Trailer Operational Guidelines

Both light and heavy vehicles towing a trailer are limited to a maximum open-road speed of 90km/h. School buses towing a trailer are limited to the maximum open road speed of 80km/h. Drivers also need to obey any lower speed limits that apply on particular roads.

If you tow a light trailer, you need to be aware that the trailer can impose a large weight on the rear of your tow 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 the front-wheel grip on the road, so you can continue to steer it safely.

Note: Look in your vehicle manual for the maximum weight your vehicle can tow. In addition, there needs to be a downward force, approximately 10% of the weight of the trailer and its load, on the tow coupling of a simple trailer for stable towing.

The maximum rear overhang for light trailers is 4 meters and is measured from the halfway point between two axles, or the 2^nd axle in a tri-axle set, to the rear of the trailer or its load, whichever is greater.

For light trailers, the front overhang is the distance from the center of the tow coupling, to the foremost point of the vehicle (including its load). The maximum is 2.04 meters radius arc ahead of the tow coupling.

The inter-vehicle spacing is 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 trailers is 4 meters, and there is no minimum spacing. The trailer (or its load) may overhang the towing vehicle.

Each trailer has a maximum safe laden weight. Overloading a trailer beyond this weight can compromise the trailer's body, chassis, brake systems, suspension and/or coupling. The maximum safe laden weight minus the unladen weight gives you the maximum load (including objects, people and animals) that the trailer can carry.

To arrange loads safely:

• Check that any goods or animals inside or on your trailer are placed where they won't injure anyone or distract the driver.
• If following another vehicle, make sure that any passengers are sitting in a safe position, using a safety belt or child restraint.
• Spread a load of goods out evenly across the floor or deck of the trailer, to keep its height as low as possible.
• If you have to stack the load, put larger and heavier items at the bottom.
• If possible, arrange loads so they don't project outside the body of the trailer. Minimize any projecting loads so you reduce the risk of injury to the driver, passengers, and other road users.
• Position loads, especially the heavier items, on trailers as close to the axle as possible. Avoid placing heavier loads towards the rear of the trailer. Ensure there is a downward force at the point of attachment, to improve the handling characteristics when you are towing.
• If part of the load is removed during the journey, you may need to rearrange and re-secure the rest of the load.

All loads on trailers should be properly restrained so they can't shift around while the vehicle is moving. All objects should be restrained by being:

• Securely packed inside compartments that are rigidly attached to the trailer, or
• Held securely in racks or cradles or frames designed to fit that size of the object and which are rigidly attached to the trailer, or
• Held by lashings (webbing straps, ropes, chains) or clamps securely attached to appropriate anchorage points (rails, hooks or eyes) on the trailer.

When you secure a load, bear in mind that it will try to move:

• Forwards when the vehicle brakes.
• Sideways when the vehicle turns.
• Backward when the vehicle accelerates.
• Upwards when the vehicle goes over bumps.

If you're using lashings to secure a load, you'll need to work out the strength of the lashings - known as ‘lashing capacity’.  Look on the lashing or its packaging for a figure (in kilograms) besides ‘lashing capacity’. If you see ‘breaking strength’ – then the lashing capacity will be half of this figure. Fasten your load to the vehicle using as many lashings as required to achieve a combined lashing capacity equal to at least twice the weight of the load.

Note: A minimum of two lashings should be used to prevent the load, or part of the load, from twisting, rotating, pivoting or slewing. Secure lashings to suitable anchorage points (rails, hooks or eyes) on the trailer.

Regular maintenance of your trailer is very important:

• Check tire pressures, and look for signs of wear or damage.
• Clean all lights and reflectors.
• Check that all lights are working condition.
• Check with your local garage to ensure the tow coupling and brake mechanisms are well lubricated.
• Jack the trailer up and spin the wheels, listening for rumbling noises and feeling for wheel sway, which indicates worn wheel bearings and unfastened nuts.
• Check that all tie-down points are tight.

A poorly maintained trailer can be a hazard to yourself and other road users. No matter how good you are at towing, a badly maintained trailer poses a significant risk to the safety of all road users.