Fire and mechanical failure now cause more serious truck crashes on Australian roads than driver fatigue, a report by the nation's leading insurer of heavy vehicles has found.
The finding raises troubling questions about whether the standard of truck maintenance has slipped to dangerously low levels just as the number of heavy vehicles on the roads has soared, the report states.
The National Truck Accident Research Centre's 2013 major accident investigation report found fire caused 12.1 per cent of major truck crashes in 2011, compared to 11.9 per cent that were caused by fatigue. Mechanical failure caused a further 5 per cent of crashes.
The centre's previous report, from 2011, found fatigue was to blame for almost twice as many serious truck crashes as fire. Speeding remains the greatest problem, responsible for one in four truck crashes.
Report author Owen Driscoll said it was clear fire was causing many more truck crashes than when the first biennial study was done in 2003. ''Such fire losses originate from failed wheel bearings, brakes, engine, cabin electrical wiring and trailer refrigeration equipment,'' Mr Driscoll wrote. ''It naturally [raises] the question of whether the standard of quality and regular equipment maintenance has become less rigorous.''
Two people were killed in Sydney last Tuesday when a petrol tanker ran out of control, caught fire and exploded.
The truck's owner, Cootes Transport, has since had its fleet audited by VicRoads, which found defects on 114 out of 128 vehicles.
Faults identified included oil and air leaks, brake and suspension defects, and structural integrity problems. Forty-seven of the defective vehicles have been grounded, with others to undergo repairs before returning to the road.
Cootes announced on Monday that it had withdrawn from Australia's voluntary accreditation scheme for heavy vehicle maintenance management, and would instead subject its fleet to vehicle inspections by state authorities.
The maintenance standards of Australia's truck operators are policed through a combination of voluntary adherence to a national accreditation scheme and routine state checks. But trucking industry consultant Rob di Cristoforo said state departments lacked the resources to complete a high number of inspections, and ''bad apples'' sometimes operated undetected.
''There aren't the resources there to check trucks frequently enough to catch all of them out straight away and that's a big problem,'' Mr di Cristoforo said.
Neil Chambers, chief executive of the Victorian Transport Association, said the industry group urged operators to join the national accreditation scheme. In total, 1772 Victorian companies are scheme participants.
''You've got more trucks and trailers on the road, that's the start, and they're running longer distances than they ever have before, so there's always a component of an additional number of vehicles out there leading to a rise in accident rates,'' Mr Chambers said.
There was a 43 per cent increase in freight volumes between 2009 and 2011 and a ''directly proportional'' spike in major crashes among operators insured with National Transport Insurance, the biggest truck insurer and Truck Accident Research Centre found.