In a paper presented to an international conference in Berlin this week, two Monash University researchers studied the way truck drivers’ compensation related to fatigue behind the wheel.

About 350 drivers in NSW and WA were surveyed over two years, in one of the largest studies of driver behaviour and compensation undertaken in Australia.

The researchers found that drivers who were paid a “piece rate” – or on a per-kilometre or per-trip basis – drove for an average of up to 5.3 hours between breaks. This was an hour longer than those paid a salary or hourly wage.

“Anything above four hours is really starting to get into higher-risk territory,” Jason Thompson, a co-author of the study and research fellow at the Monash Accident Research Centre, said.

More than 70 per cent of drivers surveyed were paid on an incentive, piece rate basis, a figure that rose even higher among NSW drivers.

Drivers paid on an incentive basis were also more likely to admit to using amphetamines behind the wheel: nearly 10 per cent of those who were paid per trip did so, compared with 2 per cent for those paid per kilometre and none on weekly or hourly wages.

“They reported all the signs of trying to fight sleepiness,” Mr Thomson said. “The fact that people are trying to fight fatigue and some people are going to lose that fight is concerning.”

Drivers on incentive payments reported slightly less sleepiness and fatigue. They also drove up to 150 kilometres a day more on average and were more likely to have slept in their truck the night before.

The new research comes as the federal government considers the future of the Gillard government’s Road Safety Remuneration Tribunal, a national body with the power to set pay and conditions for truck drivers.

A review into the body was handed to Employment Minister Eric Abetz but is yet to be released.

The minister told federal parliament there was no evidence to justify claims of a link between remuneration and safety but declined to comment for this story.

Transport Workers’ Union assistant state secretary Michael Aird said the study’s findings proved a link between pressure on drivers and safety.

“There needs to be safe rates for truck drivers if lives are to be saved,” Mr Aird said. “The Prime Minister needs to decide if he’ll back truck drivers and the community and support the RSRT’s efforts to deal with the systemic issues causing over 300 deaths a year.”

National Road Transport Association chief executive Chris Melham said he backed the abolition of the national regulator.

“Despite an increase in the number of heavy vehicles on our roads and the distances travelled, accidents involving heavy vehicles are continuing to reduce at an increased rate,” he said.

Heavy trucks make up about 3 per cent of road traffic but more than 15 per cent of fatalities, according to the federal Department of Transport.