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Unpacking the Heavy Vehicle National Law reform: expanded driver duty, mass, dimension and loading changes and more

Written by Nicolina Holmes

Amendments to the Heavy Vehicle National Law (HVNL) passed Parliament in November 2025 and are expected to commence in mid-2026.

 

The reform package, which includes the Heavy Vehicle National Law Amendment Act 2025 and amendments to several national regulations, brings significant changes aimed at improving the administration and efficiency of the heavy vehicle industry and the safety of heavy vehicle drivers and road users alike.

 

In our previous article, we explored the new accreditation framework and requirements for operators, drivers and others who work for heavy vehicle operations. In this article we look at the expanded driver duty, key changes to the Heavy Vehicle (Mass, Dimension and Loading) National Regulation (the MDL Regulation), the shift from the HVNL to National Regulations for some requirements and other important regulatory changes.

 

 

 

 

The expanded driver duty

 

Under the current legislation, drivers have a duty to not drive a fatigue-regulated heavy vehicle, which is over 12 tonnes (t), if they are impaired by fatigue.

 

Upcoming legislation changes will extend this duty to apply to all heavy vehicles over 4.5t and combine it with an additional duty to be ‘fit to drive’. Driving ‘fit’ considers apparent physical and mental fitness and the effect and concentration of drugs and alcohol on driving a vehicle or starting or stopping its engine, among other things.

 

Breach of this duty will incur an increased maximum penalty of $20,000, up from $6,000.

 

In addition, other requirements including s 26E (Prohibited requests and contracts), s 358 (Restriction on grant of work diary exemption (notice)) and s 540 (Requiring driver to stop working if impaired by fatigue) will be amended to reference the new requirement to be fit to drive.

 

 

 

 

 

Changes to the MDL Regulation

 

In an effort to boost productivity in the heavy vehicle industry, the following changes to the MDL Regulation (among others) have been proposed:

The increase of General Mass Limits (GML) to match limits under Concessional Mass Limits (CML)
  • The axle mass limits for tandem axle groups and tri-axle groups will increase to match their current CML equivalents, and the axle mass limits for quad-axle groups and groups of five or more axles will also increase. Bus axle group limits will be retained.
  • Tandem axle groups will have a maximum mass limit of 17t and tri-axle, quad-axle and groups of five or more axles will have a maximum mass limit of 21t.
  • Overall mass increase limits will be capped at 1t for heavy vehicles with a combined combination mass of less than 55t, and 2t for those with more than 55t.
  • Increased maximum masses for previously excluded vehicle types, such as truck and pig combinations and Class 1 vehicles, will also be granted.
  • The existing CMLs will be repealed.

The increase of vehicle length limits
  • The length limit for prime movers, semitrailers, rigid truck and pig trailer, rigid truck and dog trailer and rigid truck and tag trailer combinations will increase from 19m to 20m.
  • Trailers in a 20m combination with Gross Trailer Mass of over 10t will be required to be fitted and compliant with the latest braking technology (ADR 38/05 or later) and have the braking system powered by the towing vehicle.
  • The maximum S-dimension, and rear overhang limit, for 20m prime mover semi-trailer combinations will increase to 10.5m and 4.0m respectively.
  • The maximum distance from the front articulation point to the rear of the trailer will increase to 14.5m.
  • Prime movers and semi-trailers with an S-dimension of more than 9.5m will be required to be fitted with ADR 106-compliant side underrun protection.

The incorporation of Euro VI compliant prime movers into road train combinations
  • Road trains with a Euro VI compliant prime mover can access the 0.5t steer axle mass increase but will be restricted to a maximum of 7.0t.
  • Road trains with a Euro VI compliant prime mover will be required to have tyres fitted with a section width of at least 315mm.
  • Euro VI compliant prime movers with a twin steer axle group will also be able to access the 0.5t steer axle mass increase, with a maximum of 11.5t. This combination will also be required to have tyres fitted with a section width of 275mm and be fitted with a load-sharing suspension system.

