A field study was done to evaluate different seat designs in the aspect of minimizing vibration transmission and reducing the level of discomfort experienced by drivers subjected to transient vibration. Two seat designs (sliding or fixed in the horizontal direction) were compared in an experiment based on variation of sitting posture, speed, and type of obstacle. The comparison was done by assessing discomfort and perceived motion and by vibration measurement. Ten professional drivers were used as participants. Maximum Transient Vibration Value and Vibration Dose Value were used in the evaluation. The results showed that a sliding seat is superior in attenuating vibration containing transient vibration in the horizontal direction. It was also perceived as giving less overall and low back discomfort compared to a fixed seat.