Truck drivers who consume large amounts of caffeine are more likely to have an accident, according to a study from the Virginia Tech Transport Institute in partnership with Loughborough University.
The study of more than 3,000 truck drivers found that high-caffeine consumers (those on five or more caffeinated drinks a day) felt sleepier and reported shorter amounts of sleep at night, and had poorer general health. They are also more prone to risky and aggressive driving and are involved in more crashes than their low-caffeine counterparts.
Researchers believe the link between caffeine and collisions could prove valuable, as the current advice in the Highway Code is for drivers who feel tired at the wheel to consume two caffeinated drinks and have a nap of at least 15 minutes.
But Dr Ashleigh Filtness of Loughborough University, who led the study, said it was important not to frighten people off drinking coffee if they are feeling tired at the wheel.
“There is plenty of evidence to show that caffeine is a good one-off countermeasure, but here we are looking at high use, a level more than the amount that 90% of the US population would consume,” said Filtness
Truckers are particularly vulnerable to fatigue because of their shift work and long hours at the wheel, and sleepiness doubles the risk of being involved in a crash, said Filtness. Caffeine can have a positive impact on crash risk, but when consumed in high amounts over long periods could potentially impair sleep, and increase tiredness and safety risk, he stressed.
The study, published in the journal Safety Science, was conducted using truck drivers in the US states of Illinois, Ohio, Kentucky, New Jersey, Virginia, Georgia, Texas and California.
Filtness said the complex relation between caffeine and truckers was important as the group had a higher than average consumption rate, compared to the rest of the population.