Performance Based Standards (PBS)

Performance Based Standards (PBS)Performance Based Standards (PBS) offers potential for heavy vehicle operators to achieve higher productivity and safety through innovative vehicle design.  PBS focuses on how well a vehicle behaves on the road, through a set of safety and infrastructure protection standards, rather than assessing a vehicle based on prescriptive limits.

If a heavy vehicle operator wishes to introduce an innovative vehicle that is outside the scope of any existing Main Roads permit products, the operator is encouraged to seek approval via the PBS Scheme.

Once approval has been obtained via the PBS Scheme, we will issue a permit to allow the innovative vehicle to operate within Western Australia.


WA PBS Process

The WA PBS process may be followed if an operator only intends to use the PBS vehicle in WA. If approval is sought to operate in other jurisdictions, the below National PBS Process should be followed.

We are committed to supporting the use of innovative PBS vehicle combinations that result in safer and higher productivity vehicles on WA roads. If you would like a vehicle approved through the WA PBS Scheme, you should refer to the following document that has been developed to provide an overview of the WA PBS Scheme application and approval process.


Transport operators should obtain an "in-principle" approval from us in the first instance to ensure their proposed combination and required level of access is achievable. Simply complete and submit the below PBS Application Form.  Further information in relation to the different access levels and principles can be found in the following document.


Once the initial proposal has been reviewed and an "in-principle" approval has been issued confirming the proposed vehicle combination and transport task is achievable on the requested routes, the applicant will then need to engage an approved PBS assessor  to have the vehicle assessed in accordance with the following rules and standards.


The completed PBS assessment will then need to be forwarded to us. If the proposed operation is WA specific, the PBS assessment does not need to be submitted to the NHVR Review Panel, it can simply be forwarded directly to us.

A full review of the PBS assessment is undertaken to ensure all required standards for the design vehicle and the requested access are met. If all standards are met, a PBS Design Approval will be issued.

When the vehicle has been built, the applicant will then need to engage an approved PBS certifier to certify the vehicle has been built as per the design specifications. The certification documentation needs to be forwarded to us as the final step in the application process, along with the below PBS Application Form.

The PBS permit is then issued for the vehicle combination, which will include the approved routes and specific operating conditions.

For further information about the PBS Scheme in WA please contact or 138 486.


PBS Application Form

The following application form is to be used when apply for an "in-principle" approval and a PBS permit.


PBS Audit Framework

Vehicle combinations approved under the PBS scheme are assessed, certified and approved based on a specific vehicle design.  To ensure PBS vehicles continue to perform to a high standard, it is essential the vehicles are maintained to their defined specifications, i.e. components are not altered without approval and the vehicle is maintained in good working order. 

The PBS Audit Framework provides the framework Main Roads use to conduct audits on vehicles approved under the PBS scheme.  These audits ensure the vehicles are being maintained to their defined specifications and as such will continue to meet the safety standard that formed the basis of their initial approval.  


60 metre Road Train Signage

Due to Level 4B PBS vehicles (up to 60 metres in length) being the longest road trains approved to operate on the public road network, additional signage is considered necessary to ensure other road users are aware extra caution is needed when overtaking. Refer to the following documents for signage specifications.

PBS Minimum Axle Spacing Requirements

PBS vehicles that do not meet all of the infrastructure related standards may still be approved under the WA PBS Scheme, provided they comply with the minimum axle spacing requirements outlined in the following table:

​Adjacent Axle Group​Minimum Outer to Outer Axle Spacing​Minimum Inner to Inner Axle Spacing​Maximum Mass Permitted
​Tri to Tri Axle​9.2 Metres3.4 Metres23.5t on Tri Groups
​Tri to Quad Axle Groups10 Metres​3.4 Metres20t on Tri Groups and 24t on Quad Groups
​Tri to Quad Axle Groups​11 Metres​3.4 Metres23.5t on Tri Groups and 28.5t on Quad Groups
​Quad to Qaud Axle Groups12 Metres​3.4 Metres​27t on Quad Groups
​Quad to Quad Axle Groups12.5 Metres3.4 Metres28.5t on Quad Groups
Image: PBS Axle Spacing.PNG
National PBS Process

The National Heavy Vehicle Regulator (NHVR) administers the National PBS Scheme assessing and approving PBS designs on advice from the PBS Review Panel.

You are still required to negotiate road access separately through State or Territory road authorities. As such, it is strongly recommended you contact us prior to engaging a PBS Assessor to obtain "in-principle approval.

Once a PBS approval is granted by the NHVR, a permit is still required from us to operate the vehicle within Western Australia.


Modified: 06 Nov 2017