New research suggests consuming caffeinated substances,
like coffee, significantly protects against crash risk for
long-distance commercial drivers.
But University of Otago professor Jennie Connor warned
caffeine, while effective for short amounts of time, was not
a solution to fatigue.
The research, published in the British Medical Journal, was
undertaken in Australia between 2008 and 2011.
It compared 530 long-distance heavy vehicle drivers who had
crashed their vehicle on a long distance trip in the
preceding 12 months, with 517 such drivers who had not
Researchers linked drinking coffee to stay awake with a 63%
lower crash risk.
''Long-distance commercial drivers who consume caffeinated
substances such as coffee or energy drinks, to stay awake
while driving, are significantly less likely to crash than
those who do not, even though they drive longer distances and
sleep less,'' researchers said.
More than 40% of drivers reported consuming substances
containing caffeine for the express purpose of staying awake.
Lead researcher Lisa Sharwood, of the University of Sydney,
said it suggested drivers were adapting their behaviour to
''This may seem effective in enhancing their alertness, but
it should be considered carefully in the context of a safe
and healthy fatigue management strategy. Energy drinks and
coffee certainly don't replace the need for sleep,'' she
That notion was shared by Prof Connor, head of preventive and
social medicine at the University of Otago's Dunedin School
She had previously researched driver sleepiness and crashes
in New Zealand, and said although caffeine was one of the
most widely used substances by drivers to stay alert, its
effect was short-lived.
''It has to be a substantial amount of caffeine to make a
difference to alertness - about two cups of good coffee - and
it wears off fairly quickly, after about 45 minutes. To make
a significant difference to your ability to drive when
sleepy, you need more than a cup of coffee.''
Drowsy drivers were impaired, like drunk drivers, even if
they did not fall asleep at the wheel.
''That is to some extent reversible by caffeine for a short
period of time. It will provide you with a little bit of
extra alertness but it's not the answer because an hour later
you're back in the same situation,'' Prof Connor said.