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NHVR Mass &
Dimension Limits

This must be considered if you are an owner/operator of a freight business or company that runs high-productivity vehicles such as B-doubles and Higher Mass Limit (HML) heavy vehicles.

It’s crucial that you ensure your operations

Meet the NHVR’s requirements around heavy vehicle mass and dimension limits

This applies for each heavy vehicle you have registered to operate on Australia’s national road network.

The NHVR outlines the requirements for heavy vehicles in the Heavy Vehicle (Mass, Dimension and Loading) National Regulation 2013 – which includes the conditions for operating both general and restricted access vehicles relating to axel mass and configuration, as well as the general, concessional and higher mass limits for heavy vehicles.

General mass limits

As per NHVR regulations, General Mass Limits (GML) apply to all heavy vehicles and heavy vehicle combinations that operate on Australian roads.

GML describes the mass limits permitted for all types of heavy vehicle axle groups, unless you have an exemption under Heavy Vehicle National Law (HVNL).

The NHVR Heavy Vehicle Mass and Dimension Limits Fact Sheet (HVMDL) covers the prescribed dimensions for the width, height and length of heavy vehicles such as rigid trucks, semi trailers and dog trailers, as well as the correct length and articulation point for trailers, and rear overhang requirements, and the axle mass limit for Australian heavy vehicles.

The HVMDL Fact Sheet also outlines dimensions used in the heavy vehicle industry relating to specific trailer types including livestock carriers (for cattle, horses, pigs or sheep), refrigerated vans, and car carriers, and provides detailed comparison tables for axle mass limits.

Higher mass limits

Higher Mass Limits (HML) provide a significant increase in the productivity of road freight transport vehicles – increasing overall efficiency and reducing the number of vehicles required to transport freight in any given operation.

In some circumstances, you may be eligible to operate heavy vehicles with Higher Mass Limits (HML) – which allow for some types of heavy vehicles to access additional mass entitlements. This is permitted only if vehicles are fitted with certified road-friendly suspension that reduce the impact of laden axles on road pavements and bridge structures, and are on an authorised HML route (permits apply).

Higher Mass Limits (HML) allow particular heavy vehicles to access additional mass entitlements providing:

  • Operators of vehicles or combinations running HML on tri-axle groups are accredited under the Mass Management Module of the National Heavy Vehicle Accreditation Scheme (NHVAS), with an accreditation label fitted to the hauling unit
  • Vehicles are fitted with certified road friendly suspension
  • Vehicles are on an authorised HML route

The maximum mass (tonnes) per axle group permitted under HML (compared to GML – in brackets) includes:

  • Tandem axle group – 17t (16.5t)
  • Tri-axle group – 22.5t (20t)
  • Single drive axles on buses – 10t (9t)
  • Six-tyre tandem axle groups – 14t (13t)

Eligible operators can apply for an HML permit via the NHVR.

When operating a HML in QLD and NSW, participation in the Intelligence Access Program (IAP) is required. JMH can develop and implement the Mass Management Accreditation for operators.

Dimension limits

The prescribed heavy vehicle dimension limits for Australian heavy vehicles are outlined in full on the NHVR website, and include:

  • Width limit of 2.5 metres – excluding rear vision mirrors, signalling devices, side-mounted lamps and reflectors, anti-skid devices mounted on wheels, or permanently fixed webbing-assembly-type devices.
  • Height limit of 4.3 metres – unless the vehicle is designed to carry cattle, pigs or sheep (4.6 meters), is built with two decks to carry vehicles (4.6 meters) or is a double decker bus (4.4 meters).
  • Length limit of 19 meters for a combination other than a B-double, road train or a car carrier.

Limits relating to specific trailer types including semitrailers, agricultural vehicles, livestock carriers, dog trailers, pig trailers, refrigerated vans or car carriers vary, and also have requirements about the distance from the front articulation point to the rear overhang line, and the distance from the front articulation point to the rear, as well as maximum forward projection requirements.

Common heavy freight vehicle configurations

The NHVR’s Common Heavy Freight Vehicle Configurations Chart shows some of the most common rigid trucks, semitrailer combinations, rigid truck and trailer combinations, double-B combinations, and type 1 and 2 road trains (class 2) currently in operation across Australia. While it is not a definitive list – and you may be eligible to operate heavier or larger vehicles in certain circumstances – it is a good guide for mass and dimension limits for common Australian heavy vehicle types.

The configuration table shows the maximum length permitted for each of the classes of heavy vehicle, as well as the maximum regulatory mass (in tonnes) under General Mass Limits (GML), Concessional Mass Limits (CML) and Higher Mass Limits (HML). These mass and length limits are based on the Heavy Vehicle (Mass, Dimension and Loading) National Regulation.

For more information or advice about heavy vehicle mass and dimension limits, please contact Jodie Hamilton on 0427 860 226 or email

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