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Trailers: Light simple trailers (Factsheet 13d)

Published: 05 2010

This factsheet details of the dimension and mass limits for specific vehicles and vehicle combinations.

Trailers: Light simple trailers

This factsheet describes the legal dimension requirements in Land Transport Rule: Vehicle Dimensions and Mass 2002 of the dimension limits for light trailers. Please refer to Factsheet 13 for general dimension and mass limits and towing requirements.

This factsheet also includes changes made by Land Transport Rule: Vehicle Dimensions and Mass 2010 Amendment, in force from 1 May 2010. Dimensional changes have been highlighted to assist you to quickly determine how you might be affected, and indicate the previous limit.

For definitions of dimension and axle terms see Factsheet 13.

What is a light trailer?

Light trailers are vehicles:

  • without motive power (ie, they don't have pedals or a motor to drive the wheels)
  • with a maximum gross vehicle mass (usually specified by the manufacturer) of 3,500 kilograms or less. (The gross vehicle mass includes the maximum load that the trailer can carry.)

Light trailers includes class TA trailers (up to 0.75 tonnes) and class TB trailers (0.75 tonnes to 3.5 tonnes).

What is a light simple trailer?

A simple trailer has one, two or three axles arranged close together in an axle set. This is attached to the towing vehicle behind the axle closest to the rear of the vehicle.

A simple trailer is the most common type of light trailer. Most boat trailers, caravans, and garden trailers are simple trailers.

How are other types of light trailer classified?

Some boat trailers, caravans or garden trailers cannot be classified as simple trailers. Their design, or the points of attachment to the towing vehicle, is closer to the design described for heavy trailers in Factsheet 13c, Heavy combination vehicles. For details on other types of trailer, read this information on full, semi, simple and pole trailers, as well as A- and B-train combinations.

All the dimension requirements for heavy trailers in Factsheet 13c apply to light trailers, except that:

  • light trailers have no minimum ground clearance (but if the suspension has been modified to less than 100mm ground clearance, it will have to be approved by a Low Volume Vehicle Certifier)
  • vehicles towing light trailers don't have to meet the tow coupling positions specified for heavy trailers
  • the maximum rear overhang for light trailers is 4.0 metres.

Light simple trailer dimension limits

Maximum width

The maximum width for a light simple trailer (including its load) is 2.5 metres (excluding side marker lights and direction indicators and the bulge towards the bottom of the tyre). An additional 25mm is allowed on each side of the vehicle for ropes, lashings, straps, chains, connectors and tensioning devices that are neither permanently nor rigidly fixed to the vehicle; or J-hooks (to secure stock crates or bins).

Maximum length

The maximum length for a light simple trailer (including drawbar and load) is 12.5 metres (previously 11.5 metres). For a towing vehicle and simple trailer combination (including load, but excluding collapsible mirrors), the maximum overall length is 22.0 metres (previously 20.0 metres).

simple trailer dimensions

Maximum height

The maximum height for a light simple trailer (including load) is 4.25 metres. You're allowed an extra 25mm above 4.25 metres for tarpaulins, covers and lashings, straps, chains, covers and related connectors and tensioning devices which aren't permanently or rigidly fixed to the vehicle.

All vehicles must be loaded in a safe manner, with a height appropriate to the type of load.

Maximum forward distance

simple trailer dimensions

For a simple trailer, forward distance means the distance from the rear axis of the trailer to the centre of the point of attachment on the towing vehicle. For definitions of rear axis see Factsheet 13.

The maximum forward distance is 8.5 metres.

Maximum rear overhang

For a simple trailer, rear overhang means the distance from the rear axis to the rear of the vehicle or its load, whichever is greater. For definitions of rear axis see Factsheet 13.

The maximum for all light trailers is 4.0 metres.

Minimum ground clearance

There are no minimum ground clearance requirements for light trailers (but if the suspension has been modified and the ground clearance is less than 100mm, it will have to be approved by a Low Volume Vehicle Certifier).

Maximum front overhang

For simple trailers, front overhang means the distance from the centre of the tow coupling to the foremost point of the vehicle (trailer, including its load). The maximum for light simple trailers is 2.04 metre radius arc ahead of the tow coupling.

Outside turning circle

The combination rigid vehicle and trailer or trailers (excluding collapsible mirrors) must be able to complete a 360-degree turn, to the left and to the right, within a circle of 25.0 metres diameter (wall to wall).

No part of a vehicle in a combination, other than its tow coupling, may come into contact with another vehicle in the combination.

What are the tow coupling requirements?

It is the driver's legal responsibility to ensure the trailer is safely and securely attached to the towing vehicle by an adequate tow coupling.

For a vehicle towing a light simple trailer, the tow coupling position can't be more than the maximum rear overhang allowed for that type of towing vehicle (for more information about towing see Factsheet 13c).

Please note that the maximum allowable length and forward distance of a rigid motor vehicle is less if it is towing a trailer.

