Effect of Vibration Stimulus in Lowering Alertness Levels of Drivers

The authors of the present paper report the measured physiological phenomena of a driver falling into the lowered alertness level and they evaluate the effectiveness of vibration stimulus added to a driver in the low alertness level as a means to keep the driver awake.

From the survey test for 21 subjects, it was found the awakening whole-body vibration by the addition of which the alertness level of a driver could be heightened effectively, and it existed in the range between the amplitude of 1 to 15 mm and the frequency of 1 to 4 Hz.

From the driving tests on road for 10 drivers under variable conditions of lack of sleep and much fatigue, the following results were obtained;

1. (1)
   The characteristic behavior of a driver falling into a drowsy state was observed to be a typical zigzag driving in the lane with a lowering of the alertness level.
2. (2)
   The lowering of the alertness level was closely related to the decrease of the horizontal eye-movement and corresponded to α-activation in the EEG.
3. (3)
   it was proved experimentally that the exposure of a driver to the above mentioned vibration was effective to heighten the lowered alertness level.
4. (4)
   This effect was maintained for 2 to 10 minutes after the vibrational stimulations for the subject drivers during severe drowsy conditions in this experiment.