Aiming to evaluate the alteration of the visual field of a tractor occasioned by the installation of a cabin were determined the null visibility areas due to the presence or not of this structure, for each visual field. The procedures adopted were based on ISO 5721-1981 - Agricultural tractors - Operator's field of vision. The cabin increased in 34,42% the area of null visibility. The relationship projection area of tractor/total shadowed area was 0,075 to the tractor without a cabin, and 0,057 for the tractor with cabin, indicating the best conditions of visibility of the first in relation to the second. With respect to the visual area, the largest reduction happened in the eyes visual field and in the obtained with the head movement in function of the cabin supports and the rollover protection structure. The cabin decreases the operator’s area of vision, and adjustments in the project of the structure evaluated are necessary to improve the visibility conditions.
visual field; agricultural tractors; ergonomics
