Truckies driving more than three hours a night are susceptible to errors equivalent to having a blood alcohol level of 0.08, according to Australia's biggest study of heavy vehicle crashes.
The four-year study by Monash University Accident Research Centre and Curtin University analysed truck accidents in WA and NSW between 2008 and 2011.
It also looked at the driving schedules, payment rates and sleep patterns of drivers involved in recent crashes.
The results, published recently in the American Journal of Epidemiology, show long-distance truckers are almost three times more likely to crash between midnight and dawn.
Having an articulated truck with an empty load also doubled the chances of a crash.
Research leader Mark Stevenson said this might be attributed to speed associated with time restrictions imposed to pick up a new load and/or finish a shift.
In the centre's latest The Big Impact newsletter, Professor Stevenson said the results pointed to the need to change schedules and introduce more frequent breaks to reduce "challenges associated with monotonous driving".
Research interviews were done with 530 drivers who were in a recent crash and 517 who were not.
The drivers, all aged over 40, also wore a nasal-flow monitor to measure sleepiness.
Based on the interviews, which included questions about sleep, driving and lifestyle, the researchers found:
· Truckies driving for more than eight hours were twice as likely to be in a crash.
· Seven out of 10 drivers who crashed had used caffeinated drinks to stay awake.
· Two of five drivers involved in crashes had less than 10 years experience.
The research also found a link between crash rates and safety devices attached to trucks.
For example, for trucks not equipped with anti-lock braking systems, the risk of a crash increased 50 per cent.
And the lack of cruise control was tied to a 64 per higher risk.