Directional Stability Under Braking (DSUB)

Overview

The Directional Stability Under Braking (DSUB) standard forms part of the Performance Based Standards (PBS) Scheme, administered by the National Heavy Vehicle Regulator (NHVR).

The revised DSUB standard modernises braking requirements for PBS vehicles and improves safety outcomes by increasing the use of advanced braking and stability technologies and introducing assurance measures to confirm these systems are powered, operational and fault-free when vehicles are in use.

Project background

At the May 2018 meeting of the former Transport and Infrastructure Council, Ministers endorsed the outcomes of the National Transport Commission’s PBS Marketplace Project. The project made four recommendations to strengthen the PBS Scheme, including a recommendation for the NHVR to complete a review of the standards.

In November 2019, Ministers endorsed the amendments to the DSUB standard proposed by the NHVR. The release of the revised DSUB standard represents the final stage of implementing these endorsed changes.

Changes to PBS Braking standard

From 1 July 2026, the DSUB standard is being updated to modernise braking requirements under the PBS scheme. These changes only apply to vehicles entering the PBS Scheme for the first time from 1 July 2026. These vehicles are:

  • Newly built vehicles
  • Existing in-service vehicles entering PBS for the first time.

The key changes for these vehicles will include:

  • Load Proportioning Valves (LPVs) will no longer be permitted
  • Minimum ABS is required on hauling units (including rigid trucks and buses)
  • Trailer EBS with roll stability function is required on trailers and dollies
  • Combinations must have a means to indicate that braking systems are braking systems are powered, operational and fault-free.

Vehicles issued with a PBS Vehicle Approval (VA) before 1 July 2026 are not affected by the revised standard and may continue to operate under their existing approvals. These vehicles are:

  • Grandfathered indefinitely
  • Not required to be upgraded to meet the revised DSUB requirements
  • Able to operate unchanged under their current PBS approvals.

Limited electrical requirements apply where pre-existing vehicles operate in mixed combinations with new DSUB-compliant vehicles (vehicles that entered PBS Scheme for the first time from 1 July 2026).

Industry webinar

To support industry readiness, the NHVR will hold an industry webinar. The webinar will provide:

  • Summary of the revised DSUB standard
  • Practical guidance on how the changes apply to different vehicle types and combinations
  • Opportunities for industry participants to ask questions.

An introductory webinar will be hosted by the NHVR. Recording will be available after the webinar and the session is open to anyone to attend:

Further information

The amended PBS Standards and Vehicle Assessment Rules will be published in due course, ahead of the commencement of the revised DSUB standard on 1 July 2026.

In the meantime, further information is available through the following resources:

If you have any questions or are seeking further information on the upcoming changes, please contact the PBS Enhancements Team at PBSReview@nhvr.gov.au.