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Determining the Effectiveness of Mirrors and Camera Systems in Monitoring the Rearward Visibility of Self-Propelled Agricultural Machinery

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan

Citation:  Journal of Agricultural Safety and Health. 23(3): 183-201. (doi: 10.13031/jash.12034) @2017
Authors:   Shawn G. Ehlers, William E. Field
Keywords:   Blind spot, Cameras, Hazard detection, Machinery runovers, Mirrors, Operator vision, Rearward vision, Vehicle backover incidents, Visibility.

Abstract. This study concerned the ability of operators of tractors and other self-propelled agricultural machinery to visually recognize objects and/or hazards within close proximity to the rear of those machines and/or any implements in tow, especially when backing up. It was hypothesized that the data collected would identify the factors affecting rearward visibility and help determine the effectiveness of two backup-assisting devices (i.e., mirrors and camera systems) in enhancing the operator‘s ability to observe objects or hazards. The study‘s experimental design involved the following: (1) selecting nine self-propelled machines for testing (five tractors of varying sizes, a combine, a sprayer, a skid steer loader, and a UTV); (2) laying out a five cell by five cell test grid behind each machine, with an indicator pole centered in each cell; (3) positioning the mirrors (exterior/interior) and camera system (camera and display monitor) for maximum visibility; and (4) collecting images from a 50th percentile male operator‘s eye midpoint position. The findings were recorded graphically onto a master grid for the backup-assisting devices (both individually and in combination) on each machine. Analysis of the results confirmed that various issues related to the machines impact the effectiveness of mirrors and camera systems in enhancing rearward visibility. Among them are the operator station‘s design and configuration, seat adjustability, optional accessories, exterior lighting, type of implement in tow, hitching method, and highway transport mode. These findings led to recommendations relative to each of the mirrors and camera systems, as well as observations of operator interactions with accessories and perceived effects on the operator‘s ability to view obstructed areas in close proximity to the machinery.

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