Tractor Rollover Protection: Is the Incorrect Use of Foldable Rollover Protective Structures Due to Human or to Technical Issues?

Abstract

Objective: To identify the critical behaviors that may hinder the correct use of foldable rollover protective structures (FROPS) on tractors and to explore the influence of user factors and FROPS technical characteristics. Background: FROPS are effective in preventing fatal injuries in rollover accidents if they are in the upright position. However, many farmers leave FROPS folded down. Method: Twenty farmers and sixteen models of tractors were involved in the study. Operators were observed while raising the FROPS, and the observed behaviors were correlated with user factors and FROPS technical features. Results: In the initial rotation of the FROPS, higher lowered roll-bar to ground distance and FROPS pivot-pin to ground distance required more awkward and unbalanced postures ( p = .02 and p = .01, respectively). When rotating the FROPS in upright position, smaller stature of the participants and higher FROPS pivot-pin to ground distance were significantly correlated with using the tractor’s rear 3-point lower links as a supporting surface ( p = .01 and p = .02, respectively). Conclusion: FROPS might be revised considering users’ comfort in use and anthropometric variability, to improve reachability, avoid risky behaviors, and enhance FROPS operation. Application: Technical solutions to enhance FROPS accessibility may be developed, particularly by providing safe surfaces to support operators and highlighting the grasping points. Further best practices and information on correct gestures to handle the FROPS should be included in the tractor manual.

Considering Human Variability in the Design of Safe Interaction with Agricultural Machinery: The Case of Foldable Roll-Over Protective Structure (FROPS) Manual Handling

“…The lower and upper parts are joined at a pivot point by a couple of pins on each side of the protective structure, making it possible to fold the upper part frontward or rearward, based on the FROPS type (Figure 1). The folding operation is generally manual, even though some dimensions and mass of the components may overcome the human handling capacity, as observed in previous works [16,17] on standard tractors. FROPS, as all ROPS, are designed to absorb the energy developed by the impact with the ground in case of overturn, but with a limited deflection to avoid the infringement of the "clearance zone", a standardised volume representing the space occupied by the driver "when seated either inside the envelope of the structure or within a space bounded by a series of straight lines from the outer edges of the structure to any part of the tractor that might come into contact with flat ground and that is capable of supporting the tractor in that position if the tractor overturns" [3] (p. 3).…”

“…Previous studies aiming to promote the comfortable and safe handling of rear-mounted FROPS resorted mainly to technical engineering approaches to develop mechanical solutions [32,33] to ensure the clearance zone is not infringed during strength tests and protect the operator in case of roll-over [12,34,35]. Although the ergonomic issues during FROPS operations have increasingly received attention [8,34], few previous studies stressed the role of anthropometric variability in determining the quality of the human-FROPS interaction; these studies highlighted the need for some redesign to enhance comfort and safe use, especially for shorter operators who are adopting awkward postures and unsafe climbing behaviours when handling the roll-bar [16,17]. The difficulties and the improper behaviours that emerged from these previous field observations represented the rationale of the present study and the resulting proposal of FROPS improvement.…”

“…The manual handling, considered a strenuous operation, and the poor reachability of the rearmounted FROPS have been recognised as the leading causes for removing or leaving the FROPS in a folded down position [22,23]. Reachability issues especially affect shorter operators, who reported the need to redesign the foldable roll-bar able to respect users' anthropometric variability [16,17]. FROPS, as all ROPS, are designed to absorb the energy developed by the impact with the ground in case of overturn, but with a limited deflection to avoid the infringement of the "clearance zone", a standardised volume representing the space occupied by the driver "when seated either inside the envelope of the structure or within a space bounded by a series of straight lines from the outer edges of the structure to any part of the tractor that might come into contact with flat ground and that is capable of supporting the tractor in that position if the tractor overturns" [3] (p. 3).…”

“…The manual handling, considered a strenuous operation, and the poor reachability of the rear-mounted FROPS have been recognised as the leading causes for removing or leaving the FROPS in a folded down position [22,23]. Reachability issues especially affect shorter operators, who reported the need to redesign the foldable roll-bar able to respect users' anthropometric variability [16,17].…”

Agricultural Tractor Roll-Over Related Fatalities in Italy: Results from a 12 Years Analysis

“…In detail, in our survey, 19.4% of the fatal accidents recorded that the tractors involved were fitted with a folding front two-post roll-bar fixed in a horizontal position, therefore, ensuring no protection in case of overturning. This is substantially due to negligence or carelessness of the drivers, who do not consider properly its safety role, or to other actual difficulties in folding/rising the protective structure, because of poor design or inconsistencies with human anthropometrics requiring awkward position or movements [32]. To try to solve this problem, a research work was carried out in order to design a nonfoldable ROPS for narrow-track tractors, which provides rollover protection all the time without making agricultural works more difficult.…”