Rollover protection structure
A rollover protection system or rollover protection structure (ROPS) (// or //) is a system or structure intended to protect equipment operators and motorists from injuries caused by vehicle overturns or rollovers. Like rollcages and rollbars in cars and trucks, a ROPS involves bars attached to the frame that maintain a space for the operator's body in the event of rollover.
Commonly found on heavy equipment (i.e. tractors), earth-moving machinery and UTVs used in construction, agriculture and mining, ROPS structures are defined by various regulatory agencies, including the US Occupational Safety and Health Administration (OSHA). The regulations include both a strength requirement as well as an energy absorption requirement of the structure. Some dump trucks add a protrusion to their boxes that cover the operators compartment for ROPS purposes.
ROPS are commonly fitted to 4x4's, pickup trucks, Earth moving equipments, soil compactors and utes used in the mining industry. Products such as this were developed out of necessity so employees travelling around or within mine sites were provided with extra protection in the event of a fleet vehicle roll over. 
In the US, ROPS designs have to be certified by a Professional Engineer, who will normally require a destructive test. The structure will be tested at a reduced temperature (where the metal is more brittle), or fabricated from materials that have satisfactory low temperature performance.
In Australia and most other countries, International Organization for Standardization has guidelines for destructively testing ROPS structures on earthmoving machinery, excavators, forestry equipment and tractors. Theoretical performance analysis of major new design ROPS is not permitted as an alternative to physical testing.
Tractor rollover deaths have been identified as a public health problem since the 1920s. Research efforts from several countries towards the development of engineering controls to reduce injury from rollover persisted for several decades before any legislation took place. In 1959, Sweden became the first country to enact ROPS legislation, requiring all newly manufactured tractors in the country to have ROPS installed. This requirement was expanded in 1965, requiring all tractors in Sweden, regardless of manufacture date, to have ROPS installed if it was operated by an employee and not the actual owner.  Similar legislations requiring ROPS installation have been enacted in Australia, Germany, and Denmark.
In the United States, standards for ROPS design and utilization for tractors were first developed in 1967 by the American Society for Agricultural Engineers. ROPS legislation was passed in 1975, with OSHA requiring that all tractors manufactured from October 25, 1976 onwards be equipped with ROPS. In 1985, the development of a new voluntary safety standard by the American Society of Agricultural Engineers (S318.10) encouraged an initiative by American tractor manufacturers to equip new tractors over 20 horsepower with ROPS. Since then, additional efforts have been made to help increase the adoption of ROPS among tractor owners who are still not using it. In 1993, the five largest North American tractor manufacturers started an incentive program offering ROPS retrofit kits to local dealers to sell to tractor producers, without additional cost. The response by tractor owners to this retrofitting initiative was limited.
In 2006, the New York ROPS Rebate Program was launched in an effort to increase access of ROPS among New York tractor operators; this need was addressed as the Northeast United States has consistently reported lower rates of ROPS usage than other regions of the United States. The program has since then expanded to six states including NY, PA, VT, NH, WI, and MA. This rebate program will provide up to 70% of the cost of purchase, shipping, and installation up to a cap of $865.
Rollover injury and fatality
Tractor rollover has become one of the leading causes of occupational death in the agricultural industry. In the United States from 1992 to 2005, 1412 workers were killed from tractor rollover, with roughly 10,000 suffering an injury. These rollover fatalities represented about 20% of all agricultural fatalities.  During 2003 to 2010, 933 workers in agriculture, forestry, fishing and hunting industries were killed as a result of tractor rollover, accounting for over 63% of all tractor-related deaths. The National Safety Council estimates that between 150 to 200 tractor operators are killed due to rollover in the U.S. each year. Researchers have also attempted to estimate the chances that a tractor rollover will result in a fatality of the operator. An adjusted probability of about 8 deaths per 100 tractor overturns (8%) was extrapolated using data from the Kentucky Fatality Assessment and Control Evaluation (FACE) Program.
The National Institute for Occupational Safety and Health (USA) believes that ROPS and proper seat belt use on tractors can eliminate nearly all fatalities caused by tractor and lawn mower overturns. Without a seatbelt, the rider may be thrown from the tractor during the overturn, and thus left unprotected by the ROPS. NIOSH estimates that fatality rates from tractor overturns could be reduced by a minimum of 71%, if all tractors were equipped with ROPS. A Cochrane Systematic Review confirmed that in one Swedish study there was low quality evidence that legislation mandating ROPS on new tractors decreased the fatality rate immediately and further reduced the rate over time.
Research from Sweden shows that the fatality rate from tractor rollover remains stable when ROPS prevalence rates range from 40% to 75%; only until the rate of ROPS adoption reaches 75% to 80% does the fatality rate from rollover fall significantly, to near-zero. The latest estimates of tractors equipped with ROPS in the United States show that 59% of tractors were ROPS-equipped in 2006, an increase from the 38% in 1993. With steady increases in the installation of ROPS, it is projected that the rollover fatality rate will decline steadily, until reaching a rate near zero by 2028.
ROPS usage has also appeared to be linked to a number of factors. There is regional variation in ROPS usage within the United States, as estimates from 2006 showed that tractor operators in the South had the highest prevalence of ROPS usage at 65%, while the Northeast had the lowest prevalence of ROPS usage at 51%. The West and Midwest reported rates of 60% and 56% respectively.
Age of tractor operator is a large risk factor, as increasing age shows to go along with decreasing rates of ROPS usage. The oldest group of tractor operators, those ages 65 and above, have the lowest rate of overall ROPS usage at 42%. Additionally, older tractor operators are more likely to suffer fatality and severe injury outcomes following tractor rollover than younger operators. Along with the age of the tractor operator, the age of the tractor itself is a risk factor. Older tractor models are less likely to be equipped with ROPS, possibly owing to impracticality in installation or to mandated installations in newer models. Further, older tractors are more dangerous than newer tractors, possessing more narrow front ends, higher center of gravity, and more prone to operational failure.
