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Overdimension vehicles and loads (Factsheet 53)

Published: 06 2013

This factsheet summarises some requirements of Land Transport Rule: Vehicle Dimensions and Mass 2002.

Overdimension vehicles and loads

About the 'Vehicle Dimensions and Mass' Rule

This factsheet summarises the 'overdimension' requirements of the Land Transport Rule: Vehicle Dimensions and Mass 2002. including the changes made by Land Tranpsort Rule: Vehicle Dimensions and Mass Amendment 2010 in force from 1 May 2010.

The amendment Rule made no changes to the overdimension permit process, but did change some of the dimension limits. Please refer to Factsheet 13 to determine if your overdimension vehicle or load still requires an overdimension permit. If it does require a permit, follow the steps in this factsheet.

If the load is divisible and you are not over the width or height limits, you may be eligible for a High Productivity Motor Vehicle permit; refer to Factsheet 13g.

What is an overdimension vehicle or load?

An overdimension (or oversize) vehicle or load is one that exceeds one or more of the maximum dimensions allowed for standard vehicles.

If you need information on the maximum sizes for standard vehicles, see Factsheet 13 for definitions and general information, and see other factsheets in the factsheet 13 series for the information specific to your vehicle or your vehicle combination. If you need help,or call our contact centre on 0800 699 000.

Overdimension vehicles or loads are only allowed to operate on an overdimension permit if they are indivisible. (An indivisible load is a load that without an unreasonable amount of effort or expense, or the risk of damage to the load can't be divided into two or more sections for road transport.)

Construction machinery that is carried on an overdimension permit should be loaded so it fits within standard dimension limits, if possible.

There are special operating conditions that overdimension vehicles or loads must meet, based on the size of the vehicles and loads. There are four size categories – 1, 2, 3 and 4 – each larger than the previous one. This factsheet concentrates on the most common, Categories 1 and 2.

If you need information on Category 3 or 4 overdimension vehicles and loads, please contact the Overdimension Permit Issuing Agency (OPIA) – 0800 OVERSIZE (0800 683 774) or fax 06 953 6313.

Note: You need to contact your nearest NZ Transport Agency (NZTA) office if your load is overweight – that is, exceeds the mass (weight) limits in Factsheet 13, Vehicle dimensions and mass.

What are the types of overdimension vehicles and loads?

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.

Overlength indivisible load

A standard motor vehicle may be used to transport an overdimension load provided that 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).

specialist overdimension vehicle with divisible load

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.

The following 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, ground spreaders/sprayers etc.

specialist overdimension vehicle

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

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

overwieght load

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

1. Overdimension transporter carrying overdimension load

correct transportation of 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 overhang or rear overhang limits of a standard vehicle aren't exceeded.
2. Overdimension transporter carrying divisible load (general freight) only

correct transporation of 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 that 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.

Note: You cannot use a specialist overdimension trailer to carry divisible general freight that is not overdimension unless you do have an overdimension load in the other direction.

How to use this factsheet.

Once you have read about types of overdimension vehicles and loads:

1. Study the general operating conditions that all overdimension vehicles must comply with:

2. Work out which category your vehicle (including the load) is in and whether you need a permit:

3. Find out about the specific operating requirements for Category 1 and Category 2 overdimension vehicles, which you'll need to comply with:

4. Carry this factsheet in your vehicle so you can refer to it.

Where you can find out more