The amendment of tow mass ratio and associated tag trailer conditions
  • The existing tow mass ratio requirement of 1:1 for a heavy vehicle towing a tag trailer will be replaced with a new tow mass ratio of 1:1.3.
  • A new requirement for the steer axle mass to be the greater of at least 20% of the truck’s Gross Vehicle Mass or the manufacturer’s minimum requirement will be introduced.

The transfer of requirements from the current HVNL

 Certain requirements relating to the definition of twin steer axle group, the display of warning signs and class 2 heavy vehicle authorisation (permits) and mass or dimension exemption permits will be moved from the current HVNL into the MDL Regulation.

 

 

 

 

 

 

The shift from HVNL to national regulation

 

Other prescriptive detail that is currently enforced under the HVNL will be transferred to the Heavy Vehicle (General) National Regulation, Heavy Vehicle (Fatigue Management) National Regulation and Heavy Vehicle (Vehicle Standards) National Regulation.

 

This shift aims to simplify the law and allow for the regulatory framework to better adapt to future technologies or industry needs. The transferred requirements relate to the following matters, among others –

 

Heavy Vehicle (General) National Regulation
  • What the National Heavy Vehicle Regulator (NHVR) must consider when assessing a Performance Based Standards (PBS) design approval application and PBS vehicle approval application.
  • The requirement for a driver to keep a copy of the PBS vehicle approval.
  • Provisions related to exemption (permits) and authorisation (permits) including amendment, suspension and cancellation, among other things.

Heavy Vehicle (Fatigue Management) National Regulation
  • How work and rest time is counted in 15-minute periods in written or electronic work diaries.
  • How information must be recorded in a work diary.
  • Provisions related to the form, application and issue of a written work diary.
  • Requirements relating to fatigue record keeping exemption (permits), work and rest hours exemption (permits) and work diary exemption (permits).

Heavy Vehicle (Vehicle Standards) National Regulation
  • The circumstances in which the requirement to comply with heavy vehicle standards does not apply.
  • The circumstances in which the NHVR can grant a vehicle standards exemption (notice).
  • Requirements for approval of heavy vehicle modification, or use of a modified heavy vehicle.
  • The offence for tampering with a heavy vehicle plate or label.
  • Requirements related to vehicle standards exemption (permits).

 

 

 

 

 

New codes of practice framework, strengthened enforcement powers and penalty changes

 

Other changes from this reform will update certain requirements relating to Codes of Practice (CoPs), powers and penalties. For example:

  • a new CoP framework will replace the existing industry CoP framework to support and guide Chain of Responsibility parties and drivers to meet their heavy vehicle duties and obligations. The NHVR will be responsible for issuing, amending and revoking CoPs.
  • new powers will be introduced for Responsible Ministers to issue directions to the NHVR relating to preventing and minimising serious public risk, acting in relation to alternative compliance accreditation, and investigating or providing advice or information.
  • the issue of an improvement notice concurrent with a prosecution for the same conduct will be allowed, provided the offence is deemed serious enough and there is sufficient evidence.
  • where suitable, authorised officers will be able to issue formal warnings instead of fines, and there will be a wider range of breaches for which formal warnings may be issued.
  • courts will be able to deliver alternative verdicts for primary duty offences.
  • there will be 50 penalty amount increases and 21 penalty amount decreases, as well as consolidation of several offences. (For a full list of these, email info@enviroessentials.com.au).

 

 

 

 

 

 

 

Keeping your compliance on track with Environment Essentials

 

These amendments are anticipated to become law in the middle of 2026 and will be summarised and incorporated into our health and safety online directory, SafetyLaw, after they have commenced.

 

These detailed and easy-to-read summaries can be integrated into your processes, policies and procedures, used for internal compliance evaluations or as an aid to cultivate understanding and compliance among employees.

 

Our complimentary news service, HSE Bulletin, will also notify you of additional developments leading up to the commencement date.

 

If you are an Environment Essentials subscriber and would like to add SafetyLaw to your cache of products, please contact your Account Manager or our client services team.

 

If you are not an Environment Essentials subscriber but would like to stay on top of the heavy vehicle reform and identify, understand and integrate your heavy vehicle requirements, then sign up for a free trial today or get in touch with our sales team.

 

 

 

 

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