PBS Vehicle Approval explained - Mass tables, PBS Level and bridge compliance

Mass tables

The mass table listed on the PBS Vehicle Approval (VA) contains:

  • Level of PBS approval, i.e. Level 2
  • Mass limits under different mass schemes, including total combination mass and axle group masses
  • Bridge assessment requirement. 
Example of a PBS VA mass table
Figure 1: Example of a PBS VA mass table

All masses specified in the mass table must not be exceeded.

These figures in the table are the maximum masses at which the combination on the VA complies with PBS standards. Actual masses a vehicle operates at may be lower than the maximum specified in the mass table.

Individual axle group masses may not add up to the total combination mass.

Please note that the masses of individual axle groups may not necessarily sum up to equal the total combination mass limit. This is intentional, allowing for individual axle groups to be loaded to more generous amounts while limiting the overall combination mass.

PBS Level

PBS vehicles are classified into one of four levels – PBS Levels 1 to 4. A vehicle that is approved at a particular level may be eligible to operate on the road network of the same classification level or higher.

The suitability of operation on road networks is subject to road manager approval (access permit) or compliance with a Notice.

Mass limits definitions

  • GML – General Mass Limit
  • CML – Concessional Mass Limit
  • HML – Higher Mass Limit
  • QML – Quad-axle Mass Limit (used in place of CML/HML where a combination includes quad-axle groups).

To operate at these limits, specific operating conditions apply, which are outlined in the Operating Conditions section on the PBS Vehicle Approval.

Axle group masses

The axle group mass is the maximum mass to which each axle group can be loaded; these limits must not be exceeded.

For steer axles operating at 6.5t, 7.0t or 7.1t, special operating conditions apply, as indicated in the 'Operating Conditions' section on the PBS Vehicle Approval.

Bridge compliance

To ensure continued infrastructure protection, all PBS vehicles are assessed against the PBS bridge formulae.

Please note that the level of bridge assessment specified on the VA is indicative only; the actual bridge assessment requirement will be determined by the responsible road manager during the access permit application process.

There are three types of bridge assessment requirements specified on a VA:

Tier 1 – bridge formulae using the same principle as 'Axle Tables' in Schedule 1 of the Heavy Vehicle (Mass, Dimension and Loading) National Regulation (MDL), which limits the mass between any extreme axles of any two axle groups.

Combinations that fail to comply with the Tier 1 bridge formulae require a Tier 2 or 3 bridge assessment.

Tier 2 – is a type of bridge assessment also known as Maximum Effect Relative to Reference Vehicle (MERRV).

The assessment is used to demonstrate that the maximum bridge effects of a subject vehicle do not exceed those caused by a reference vehicle. This type of assessment must be undertaken by a qualified engineer.

Tier 3 - requires a detailed individual bridge assessment using the actual bridge’s data. This type of bridge assessment is organised by the Road Manager and may be outsourced to a qualified engineer. This type of bridge assessment may attract significant cost and take an extended period of time to complete.

Some VAs specify a combination of bridge assessment types, i.e. ‘Tier 2/3’, meaning that the most appropriate type of bridge assessment is to be determined by the responsible road manager during the access permit application process.

Euro VI mass transfer

Euro VI vehicles can be approved through the PBS Scheme. The mass table on the VA will show the applicable steer masses if the combination has been approved for Euro VI masses.

In some cases, Euro VI approval allows for a mass transfer allowance. The mass transfer allowance allows for up to 0.5t be transferred between the steer and drive axle. This also needs to be approved and if it is, it will be listed within the VA mass table.

Example of a PBS VA mass table WITH Euro VI Mass Transfer Allowed
Figure 2: Example of a PBS VA mass table with Euro VI Mass Transfer Allowed
Example of a PBS VA mass table WITHOUT Euro VI Mass Transfer Allowed
Figure 3: Example of a PBS VA mass table without Euro VI Mass Transfer Allowed

To operate with the Euro VI Mass Transfer, specific operating conditions apply, which are outlined in the 'Operating Conditions' section on the PBS Vehicle Approval.

NHVR PBS contacts

  • For questions about PBS Design Approvals, contact our PBS Designs team at pbsdesigns@nhvr.gov.au
  • For questions about PBS Vehicle Approvals, contact our PBS Vehicle Approvals team at pbs@nhvr.gov.au
  • For questions about access and permits to operate your PBS vehicle on the road, contact us.
www.nhvr.gov.au