The study, published today by the British Medical Journal (BMJ), found that drinking caffeinated drinks like coffee or tea was linked to a 63 per cent lower crash risk.
Long distance drivers routinely experience monotonous and extended driving periods in a sedentary position, which has been linked with drowsiness and an increase in the likelihood of crashing.
Previous studies have recognised that the use of caffeine is an effective strategy for improving alertness, but have been inconclusive in relation to the effects of caffeine to reduce the likelihood of injury. This study investigated, among other factors, the effects of caffeine on the likelihood of a crash in long distance commercial vehicle drivers.
The study was conducted between 2008 and 2011 in New South Wales and Western Australia. Participants were long distance drivers whose vehicle mass was at least 12 tonnes. The study compared 530 drivers who crashed their vehicle while on a long distance trip with 517 drivers who had not had a crash in the previous 12 months.
After adjusting for factors such as age, sleep patterns, symptoms of sleep apnoea, kilometres driven, breaks taken, and night driving schedules, the researchers found that drivers who consumed caffeine to help them stay awake were 63 per cent less likely to have had a crash than drivers who did not take caffeinated substances.
Drivers who had crashed recently were, on average, nearly two years younger than drivers who had not, and were more likely to have had a least one crash in the past five years. Drivers who had not crashed recently had more driving experience, and tended to drive longer distances than those who had crashed, but reported fewer hours sleep per night and more difficulty staying awake while driving.
Forty three percent of drivers reported consuming substances containing caffeine, such as tea, coffee, caffeine tablets, or energy drinks for the express purpose of staying awake.
Lisa Sharwood researcher at The George Institute and lead author of the paper, said that this suggests drivers are making behavioural adaptation in order to manage their fatigue.
“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 said.
The researchers concluded that the consumption of caffeinated substances “can significantly protect against crash risk for the long distance commercial driver” and this has “important implications for the improvement of fatigue management strategies for this and similar populations.” Researchers also said, however, that this benefit is only useful for a short time and that having regular breaks, napping and appropriate work schedules are strongly recommended.
The study also looked at the effect of other factors, such as heavy cigarette smoking and a recent history of crashing. Researchers found that heavy cigarette smoking alone showed a relationship with crash risk, though this did not remain after adjusting for several confounding factors. Having had a crash in the last five years, however, increased the risk of crash by 81 per cent and remained significant even after adjusting for other factors.
