This page describes the legal dimension requirements in Land Transport Rule: Vehicle Dimensions and Mass 2016 of the dimension limits for light trailers
Also read Vehicle dimensions and mass for general dimension and mass limits and towing requirements.
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 (GVM), usually specified by the manufacturer, of 3500 kilograms or less. (The GVM includes the maximum load that the trailer can carry.)
Light trailers includes class TA trailers (GVM up to 0.75 tonnes) and class TB trailers (GVM from 0.75 tonnes to 3.5 tonnes).
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 towing vehicle.
A simple trailer is the most common type of light trailer. Most boat trailers, caravans, and garden trailers are simple trailers.
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 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 Heavy combination vehicles apply to light trailers, except that:
light trailers have no minimum ground clearance
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.
The maximum width for a light simple trailer (including its load) is 2.55 metres (excluding side marker lights and direction indicators and the bulge towards the bottom of the tyre).
The maximum length for a light simple trailer (including drawbar and load) is 12.5 metres. For a towing vehicle and simple trailer combination (including load, but excluding collapsible mirrors), the maximum overall length is 22 metres.
The maximum height for a light simple trailer (including load) is 4.3 metres.
All vehicles must be loaded in a safe manner, with a height appropriate to the type of load.
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.
The maximum forward distance is 8.5 metres.
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.
The maximum for all light trailers is 4.0 metres.
There are no minimum ground clearance requirements for light trailers.
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.
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 metres diameter (kerb to kerb).
No part of a vehicle in a combination, other than its tow coupling, may come into contact with another vehicle in the combination.
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 Heavy trailers and combination vehicles).
Please note that the maximum allowable length and forward distance of a rigid motor vehicle is less if it is towing a trailer.
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.
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 Heavy trailers and combination vehicles for more information on towing two trailers with a rigid heavy vehicle.
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 four metres.
There’s no minimum spacing. The trailer (or its load) can overhang the towing vehicle.
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
A light passenger service vehicle (eg a van or taxi) may tow only one light trailer with a gross vehicle less than two tonnes.
An articulated bus may not tow a trailer.
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.
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 our section about 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 Vehicle dimensions and mass.
During the hours of daylight, there must be either:
a clean white, or fluorescent red, orange or yellow flag, at least 400 millimetres long by 300 millimetres wide, or
a hazard warning panel, at least 400 millimetres long by 300 millimetres wide, showing an orange diagonal stripe (200 millimetres wide) against a yellow green background, facing forwards or rearwards, or
a hazard warning panel, at least 300 millimetres long by 400 millimetres wide showing an orange diagonal stripe (200 millimetres wide) against a yellow-green background, facing forwards or rearwards, or
a hazard warning panel, at least 600 millimetres high by 200 millimetres wide showing an orange diagonal stripe (300 millimetres wide) against a yellow/green background facing forwards or rearwards.
Note: Hazard warning panels that extend beyond the edge of the vehicle must be frangible (breakable or readily deformable).
During the hours of darkness, the flags or hazard panels may be displayed and lights must be attached to the load as follows:
Loads more than one metre wide and extending more than one metre from the rear of the vehicle must have one red lamp (facing toward the rear) on each side of load. Loads up to one metre wide and extending more than one metre from the rear of the vehicle must have one red lamp (facing toward the rear) at the centre of load.
Loads more than one 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 one metre wide and extending more than one 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 200 millimetres 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.
In the diagram above, the boat is the load on the trailer. It has a raised outboard motor that projects more than one 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 one metre (and the projecting part is less than one 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 must be a red light visible from at least 200 metres away. The flags or hazard panels may also be displayed.