The young men all deny they are going to fall asleep. Dr. Reyner has a video recording of one trying not to. At first the person at the wheel is very upright, wet and bleary eyes determinedly fixed on the windscreen. Then he begins to blink briefly, every now and again; then for longer, and more often, with a slight drop of the head. Each nod grows heavier than the last. The blinks become a 10-second blackout. Every time, he jerks awake as if nothing has happened. But the car, by the second or third occasion, has shot off the carriageway.