Loading and towing a light simple trailer

Loading your trailer safely

If you tow a simple trailer, you need to be aware that the trailer can impose a large weight on the rear of your vehicle. This weight can, by lever action through the chassis of the vehicle, reduce the effective mass bearing on the front axle(s) of your vehicle. It is important, therefore, that you load your trailer carefully so the load is distributed centrally over the axle(s) of the trailer. This will allow your vehicle to maintain front-wheel grip on the road, so you can continue to steer it safely.

Note: There needs to be a downward force, of approximately 10 percent of the weight of the trailer and its load, on the tow coupling of a simple trailer, to ensure it remains stable while being towed.

The number of trailers you can tow

A light rigid vehicle may tow only one trailer.

Light tractors may tow two light trailers if the manufacturer's rating on the tractor allows this, and if the tractor doesn't exceed 50km/h.

A heavy rigid vehicle (but not a bus) may tow two trailers under certain conditions. See Factsheet 13c for more information on towing two trailers with a rigid heavy vehicle.

Intervehicle spacing

Intervehicle spacing means the distance between the towing vehicle (excluding the tow coupling shroud) and the trailer (excluding the drawbar but including the load). The maximum for light simple trailers is 4.0 metres.

There's no minimum spacing. The trailer (or its load) can overhang the towing vehicle.

Requirements for passenger service vehicles towing a trailer

A heavy passenger service vehicle (eg, a bus) may tow only one light trailer (ie only one trailer with a gross vehicle mass up to 3.5 tonnes).

A light passenger service vehicle (eg, a van or taxi) may tow only one light trailer with a gross vehicle less than 2.0 tonnes.

An articulated bus may not tow a trailer.

What speeds are allowed for vehicles towing simple trailers?

  • A light vehicle towing a trailer is limited to a maximum open-road speed of 90km/h.
  • A heavy vehicle towing a trailer is limited to a maximum open-road speed of 90km/h.
  • School buses towing a trailer are limited to maximum open road speed of 80km/h.

Drivers also need to obey any lower speed limits that apply on particular roads.

What are the limits for projecting loads?

Vehicles may carry loads that are higher, longer or wider than the vehicle itself, provided the load doesn't exceed the maximum permitted dimensions for that class and type of vehicle, and provided the vehicle can be moved safely when loaded. It's the operator's responsibility to ensure the load is properly secured to the vehicle so the vehicle remains stable at all times.

You need to read Factsheet 53, Overdimension vehicles and loads if the load exceeds any of the standard dimension limits.

Loads that overhang the outside of the body or deck of the vehicle by more than 1m to the front or rear, or more than 200mm to the left or right side, need to carry special warning devices attached to the overhanging end(s) of the load, see Factsheet 13.

During the hours of daylight, there must be either:

  • a clean white, or fluorescent red, orange or yellow flag, at least 400mm long by 300mm wide, or
  • a frangible hazard warning panel, at least 400mm long by 300mm wide, showing an orange diagonal stripe (200mm wide) against a yellow green background, facing forwards or rearwards.

During the hours of darkness, the flags or hazard panels must be replaced with lights attached to the load.

  • Loads more than 1 metre wide and extending more than 1 metre from the rear of the vehicle must have one red lamp (facing toward the rear) on each side of load.
  • Loads up to 1 metre wide and extending more than 1 metre from the rear of the vehicle must have one red lamp (facing toward the rear) at the centre of load.
  • Loads more than 1 metre wide and extending from the front of the vehicle must have one white or amber lamp (facing toward the front) on each side of load.
  • Loads up to 1 metre wide and extending more than 1 metre from the front of the vehicle must have one white or amber lamp (facing toward the front) at the centre of load.
  • Loads extending more than 200mm beyond the side of the body of the vehicle must have one red lamp (facing toward the rear) on each side of the load at the rear and one white or amber lamp (facing toward the front) on each side of the load at the front.

These lights need to be clearly visible in clear weather at a distance of at least 200 metres during the hours of darkness.

Displaying these lights at night is an operating requirement that applies to all vehicles, regardless of when they were first registered.

Trailer with boat as load and motor projecting more than 1 metre behind.

In the diagram above, the boat is the load on the trailer. It has a raised outboard motor that projects more than 1 metre behind the rear of the trailer.

If the distance from the rear of the trailer to the most rearward point of the load is more than 1 metre (and the projecting part is less than 1 metre wide), one warning device must be attached to the centre of the projecting part of the load:

  • In daylight, this may be a flag or hazard panel (facing backwards).
  • During the legal hours of darkness, this may be a red light visible from at least 200 metres away.

Where can I find more information on towing and loading?

Refer to the NZTA publication Guide to safe loading and towing for light vehicles.

Where can I find out more?

Contact details:

  • Email us: info@nzta.govt.nz.
  • Call our contact centre: 0800 699 000.
  • Write to us: NZ Transport Agency, Private Bag 6995, Wellington 6141.