The present study aimed at quantifying the matching between the physiological response of a car driver and the vehicle motion. Assuming that the performance of a head stabilization mechanism, the vestibulo-collic reflex, affects driving feeling, we recorded the activity of neck muscles that help maintain the head position. Electromyograms (EMGs) were recorded from the sternocleidomastoid muscles (SCM). Vehicle acceleration was recorded with a small accelerometer. Subjects were required to perform straight-line acceleration. The EMG response of a driver's neck muscle depended not only on vehicle acceleration but on its time derivative, jerk. A quantitative analysis showed that the EMG profile can be reproduced by a linear sum of acceleration and jerk. Our analysis indicated that the relationship between the muscle response and the vehicle motion can be characterized by two parameters: the optimal weight for the jerk term and the optimal time lag. The current study proposes a method for characterizing a physiological response of a driver to dynamic vehicle motion.