The information on this page is also in the National heavy vehicle mass and dimension limits fact sheet (PDF, 1.4MB).
General Mass Limits
General Mass Limits (GML) apply to all heavy vehicles. The GML state the allowable mass for all types of heavy vehicle axle groups unless the vehicle is operating under an accreditation or an exemption under the Heavy Vehicle National Law (HVNL).
- General Mass Limits fact sheet (PDF, 564KB) - Detailed information on axle mass limits and axle spacing.
1-Tonne Tri-Axle Mass Transfer Allowance (1TMTA)
The 1TMTA provides heavy vehicle operators with flexibility in loading certain heavy vehicle combinations. The 1TMTA allows increased mass on tri-axle groups so that they may be loaded by up to 1 tonne (t) above the normal tri-axle group 20t General Mass Limit (GML) provided any additional mass loaded onto each tri-axle group is offset onto other non-steer axle or axle groups.
Measurement adjustment
Applying an agreed adjustment to account for possible variations allows the measurement to be based on the highest degree of accuracy achievable at any time and provides fairness to the outcome of the measurement process. The measurement adjustment process also provides fairness to industry and legal certainty in considering enforcement action.
- Measurement adjustment is a nationally agreed process that only applies when an authorised officer measures or weighs a heavy vehicle for compliance and enforcement purposes
Prescribed dimensions
The prescribed dimension requirements for heavy vehicles are set out under the Heavy Vehicle (Mass, Dimension and Loading) National Regulation.
- General Dimension Requirements fact sheet (PDF, 1MB) - National heavy vehicle general dimension requirements.
Width
The width limit for vehicles is 2.5 metres, excluding:
- rear vision mirrors, signalling devices and side-mounted lamps and reflectors
- anti-skid devices mounted on wheels, central tyre inflation systems, tyre pressure gauges
- permanently fixed webbing-assembly-type devices, such as curtain-side devices, provided that the maximum distance measured across the body including any part of the devices does not exceed 2.55 metres.
Height
The height limit for heavy vehicles is 4.3 metres unless it is a:
- vehicle built to carry cattle, horses, pigs or sheep - 4.6 metres
- vehicle built with at least 2 decks for carrying vehicles - 4.6 metres
- double-decker bus - 4.4 metres
Length
The length of a heavy vehicle is:
- for a combination other than a B-double, road train or a car carrier—19 metres
- for a B-double—25 metres
- for a road train—53.5 metres
- for a car carrier —25 metres
- for an articulated bus—18 metres
- for a bus other than an articulated bus—14.5 metres
- for another vehicle—12.5 metres
Trailers - On a semi-trailer or dog trailer the distance from the front articulation point to the rear over hang line must not be more than 9.5 metres and the distance from the front articulation point to the rear of the trailer must not be more than 12.3 metres. The maximum forward projection of a semi-trailer, or anything attached to a semi-trailer must not protrude beyond a 1.9-metre arc from the towing pivot pin (King pin). The articulation point to the rear of a semitrailer may be up to 13.2 metres if the trailer has a distance of not more than 9.5 metres from the front articulation point to the rear overhang line, does not operate in a B-double or road train combination and otherwise complies dimensionally.
Refrigerated van trailers - The distance from the articulation point to the rear of a semi-trailer may be up to 13.6 metres if the trailer is designed and constructed for the positive control of temperature through the use of refrigerated equipment, has a distance from the articulation point to the rear overhang line of no more than 9.9 metres and does not operate in a B-Double or road train combination and otherwise complies dimensionally. Also, the distance from the front articulation point to the rear overhang line of not more than 9.9 metres; and the vehicle must not operate in a B-Double or Road Train combination.
Car carriers - The distance measured at right angles between the rear overhang line of a trailer carrying vehicles on more than one deck and the rear of the rearmost vehicle on the trailer must not exceed 4.9 metres.
Livestock carriers- A trailer built to carry cattle, horses, pigs or sheep on two or more partly or completely overlapping decks must not have more than 12.5 metres of its length available to carry cattle, horses, pigs or sheep. In a B-double built to carry cattle, horses, pigs or sheep, the two semitrailers must not have more than 18.8 metres of their combined length available to carry cattle, horses, pigs or sheep. Note - the length available for the carriage of cattle, horses, pigs or sheep on a trailer is measured from the inside of the front wall or door of the trailer to the inside of the rear wall or door of the trailer, with any intervening partitions disregarded.
Dimensions relating to specific trailer types
Livestock carriers
- A trailer built to carry cattle, horses, pigs or sheep on two or more partly or completely overlapping decks must not have more than 12.5 metres of its length available to carry cattle, horses, pigs or sheep.
- In a B-double built to carry cattle, horses, pigs or sheep, the two semi-trailers must not have more than 18.8 metres of their combined length available to carry cattle, horses, pigs or sheep.
Note - the length available for the carriage of cattle, horses, pigs or sheep on a trailer is measured from the inside of the front wall or door of the trailer to the inside of the rear wall or door of the trailer, with any intervening partitions disregarded.
Refrigerated van trailers
The front articulation point to the rear of a semi-trailer may be up to 13.6 metres if the trailer is designed and constructed for the positive control of temperature through the use of refrigerated equipment. Also, the distance from the front articulation point to the rear overhang line of not more than 9.9 metres does not operate in a B-double or road train combination and otherwise complies dimensionally.
Car carriers
The distance measured at right angles between the rear overhang line of a trailer carrying vehicles on more than one deck and the rear of the rearmost vehicle on the trailer must not exceed 4.9 metres.