Long-distance lorry drivers who drink coffee have fewer road traffic accidents, research suggests.

Australian investigators say they found the link while comparing 530 heavy goods vehicle drivers who had recently been in a crash with 517 who had not.

Coffee and other beverages containing the stimulant caffeine cut crash risk, probably because they boost alertness, the British Medical Journal reported.

Road safety experts stressed caffeine was no substitute for sleep.

In the study, more than a third said they drank caffeinated beverages and half of these said they did so in order to stay awake.

The drivers who consumed caffeine to keep them from nodding off behind the wheel were 63% less likely to crash than drivers who had no caffeine.

This was after adjusting for factors such as age, sleep patterns, kilometres driven, breaks taken and night-driving schedules.