Commercializing an Automatically Deployable Rollover Protective Structure (AutoROPS) for a Zero-Turn Riding Mower: Initial Product Safety Assessment Criteria

Fatal injuries have occurred to operators of zero-turn riding mowers when these machines rolled over during high speed sharp turns or on uneven terrain. These mowers are frequently operated in low clearance conditions such as around trees and when loaded onto low-roofed trailers. The automatically deployable rollover protective structure (AutoROPS) can provide both protection during rollover events and the capability to operate a mower in low clearance conditions. Until recently, AutoROPS technology development has occurred only in a government laboratory. In the current phase of development, private industry has taken an interest in the AutoROPS technology and is pursuing, with NIOSH, the product testing and development needed to commercialize the AutoROPS on a zero-turn riding mower. The government’s role, as a partner with private industry in bringing new safety technology into practical application, is discussed. Importantly, for the AutoROPS product to be as effective as possible, it should not introduce additional, unacceptable risks. Previous product safety assessments led by government laboratories are reviewed. These assessments were made to minimize hazards in products developed in government labs. A product safety assessment was performed on the AutoROPS during its design phase. In addition to minimizing the severity and frequency of operator injury resulting from an accidental rollover, the assessment considered 1) environmental factors such as corrosion, electromagnetic interference, and vibration; 2) human error avoidance; and 3) safeguard reliability analysis. This assessment was a cooperative effort between the safety engineering design team at the Division of Safety Research of the National Institute for Occupational Safety and Health; a ROPS manufacturer; and a zero-turn riding mower manufacturer. Design features are being incorporated into the prototype AutoROPS to address hazards encountered in normal use of these machines.