from the US Department of Labor's Census of Fatal Occupational Injuries (CFOI) suggest that the production agriculture sector accounts for approximately 70.3% of the 3299 work deaths in the Agriculture, Forestry, and Fishing industry between 2003 and 2007. Nearly 900 of these incidents involve farm tractors and of these, approximately 43% were from tractor overturns. Efforts to reduce both the number of tractor overturn fatalities and injuries have been underway for years. These efforts primarily encompass worker education/training programs and activities, ROPS design and engineering applications, and research on more effective ways of encouraging tractor owners to retrofit their older tractors with ROPS. This paper reviews various approaches available to reduce the fatalities, serious injuries, and economic burden associated with tractor overturns. Past and current efforts to promote ROPS in the United States and in other countries, current safe tractor operations education and training programs, and ROPS-related safety engineering projects are discussed. Recommendations for advancing safe tractor operation and the number of tractors protected by ROPS are given. This review was prepared for the Agricultural Safety and Health Council of America/National Institute for Occupational Safety and Health conference, "Be Safe, Be Profitable: Protecting Workers in Agriculture," January 2010.

Agriculture remains one of the most hazardous occupations in the U.S. By conservative estimates, tractor overturns alone claim 120 lives annually. A rollover protective structure (ROPS) and a seatbelt are a highly effective engineering safety control that can prevent many of these fatalities and reduce the severity of injuries associated with tractor overturn. SAE J2194 is a consensus performance standard established for agricultural ROPS. According to this standard, satisfactory ROPS performance can be demonstrated through static testing, field upset testing, or impact testing. A previous modeling study suggested that static testing may underpredict the strain induced in a ROPS during a field upset. In the current study, field upset testing and laboratory static testing results were compared. Field upset testing included six rear and six side upset tests performed according to SAE J2194 guidelines. Additionally, static testing was performed on a ROPS of the same model. The results support findings from the modeling study. Near the lowest sections of the ROPS, the plastic strain resulting from rear upset testing exceeded the plastic strain from static testing for 18 of 24 data points. Conversely, the ROPS plastic strain from side upset testing was typically less than plastic strain from laboratory static testing. However, data indicate that the side upset test may not be very repeatable. This study suggests that the longitudinal loading energy criterion for static testing might not be a conservative predictor of rear upset ROPS response.