The findings run up against the realities of the
global truck freight industry, where irregular schedules and
incentive-based payment systems enticing drivers to the next load
are still common, said Mark Stevenson. He led the study from the
Monash University Accident Research Centre in Melbourne.
"If companies are setting schedules that require drivers to compete
with their natural circadian rhythm, then that places them at a
higher risk for a crash," Stevenson told Reuters Health.
He and his colleagues recruited a nearly all-male group of 530
truckers with a recent non-fatal road crash confirmed by a police
report. They also tracked down 517 drivers with no crash reports to
serve as a comparison group.
The truckers were recruited at rest stops along heavily traveled
truck routes in New South Wales and Western Australia. Drivers in
both groups answered questions related to sleep, driving and
lifestyle habits during a 40-minute interview. They also wore a
sleep monitor for one night. Participants were in their mid-40s, on
Drivers with less experience were three times more likely to be
involved in a non-fatal accident and those traveling with an empty
load were more than twice as likely to crash. Truckers who had been
driving for less than eight hours had about half the odds of
crashing as those further into their trip.
The new study confirms a link between late-night driving and crash
risk, but also adds plenty of detail on other risk factors, said Dr.
Barbara Phillips, from the University of Kentucky College of
Medicine in Lexington.
For instance, the researchers found not having anti-lock braking
systems on a truck was tied to a 50 percent higher risk of crashing.
Lack of cruise control was tied to a 61 percent higher risk.
"That is news," said Phillips, who has studied long-haul drivers but
was not involved in the current study.
"Some drivers prefer not to use cruise control because they think
they have limited control of the vehicle," said Stevenson.
"But once cruise control is activated, it does assist the driver in
maintaining a constant, safe speed," he said.
Truckers who drank caffeinated beverages had one third the odds of
crashing as those who didn't, the researchers report in the American
Journal of Epidemiology.
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Contrary to previous research, Stevenson and his
team found that sleep apnea, a sleep disorder, was not tied to crash
risk. About 19 percent of drivers who had been in a crash and 16
percent of comparison drivers were determined to have "likely
"With sleep apnea, you are getting very poor quality sleep. So some
of the drivers are already starting work with a sleep deficit,"
But Phillips said the apnea monitors given to truckers in the study
did not measure certain parameters which have been linked to an
increased risk of accidents.
"Based on the methods
used here, and the exclusion of crashes with deaths or injuries, I
do not think it's a safe conclusion to draw," Phillips said of the
sleep apnea finding.
The type of study design used by the researchers, called a
"case-control," can be useful for studying small groups of people.
But, as they point out, the comparison group may not have the exact
same characteristics as drivers who had crashed.
Both Stevenson and Phillips agreed that truck drivers and car
drivers will inevitably drive while sleep-deprived.
The current research offers some advice, Phillips said.
"One, drivers should drink caffeine. Two, they can use cruise
control if they have it. And, three, they need to take frequent
breaks," she said.
American Journal of Epidemiology, online Dec. 18, 2013.
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