Abstract
Previous research suggests that while humans may be able to accurately assess whether or not slopes are traversable by foot, they are not as skilled at estimating the grade of slopes in degrees or percentages. This finding has practical implications for users of heavy power equipment who may operate such equipment on sloped terrain. Specifically, users who are unable to accurately estimate the grade of a slope where they plan to operate power equipment may put themselves in a dangerous position if the grade of such a slope exceeds the maximum permissible grade for safe equipment operation. In the present case a worker operated a power buggy on a slope that exceeded what was recommended by the manufacturer for operation. The operator was subsequently thrown from the equipment and was ultimate rendered a quadriplegic. We describe the method and results of a study conducted by our human factors personnel to determine the accuracy with which the “average” person is able to estimate and measure the grade of a slope. The implications of these findings for the present case are discussed. Additionally, the importance of adequate instructions, warnings, and feedback in the context of this unfortunate incident are discussed.
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