Judging by the layout of a chart released by the National Heavy Vehicle Regulator, trucking operators in Australia are going to be spoilt for choice by PBS. There’s plenty of ideas for the industry to get their teeth into and the combinations illustrated may inspire some to come up with further innovations on our roads.
The NHVR has released a new PBS Vehicle Configurations chart showing 32 common combinations approved under the Performance Based Standards scheme. The range of trucks is wide and gives us a picture of the way the development of trucks and combinations is heading.
The chart also tells us the story of how PBS has developed as it has rolled out over time. It was a very shaky start to a scheme which many had high hopes for. The early adopters spent months with trucks or trailers sat in yards while they battled with road managers over the right to access the roads for which they had been built. This problem can still occur today, but the incidence is decreasing.
The gulf in understanding between the owners and designers of the trucks and those who had the final say on allowing the trucks to run was massive. A lack of understanding and expertise was an ongoing issue among road managers, especially those in more remote local authority areas.
Over time the strong lobbying by operators in different areas and an effective education program led by the NHVR, has seen a better understanding grow among the road engineers signing off on these trucks. This is now at a point where some of the routes which were contentious as the first combinations sought access are becoming as-of-right routes.
One example is this week’s publication of a notice by the NHVR allowing A-doubles access to the route between Brisbane Port and Toowoomba without the need to run through the PBS process. This applies to GML and CML, but those wanting the extra few tonnes available at HML will still have to jump through the PBS hoops.
The chart of combinations gives us a snapshot of the scheme as it now stands. It also shows us how the PBS trucks have moved prescriptive rules around trucks. There are seven combinations with twin steer trucks, something which would not have been envisaged before PBS changes came though.
PBS has proved to be a tool which demonstrates the twin steer should get a higher mass allowance and that is slowly coming to fruition. However, the authorities still hang on to the requirement for a load sharing suspension. This is required nowhere else in the world and truck technology development for just one market can be expensive. As a result the take up of twin steer trucks is limited, despite them being a much more stable, and therefore safer, truck on the road.
Then there’s the unusual AB-double combination. By using a much wider axle spread on a dolly, it becomes a virtual lead trailer without a load carrying capacity. As a result of the innovative design, this combination can run at 59.5 tonnes on just 7 axles. It is particularly manoeuvrable with a steer axle on the dolly and has found a home in some milk tanker fleets.
This kind of highly productive innovative design would never have got up in the old prescriptive system, but it is functioning well under the PBS regime.
Also functioning well is the ever growing big tipper and dog community. The combination had a bad rap for many years, but surprised many engineers by coming through the computer simulation testing as a stable set-up. By simply extending drawbars and including safety technology the tipper and dog has transformed from an unwanted necessity to a high productivity performer with trailers having up to six axles.