Getting behind the wheel when drowsy is just as dangerous as drunk driving, according to a new study that found young drivers do not recognise the dangers of fatigued driving.
Driving sleepy and driving drunk were two risky behaviours linked to a comparable increase in crash risk, yet drivers perceived the dangers of each as vastly different, researchers said.
"Research shows a blood alcohol content (BAC) of 0.05 per cent has the same effect as being awake for 17 hours, and a BAC of 0.1 per cent is roughly 20 hours, but drivers don't consider the impairment to be the same," said Chris Watling, from the Queensland University of Technology in Australia.
"In Queensland, 20 per cent of the state's fatal crashes were attributed to drink driving and an estimated 15 per cent to fatigued driving, although incidence rates of sleep-related crashes are often more difficult to pinpoint because of the absence of an objective test," said Watling.
The study, which examined the perceptions of sleepy driving and drink driving of 114 young drivers (under 30) and 177 drivers over 30, found young drivers were more likely to drive sleepy than drunk and more accepting of enforcement practices for drink driving than they are for sleepy driving.
"What this shows is that drivers, in particular young drivers, don't view equally the dangers of drink driving and sleepy driving despite the crash risks being similar," said Watling.
Watling said sleepiness had been shown to significantly impair a person's cognitive and psychomotor abilities, which impact safety-critical tasks such as driving, attention, working memory and coordination.
He said younger drivers were also more likely to be impaired by sleepiness because of the natural developmental maturing of the body's sleep-wake systems in early adulthood.
"Given younger drivers are over-represented in crash statistics and more likely to be impaired by sleepiness, it is vital we look to increase their perception of the dangers of driving while sleepy," said Watling.
"The positive take home message is that these results reflect the efforts of sustained drink-driving enforcement and community education campaigns that have changed social norms and reduced the acceptability of drink driving," he said.
"However, it also highlights a greater need to increase all drivers' perceptions of the dangers of sleepy driving," he said.
"Unlike drinking alcohol, sleep is a vital human need. Everyone has to sleep and no single person is immune to the effect of sleepiness - the impairment from sleepiness needs to be respected in the same way as the impairment from drink driving," he said.
