of .08%, the legal limit. >> similar to alcohol intoxication, your reflexes, responses and data processing speed would be slower. >> 20% of accidents involve drowsy drivers, according to researchers here at verge yain tech. no sleep means bad moves on the road. awake for 21 hours, i got behind the wheel. i drove the 2.2 mile test track at virginia tech transportation institute. nearly an hour later, cameras installed inside the car captured my eye movements. slow blinking, one indication of a drowsy driver. >> put your turn signal on, that you're going to pass them. >> wrong thing. >> you start making errors. now you're drifting outside the lane a little bit. >> if i'm starting to kind of nod off, it follows my face down. >> virginia tech researchers are developing facial tracking