Understanding truck dimensions

Understanding Truck Dimensions

While truck dimensions and weight restrictions are as complex as they are varied, they are paramount to road safety, and exist for that reason.

The Heavy Vehicle National Law (HVNL) was implemented in 2014 in the interest of protecting all Australian road users and preserving the quality and longevity of road infrastructure.

The law covers heavy vehicles over 4.5 tonnes Gross Vehicle mass (GVM) across Queensland, New South Wales, Victoria, South Australia, Australian Capital Territory and Tasmania. This blog provides a snapshot of the current regulations.

When referring to ‘dimensions’, it’s important to note HVNL are encompassing the length, width and height of heavy vehicles (ie. over 4.5 tonnes) and the variety of trailers attached to the vehicles. Regulations are specific to the vehicle & trailer combination.


Dimension Limits Allowed:

-              Width limit for heavy vehicles (over 4.5 tonne GVM) is 2.5 metres

-              Height limit is commonly 4.3 metres with some exemptions for particular trailer types , for example livestock trailers (4.6 metres)


Length Limits

Below are some common length limits:

-              12.5 metres For any rigid truck and most rigid buses

-              19.0 metres for any truck and single trailer combination (including semi-trailers)

-              19.0 metres for pocket B- Double combination

-              26.0 metres for a B-Double combination

-              36.5 metres for Type 1 Road Train

-              53.5 metres for Type 2 Road Train

-              Rear overhang is restricted on trucks to 60% of the wheelbase or 3.7 m, (whichever is shorter)

-              Combination length limits are linked to axle groupings and trailer types.


There are, of course, exceptions to the rule for special vehicle combinations that exceed general limits, through a scheme called Performance Based Standards (PBS). This scheme is in place to ensure vehicles of this nature attain heightened levels of safety.

Take a look at the National Heavy Vehicle Regulators mass and dimension limits face sheet here for a comprehensive rundown on these restrictions to ensure you are adhering to industry laws keeping Australian roads safe.

For more information, visit the NHVR website.

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