Oversize or overmass vehicles

Dimension limits

This page is about vehicle size limits in the Northern Territory.

It is the responsibility of the vehicle operator to check the relevant legislation.


The overall width of a vehicle including any load must not be more than 2.5m. This excludes any lights, mirrors, reflectors, central tyre inflation systems and signalling devices.

Width and height limits of oversize or overmass vehicles

Vehicles with a gross vehicle mass (GVM) of over 3.5 tonne may have mirrors that project an extra 230mm from the widest point of the vehicle, as long as they can fold in to 150mm.


Maximum vehicle height including any load is 4.3m except for:

  • vehicles designed to carry livestock can be up to 4.6m high
  • vehicles designed to carry motor vehicles on more than one deck may be up to 4.6m high
  • double-deck buses can be up to 4.4m high.

Overhanging loads

You may carry loads that are longer or wider than the vehicle itself as long as they are within certain limits.

The rear overhang is measured from the centre of the rear axle or axle group to the extreme rear of the vehicle, including any load on the vehicle.

Overhang dimensions

(i) Rear overhang is measured from the centre of the rear axle or axle group to the extreme rear of the vehicle including any load on the vehicle.
(ii) Rear overhang must not exceed the lesser of 60% of the wheelbase or 3.7m. Rear overhang on loaded car carrier trailers, carrying vehicles on more than one deck, may be up to 4.9m, and is measured from the rear overhang line to the rear of the rearmost vehicle carried on the trailer.

Projecting load to the rear - if a load projects more than 1.2m from the rear of a vehicle, it must carry a warning signal attached to the rear of the load.

In daylight, a warning signal is a brightly coloured flag with sides at least 300mm long.

At night, a warning signal is a red light that can be seen from a distance of at least 200m.

A load must not overhang in a way that is dangerous to people or property even if all dimension and warning requirements have been met - safety is still the main concern.

Any overhang must be contained within the maximum width limit of 2.5m.


The following images show the maximum length for various vehicles and vehicle combinations. All maximum lengths include any load the vehicle may carry.

Rigid vehicles

Rigid vehicles

Articulated bus

Articulated bus

Articulated truck

Articulated truck

A semi-trailer has one axle group to the rear and attaches to a prime mover at the front.

Requirements for the semi and dog trailers

Truck and dog trailer

Dog trailer - length

A dog trailer has an axle group at the front of the trailer that can pivot and is connected to the towing vehicle by a drawbar. There is another axle group at the rear of the trailer.

Truck and pig trailer

Pig trailer

A pig trailer has one axle group or a single axle near the middle of its load carrying area. It is connected to the towing vehicle by a rigid drawbar.

Pig trailer


A B-double is a vehicle combination made up of a prime mover towing two semi-trailers.

B-double truck - length

The length for a B-double truck is measured from the 'king pin' on the forward trailer to the end of the rear trailer as shown above.

Road train

Road train

Road train

A road train is a prime mover or ridid truck towing at least two trailers, that is not considered a B-double.

Car carrier

Car carrier

A car carrier is a truck that is specially designed to carry cars on overlapping decks. Car carriers are not the same as road trains.

More information

For more information go to permit guidelines for oversize and overmass vehicles PDF (5.0 MB).

You can also get a copy of V13 Vehicle dimensional limits (including load) PDF (404.9 KB)

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Last updated: 30 September 2016

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