Les Brusza, now with the National Heavy Vehicle Regulator, as Chief Engineer, but earlier working as an engineer based in Brisbane for Queensland Transport (now TMR) has been at the forefront of the development of Performance Based Standards (PBS) and is now involved in extending PBS vehicles.
“We also see an increased number of larger combinations, which are longer than the conventional length limits,” said Les, speaking earlier this year.
“In Victoria and Tasmania, we see an increased number of A-doubles, which are longer than 30m. Then we have split axle groups, which is another way of increasing productivity, and then some other new technologies.”
New ideas about design are emerging regularly. There are now A-doubles with split axles, and some now include another extra axle group. One combination, able to carry carry 97 tonnes, is only at B-double length. Comparing this combination versus the 68 tonnes GCM for a B-double demonstrates a huge increase in terms of GCM.
The longer B-doubles and the introduction of quad axle groups in different combinations is also a growing trend. These innovations are proving to be very efficient, not just for volume based products, but also for for heavier loads.
“What’s interesting now is that we have a PBS combination in almost all of the different areas,” said Les.
“There is a PBS version for all the different freight types, even concrete mixers, trucks carrying tyres, logging vehicles or containers. That means the PBS scheme is providing a framework for operators to optimise a combination for a particular freight task.
“The number of combinations with two axle groups or split axles is growing. The idea behind this is to increase the payload on those vehicles. Unfortunately, in this country, we have haven’t had any significant increase in axle loads, basically, since 2001, when the Higher Mass Limits system was introduced.”
This means the only method of improving the productivity of vehicles is for operators to begin putting more axles under the vehicle or more axle groups. The mega van, for instance, can carry the load of a B-double, and it’s a semi.
“Just think about it in terms of how you operate this vehicle, in terms of the loading issues and maintenance,” said Les.
“Obviously, the problem with this is that it’s completely new, we don’t have rules, nationally accepted rules, which would give us guidelines around how these vehicles should be designed, and what are the requirements. So at the NHVR we had to develop those technical requirements.
“Even if you just think about a definition of a vehicle, we are still having issues because the definition in the ADR says that a semi has a trailer with with one axle group towards the rear, so what happens if you have a semi trailer with two axle groups?
“We are using technology on a PBS combination which is a 42m long, B-triple for instance, using steering axles to improve the the low speed performance of the vehicle. So you’ve got this 42m long B triple, which can comply with Level 3 PBS standards.”
Time and again PBS demonstrates it improves the performance significantly, enabling operators to optimise combinations.
The NHVR have been researching, with the Truck Industry Council, super single tyres, in the belief that these tyres can make a considerable contribution to improved performance and productivity. They are widely used in North America and Europe, but, currently, Australian and state regulations mean they are restricted in terms of how much load they can carry.
Research funded by the Heavy Vehicle Safety Initiative has demonstrated that super singles can improve the stability performance of a vehicle enabling them to withstand rollover more effectively. PBS is the only framework inside which the NHVR can approve the use of super singles.
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