Heavy vehicle owners may be neglecting truck maintenance, according to National Transport Insurance (NTI).

The number of “non-impact” fires in trucks has grown in the past two years, as have trucking accidents in resource-rich states, the NTI’s Major Accident Investigation Report shows.

There has been a 42% reduction in truck accidents since 2003, according to the study, which is conducted every two years.

But this year’s report, which covers truck crashes that occurred in 2011, highlights some worrying trends.

Of 461 major crashes with a combined cost of $54.7 million, speed was the most common cause at 25.5%, down from 31.8% two years ago.

However, there has been an alarming rise in the number of non-impact fires, according to report author and NTI Industry Relations National Manager Owen Driscoll.

He says it raises questions about the quality and frequency of maintenance as trucking equipment grows increasingly sophisticated.

“The fire issue is definitely a combination of both problems and it’s definitely a trend,” he told insuranceNEWS.com.au.

“These machines are now essentially moving computers. Where we once had six metres of wiring, now we have 60. As trucks become increasingly complex, we need to ensure the ongoing maintenance of these vehicles is not ignored.”

More than 12% of major incidents in the past two years were caused by fire, with an average loss of $170,129 – 43% higher than the average accident.

Of those, more than 60% were engine and cabin fires, mostly caused by faulty wheel bearings, brakes, cabin wiring and trailer refrigeration equipment.

“This highlights the importance of rigorous and consistent maintenance in the day-to-day processes of all transport operations,” Mr Driscoll said. “To improve safety on our roads, we must first ensure the vehicles on our roads are safe.”

The National Heavy Vehicle Regulator was created in January to monitor trucks of more than 4.5 tonnes.

However, each state must pass the Heavy Vehicle National Law Amendment Bill 2012 for the body to have real power. Queensland did so last month.

The NTI report says the number of trucking accidents in Queensland and WA has risen.

Queensland accounts for about 18% of the nation’s total trucking freight, but nearly 30% of all accidents. About 15% of freight is in WA, yet the state accounts for 17.8% of total accidents.

B-doubles are the safest heavy vehicles, accounting for 23.6% of crashes while assuming 45% of the workload in total loaded tonnes, the study finds.

Midnight to 6am remains the riskiest time for a crash, at 52% of all incidents, while 68% of accidents happen within 250km of the truck’s departure point.