Wellington, May 27 NZPA - Statistics presented to a Parliamentary transport select committee today show a continuing downward trend in the involvement of heavy trucks in fatal crashes, but improvements to serious injury crash statistics are less pronounced.

Ministry of Transport figures showed the number of heavy trucks (3.5 tonne or more of gross laden weight) on New Zealand roads increased 28 percent to 113,073 between 2000 and 2009, while between 1995 and 2009 the number of kilometres travelled by heavy trucks increased 51 percent to 2.45 billion km, according to road user charge purchase details.

The number of fatal crashes involving a truck declined steadily from 107 in 1995 to 51 in 2009, and comparable figures where the truck was at fault reduced from 35 to 15.

When it came to serious injury crash figures the reduction was less marked and showed more of a flat line.

The ministry's acting general manager of safety, Leo Mortimer, said the statistics were positive.

"I think the importance here is that across all government areas, whether it's Labour or ACC, the fatalities are going in the right direction."

He said getting the injuries and serious injuries caused by crashes involving trucks to trend downwards was more difficult, but putting those figures into context with the increased milage travelled indicated a positive trend.

Recently introduced safety measures likely to further improve crash statistics included a requirement enacted in 2007 for advanced braking systems in new trucks entering the fleet (braking issues contribute to the highest percentage of crashes), along with updated logbook and rest requirements and recent work on addressing driver fatigue, including the use of rumble strips, barriers, rest areas and focused education.

New drug testing powers for police was also seen as a positive initiative for transport safety in general, and further technology initiatives, including the mandatory use of vehicle "under-run" barriers on trucks and stability control were being investigated.

The ministry predicted it would take another 15 years before the entire trucking fleet was equipped with the advanced brake technology.

The latest change to the heavy transport sector involved a controversial rule enacted this month allowing for heavier loads on some vehicles travelling on specific routes.

Ministry officials said it would make the road transport sector more efficient, with fewer trucks carrying more freight, and had the "potential to improve road safety".

Opponents say it will lead to greater carnage, along with greater damage to roading infrastructure.