La. Reyner et Ja. Horne, FALLING ASLEEP WHILE DRIVING - ARE DRIVERS AWARE OF PRIOR SLEEPINESS, International journal of legal medicine, 111(3), 1998, pp. 120-123
Falling asleep at the wheel is a common cause of road accidents, but l
ittle is known about the extent to which drivers are aware of their sl
eepiness prior to such accidents. It is an area with medico-legal impl
ications. To simulate this situation 28 healthy young adult experience
d drivers, sleep restricted the night before drove for 2 h in the afte
rnoon in an interactive real-car simulator incorporating a dull and mo
notonous roadway. Lane drifting, typifying sleepy driving, was subdivi
ded into minor and major incidents, where the latter was indicative of
actually falling asleep. A distinction was made between the subjectiv
e perceptions of sleepiness and the likelihood of falling asleep which
drivers reported separately. Increasing sleepiness was closely associ
ated with an increase in the number of incidents. Major incidents were
preceded by self-awareness of sleepiness well beforehand and typicall
y, subjects reached the stage of fighting sleep when these incidents h
appened. Whilst the perceived likelihood of falling asleep was highly
correlated with increasing sleepiness, some subjects failed to appreci
ate that extreme sleepiness is accompanied by a high likelihood of fal
ling asleep. It was not possible for our subjects to fall asleep at th
e wheel and have an ''accident'' without experiencing a sustained peri
od of increasing sleepiness, of which they were quite aware. There is
a need to educate at least some drivers that extreme sleepiness is ver
y likely to lead to falling asleep and a high accident risk.