Driver Knowledge Tests

What’s a flat deck?

Flat deck is a term that can be applied to utes, light trailers, heavy trailers and trucks.

Flat deck ute. Even though the ute has side gates, they can be folded down so it’s flat
A flat deck trailer must have at least 3 of the sides that fold down.
This isn’t a flat deck trailer, it’s a vehicle transporter. It doesn’t have fold down sides. This does enable the trailer’s deck to be lower, which is better to keep the centre of gravity low.
A prime mover and flat deck semitrailer
Four-axle flat deck dog trailer with no headboard
Flat deck truck with some pretty dodgy-looking load security

The deck can be made of metal, or metal and wood. Wood provides better friction properties, but is damaged more easily.

This load is strapped to a wet metal flat deck trailer. Metal loads on a wet metal flat deck have very little friction, so load security is more tricky.

What are the advantages of a flat deck?

  • Easier to load long items such as poles, packets of wood, concrete beams, etc.
  • Cheaper than alternatives like curtainsiders, hardsiders, cage trailers and wellsides
  • Less wind resistance when being towed empty
  • Lighter than other options, given there’s no structure on top of the trailer (this means more payload can be carried)
  • Can be loaded and unloaded from the top, e.g. by a truck loader crane or tower crane
  • Can take general freight or containers
  • Can be quicker to load and unload compared to a curtainsider.

What are the disadvantages of a flat deck?

  • Items are exposed to the weather and must be tarped if they are sensitive to wind or rain
  • Not suitable for items that are easy to steal
  • Irregularly shaped items can create lots of wind resistance compared to other trailer options.

What load security is available on a flat deck

Most trailers have a headboard which can be used for blocking the load.

There will be one of more of either a rope rail (for chains or ratchet straps), chain hooks or chain slots (for chains) or ISO locks (for containers and flat racks).

Tarps must be used to cover weather-sensitive loads.

How are flat decks used


The other option for utes is a wellside which has formed metal sides, but these are difficult to load in and out. The flat deck provides easy access to load all kinds of farm equipment, while fold-down gates can hold things like light loads of sand or aggregate.

Light trailers

These tend to be used for cars or specific machinery, as well as in agriculture and horticulture as they can be easily loaded using a forklift or telehandler.

Heavy trailers

You can transport large machinery, metal beams, packets of timber, building materials, metal coils, concrete panels and more. You can also load an ISO container to them with or without twist locks.


The same types of goods as are carried on trailers can be carried on trucks (just shorter lengths).

Darren is an expert on driving and transport, and is a member of the Institute of Advanced Motorists

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