This technical advisory procedure provides best practice advice for achieving dynamic stability with truck and dog combinations.

Under the Australian Design Rules, the truck and towed dog trailer are assessed as two separate vehicles, which may then be put together into a truck and dog combination. While completely legal, this means that operators may not receive guidance on how they can optimise the safety and stability of these combinations.

This advisory procedure provides step-by-step instructions and formulas to help operators improve the overall performance, dynamic stability and safety of their truck and dog combinations.

The formulas cover five different common truck and dog combinations between 42.5 and 50 tonne Gross Combination Mass. In general, the formulas promote longer wheelbases for both the truck and trailer, reducing coupling offset, and lowering the combination’s centre of gravity.