Physiological Effect of Vibrations on Tractor Drivers under Variable Ploughing Conditions: Mohammad MUZAMMIL, et al. Department o f M e c h a n i c a l E n g i n e e r i n g , E r g o n o m i c s Laboratory, Faculty of Engineering & Technology,Aligarh Muslim University, India-The vibration conditions to which tractor operators are subjected are complex and varied with multi axis translation and rotational vibration inputs to different parts of the body. Working under such conditions may lead to human fatigue and other driving related hazards. The present research was carried out to study the operators under varying conditions of vibration while driving a tractor with and without farm equipment on different fields. Test runs were conducted in wet and dry fields to determine the levels of vibration generated at different engine speeds. On the basis of this study three levels of vibration namely 2.5, 3.5 and 5.0 m/s 2 were selected. Five subjects, all males, with no experience in the field of tractor driving participated in the study. The data were analyzed on the basis of three factor repeated measure kind of experimental design. The results showed that the main effects of farm equipment and the vibration level were statistically significant but the effect of field type was found to be statistically nonsignificant. The results of the study call upon the ergonomists to design and develop a tractor where the driver may be relieved of vibration induced stresses. Front loading of farm equipment is recommended for improved visibility and better working posture. (e-mail: mmuzammil18@yahoo.co.in) associated with agriculture or related trades. Farm workers functioning as the drivers of agricultural tractors are exposed to whole body vibrations, which may be extremely severe depending upon such factors as the attached farm equipment, speed of travel, condition of the field, etc. These vibrations are extremely complex and varied, with multi-axis translational and rotational vibration inputs to different parts of the body. Working under such an environment results in human fatigue, which contributes to driving related accidents and other health hazards. The vibrations produced by tractors and other off road vehicles and earth moving machinery were found to have a detrimental effect on the driver's performance (Rosegger and Rosegger; Grandjean; Goglia et al.) [1][2][3] . Decrements in occupational performance were also observed by Wertheim 4) while evaluating the effect of the moving environment on operators. Several studies conducted by Milosevic 5) on drivers of heavy vehicles revealed significant changes in body temperature, diastolic blood pressure and an increase in accommodation visual reaction time after prolonged driving. Longer exposure duration while performing ploughing and harrowing operations may also cause severe discomfort, pain and injury (Mehta et al.) 6) . Increased risks for low back pain (LBP) disorders were reported by Bovenzi 7) among tractor drivers due to continuous exposure to whole bo...