Factsheet 53 – August 2009

Types of overdimension vehicles and loads

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Standard-sized motor vehicles carrying overdimension loads

Example: A rigid truck that doesn't normally exceed the standard dimension limits but is being used to transport an overwidth tank or long load.

A standard motor vehicle may be used to transport an overdimension load as long as the load is indivisible, and is loaded in a way that minimises its width. (Unless the load's height or instability, or both, makes it necessary to transport the load sideways).

A standard motor vehicle may transport more than one overdimension load, if the loads:

• aren't wider than 2.5 metres if they're loaded side by side
• aren't higher than 4.25 metres if they're loaded one above the other
• aren't longer than the standard length or rear overhang limits for that vehicle if they're loaded one behind the other.

These combination motor vehicles can't exceed the standard rear overhang or overall length limits:

• A truck and simple trailer.
• A truck and full trailer.
• An A-train truck.
• A B-train truck.

Specialist overdimension vehicles

Example: Chip spreaders, forklifts, mobile cranes, snow ploughs etc.

Specialist overdimension vehicles aren't primarily designed to transport overdimension or overweight loads, but they can exceed the limits for standard vehicles if:

• the vehicle's primary purpose is to carry out a specialist function that requires overdimension equipment, and
• dismantling the vehicle's overdimension equipment would make the vehicle unusable for its intended purpose, or
• it would take more than four hours to dismantle the equipment.

A specialist overdimension motor vehicle may transport a divisible load, but it can't exceed the maximum standard dimension limits if those limits can be complied with by reducing the size of the vehicle's divisible load.

Overdimension vehicles designed for overdimension or overweight loads

Examples: Low loaders, three or four rows of eight transporters, multi-axle house trailers, platform trailers.

The following three scenarios show how these vehicles, commonly referred to as overdimension transporters, can be loaded.

1. Overdimension transporter carrying an overdimension load

An overdimension transporter can carry an overdimension load if the load:

• is indivisible, and
• is loaded in a way that minimises its width (unless the load's height or instability (or both) makes it necessary to transport the load sideways).

An overdimension transporter may transport more than one overdimension load if:

• side by side, the total width isn't greater than 2.5 metres
• one above the other, the total load isn't higher than 4.25 metres
• one behind the other, the length, front or rear overhang limits of a standard vehicle aren't exceeded.

2. Overdimension transporter carrying an overdimension load and a divisible load

If an overdimension transporter is carrying an overdimension load and a divisible load (general freight), the overdimension transporter must be reduced to the smallest dimension practicable to carry the indivisible load.

This means widening trailers must be closed to their narrowest width, and tromboning trailers must be reduced to their shortest forward distance.

This means widening trailers must be closed to their narrowest width, and tromboning trailers must be reduced to their shortest forward distance.

Overdimension transporters may transport divisible goods if the goods:

• side by side, don't overhang the deck and the deck has been reduced to its smallest width
• one above the other, aren't higher than 4.25 metres, and
• one behind the other, don't overhang the deck and the deck has been reduced to its shortest length.

3. Overdimension transporter carrying divisible load (general freight) only

If an overdimension transporter is only carrying a divisible load (general freight), (ie, it isn't transporting an overdimension load), the transporter must be reduced to the smallest dimension practicable. Widening trailers must be closed to their narrowest width, and tromboning trailers must be reduced to their shortest forward distance.

An overdimension transporter may transport divisible goods if:

• one direction of the vehicle's journey requires the overdimension vehicle to transport an overdimension load, or
• the weight or instability of the divisible load requires the use of the overdimension motor vehicle

If the two points above are true, then the three points below must also be met:

• Side by side, the goods don't overhang the deck and the deck has been reduced to its smallest width, and
• One above the other, the goods aren't higher than 4.25 metres, and
• One behind the other, the goods don't overhang the deck and the deck has been reduced to its smallest length.