A microphone picks up your answer and breaks it down into separate words with speech-recognition software. A camera built into the dashboard also tracks your lip movements to improve the accuracy of the speech recognition. A voice analyzer then looks for signs of tiredness by checking to see if the answer matches your profile. Slow responses and a lack of intonation are signs of fatigue.
This research suggests that we can make predictions about various aspects of driver performance based on what we glean from the movements of a driver’s eyes and that a system can eventually be developed to capture this data and use it to alert people when their driving has become significantly impaired by fatigue.