Tractor Rollovers Are Preventable

The agriculture sector continues to have the highest rate of fatal occupational injuries (23.2 per 100 000 full-time-equivalent workers, with 593 fatalities in 2016) and the highest rate of nonfatal work-related illnesses and injuries (6.1 per 100 full-time-equivalent workers, with 58 300 cases in 2016).¹ Tractor deaths are responsible for approximately one third of these fatalities, with about half caused by tractor rollovers. Tractor rollovers occur for a number of reasons, including tractor operations near irregular, slippery, and sloped terrain; fixed pathway obstacles; and operator issues such as distraction, excessive speed, improper hitching, and failure to set the break when stopped (https://www.osha.gov/laws-regs/regulations/standardnumber/1928/1928.51). The most frequent victims are elderly farmers, although notably youths and hired farm workers are also affected.²

Tractor rollovers are preventable. Rollover protective structures and systems (ROPS) offer an engineering solution that, along with seatbelt use, protects drivers and virtually eliminates the potential for fatal or severe injuries.³ It has been shown that engineering controls are the most effective means of controlling workplace hazards, followed by administrative controls (policies and practices) and, finally, personal protective equipment. Engineering controls are preferred because policies and personal protective equipment require promotion of their implementation, which is dependent on the availability of sound and effective protective equipment as well as the knowledge and impetus of workers to use it appropriately.

Some 4.2 million tractors are in use on US farms and ranches. By 1985, as a result of legislation and buy-in from the industry, all new tractors were being manufactured with ROPS. However, tractors have significant longevity, and only 59% had ROPS in place in 2006.⁴ International research suggests that further reductions in tractor rollover fatalities will not occur until 75% to 80% of eligible tractors are retrofitted with ROPS.⁵

Research has led to the development of effective retrofit designs, including cost-effective designs, structures that deploy automatically (auto-ROPS), and stability indicator sensors. Qualitative research has identified barriers to retrofitting old tractors with ROPS: the expense involved, spatial clearance for specific environments, tractor housings that can support ROPS and withstand overturning, personal preferences, and risk perceptions on the part of tractor operators. Implementation research in this realm has focused on social marketing, training and education (sometimes including targeting of high-risk populations), and, more recently, an ROPS rebate program.⁶

COST-EFFECTIVENESS

In this issue of AJPH, Myers et al. (p. 1517) estimate the cost-effectiveness of a rebate program and a social marketing campaign in preventing tractor-related fatalities and injuries. The marketing campaign targets at-risk segments of the farming community (small-scale crop and livestock farms), identifies barriers to prevention (e.g., pressure to reduce costs and save time), includes incentives (e.g., cost reductions through provision of rebates), crafts messages on dangers to families and the economic burden of disability, and makes use of dramatic visual images.

A pilot of several combinations of these campaign components in four regions of New York State led to a significant number of ROPS retrofits. The investigators calculated “exposure time”—the time between dates of retrofitting and three different end dates (date of an injury or event, date of the latest survey, and December 2017)—through an annual survey of individuals who had obtained ROPS through the rebate program and hotline callers. They used information about the 17 reported overturns in New York as well as data from Kentucky and the Centers for Disease Control and Prevention to estimate the probability of a rollover event. They also used occupational fatal and nonfatal injury cost estimates provided by Leigh et al.⁷

The investigators estimated injury costs by calculating the probability of an event among retrofits versus nonretrofits, determining the number of injuries prevented, and multiplying probabilities by cost estimates, with some adjustments. The study showed a cost savings for the New York social marketing campaign and rebate program of more than $6 million with respect to injuries averted versus a total program cost of approximately $1.8 million.

The Myers et al. intervention study should serve as a model for implementation research in public health. Their investigation focused on a circumscribed problem; incorporated conceptual frameworks, mixed methods, and cost–benefit analyses; included multiple interventions in various combinations and focused on broad geographical swaths and subpopulations; combined substudies conducted by investigators from a wide array of disciplines; and involved a longitudinal time line, with funding secured over time. These elements are essential to amassing the kind of evidence needed to evaluate public health interventions with all of their “moving parts.”

More specifically, the Myers et al. investigation focused on a public health problem that has been recognized around the world and has remained unsolved for almost a century. As is the case with many public health issues, we know what we have to do. As a moral society, and with growing appreciation of crop agriculture as a means of improving the quality and longevity of life in the United States, we need to protect the health of one of our most precious commodities: the US workforce. The goal of outfitting more than 80% of old tractors with ROPS is attainable and, now, demonstrably cost-effective. It is certainly worth the price.