Roll over protection structure
Roll Over Protection Structure (ROPS) refers to operator compartment structures (usually cabs or frames) intended to protect equipment operators and motorists from injuries caused by vehicle overturns or rollovers.
Commonly found on heavy equipment (i.e. tractors) and UTVs used in construction and agriculture, 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.
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.
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 recent Cochrane Systematic Review confirmed that in one Swedish study there was evidence that legislation mandating ROPS on new tractors decreased the fatality rate immediately and further reduced the rate over time.
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, in effect shattering the rear window at the same time.
ROPS are commonly fitted to 4x4's, pickup trucks 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. 
See also 
- See OSHA Roll-Over Protective Structures, Direct Final Rule.
- 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 R, Lehtola MM, Day LM, Schonstein E, Suutarinen J, Salminen S, Verbeek JH. Interventions for preventing injuries in the agricultural industry. Cochrane Database of Systematic Reviews 2008, Issue 1. Art. No.: CD006398. doi:10.1002/14651858.CD006398.pub2.
- "CDC - Agricultural Safety: Cost-effective Rollover Protection Structures". NIOSH. Retrieved 10 January 2013.
- "History of ROPS". Minecorp.
- 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