Economics also appears to be a major factor in rates of ROPS adoption. Farms with low value of sales, part-time operations, and smaller acreage are less likely to employ ROPS-equipped tractors than farms with high value of sales, full-time operations, and larger acreage. Additionally, farms that use more hired labor over non-hired labor (family) are found to have fewer fatal tractor overturns. Overall, farms that are more economically viable are more likely to install ROPS on tractors than smaller, lower-income farms.
Some tractor operators have raised concerns about using ROPS in low-clearance environments, such as in orchards and buildings. In response, NIOSH developed an Automatically Deploying Rollover Protective Structure (AutoROPS) which stays in a lowered position until a rollover condition is determined, at which time it deploys to a fully extended and locked position. It is currently working with manufacturers to streamline the commercialization of this technology. The Division of Safety Research branch of NIOSH has developed cost-effective rollover protection structures (CROPS) for four tractor models (Ford 8N, Ford 3000, Ford 4000, Massey Ferguson 135), in an effort to provide safety for older model tractors.
Some automobile models have begun to adopt the phrase, substituting system for structure in the ROPS acronym, notably the Volvo C70 convertible models, and Jaguar XK. Their ROPS structures consist of two pyrotechnically charged roll hoops hidden behind the rear seats that will pop up in the case of a roll-over to protect the occupants. If the roof is up, the system will still work, shattering the rear window at the same time.
- See OSHA Roll-Over Protective Structures, Direct Final Rule.
- "History of ROPS". Minecorp.
- Murphy, Dennis J.; Myers, John; McKenzie Jr, E.A.; Cavaletto, Richard; May, John; Sorensen, Julie (2010). "Tractors and Rollover Protection in the United States". Journal of Agromedicine 15 (3): 249–63. doi:10.1080/1059924X.2010.484309. PMID 20665310.
- Biddle, Elyce Anne; Keane, Paul R. (2012). "Action Learning: A New Method to Increase Tractor Rollover Protective Structure (ROPS) Adoption". Journal of Agromedicine 17 (4): 398–409. doi:10.1080/1059924X.2012.713842. PMID 22994641.
- The Swedish Work Environment Authority's regulation AFS 2004:06, page 10 (in Swedish)
- Alkhaledi, Khaled; Means, Kenneth; McKenzie, Eugene; Smith, James (2013). "Reducing occupational fatalities by using NIOSH 3rd generation automatically deployable rollover protective structure". Safety Science 51 (1): 427–31. doi:10.1016/j.ssci.2012.08.004.
- Loringer, Kelly A.; Myers, John R. (2008). "Tracking the prevalence of rollover protective structures on U.S. Farm tractors: 1993, 2001, and 2004". Journal of Safety Research 39 (5): 509–17. doi:10.1016/j.jsr.2008.08.003. PMID 19010124.
- Freeman, Steven A. (1999). "Potential impact of a ROPS retrofit policy in central Iowa". Journal of Agricultural Safety and Health 5 (1): 11–20.
- Sorensen, JA; Jenkins, PL; Bayes, B; Madden, E; Purschwitz, MA; May, JJ (2013). "Increases in ROPS pricing from 2006-2012 and the impact on ROPS demand". Journal of agricultural safety and health 19 (2): 115–24. PMID 23923731.
- "ROPS Retrofit Program".
- Myers, John R.; Hendricks, Kitty J. (2010). "Agricultural tractor overturn deaths: Assessment of trends and risk factors". American Journal of Industrial Medicine 53 (7): 662–72. doi:10.1002/ajim.20775. PMID 19894222.
- Cole, HP; Myers, ML; Westneat, SC (2006). "Frequency and severity of injuries to operators during overturns of farm tractors". Journal of agricultural safety and health 12 (2): 127–38. PMID 16724789.
- See National Institute for Occupational Safety and Health (US) NIOSH Program Portfolio: Traumatic Injury: Selected Research-to-Practice Efforts Addressing Traumatic Injury Problems: Automatically deployed roll-over-protection structure (ROPS).
- "CDC - NIOSH Science Blog - Preventing Death and Injury in Tractor Overturns with Roll-Over Protective Structures". NIOSH. Retrieved 10 January 2013.
- Rautiainen, Risto; Lehtola, Marika M; Day, Lesley Margaret; Schonstein, Eva; Suutarinen, Juha; Salminen, Simo; Verbeek, Jos H (2008). Rautiainen, Risto, ed. "Interventions for preventing injuries in the agricultural industry". Cochrane Database of Systematic Reviews (1): CD006398. doi:10.1002/14651858.CD006398.pub2. PMID 18254102.
- Sorensen, J. A.; May, J.; Ostby-Malling, R.; Lehmen, T.; Strand, J.; Stenlund, H.; Weinehall, L. W.; Emmelin, M. (2008). "Encouraging the installation of rollover protective structures in New York State: The design of a social marketing intervention". Scandinavian Journal of Public Health 36 (8): 859–69. doi:10.1177/1403494808089655. PMID 19004904.
- "CDC - Agricultural Safety: Cost-effective Rollover Protection Structures". NIOSH. Retrieved 10 January 2013.
- "picture of broken c70 window and deployed ROPS". Retrieved 21 September 2014.
- The Kentucky ROPS Guide
- Legislation in the EU: Council Directive 87/402/EEC of 25 June 1987 on roll over protection structures mounted in front of the driver's seat on narrow-track wheeled agricultural and forestry tractors. It was modified several times, for the latest version refer to the consolidated version.
- ROPS test procedure (US State of Washington)
- ROPS Decider