AU Heavy Vehicle Knowledge Exam Questions & Answers 2026 (21–30)

Question 1

When distributing a load on a rigid heavy vehicle, why is it important to keep the centre of gravity as low as possible?

TheoryPractice · Accepted Answer

To reduce the risk of rollover by improving the vehicle's stability. Keeping the centre of gravity low reduces the overturning moment on the vehicle, significantly lowering the risk of rollover during cornering, braking, and emergency manoeuvres.

Question 2

Under the HVNL, which of the following parties is considered part of the Chain of Responsibility for load restraint compliance?

TheoryPractice · Accepted Answer

Any party in the transport chain whose actions influenced the breach, including consignors, packers, loaders, and operators. The HVNL Chain of Responsibility provisions hold all parties — including consignors, packers, loaders, operators, and drivers — liable if their actions or omissions contributed to a load restraint breach.

Question 3

A B-double combination has a Gross Combination Mass (GCM) limit of 68.5 tonnes. The prime mover has a GVM of 24 tonnes, the lead semi-trailer has a GVM of 22.5 tonnes, and the rear semi-trailer has a GVM of 22 tonnes. What is the maximum total loaded mass the combination may legally carry?

TheoryPractice · Accepted Answer

The sum of all three GVMs — 68.5 tonnes — but only if each axle group limit is also satisfied. The GCM sets the upper limit for the whole combination, but the legal mass is also constrained by individual axle group limits; both the GCM cap and each axle group limit must be simultaneously satisfied.

Question 4

Under standard Australian heavy vehicle dimension rules, what is the maximum permitted overall length for a rigid truck (not a combination) operating under general access conditions?

TheoryPractice · Accepted Answer

12.5 metres. Under the nationally harmonised Heavy Vehicle (Mass, Dimension and Loading) National Regulation, the general access length limit for a single rigid truck is 12.5 metres.

Question 5

Which statement about axle spacing and axle group mass limits under the HVNL is correct?

TheoryPractice · Accepted Answer

Greater axle spacing generally allows higher permissible mass for that axle group due to reduced road stress. Under the HVNL mass schedule, greater spacing between axles in a group typically permits a higher mass limit because the load is spread over a longer section of pavement, reducing peak road stress.

Question 6

Under the HVNL, a 'class 1 heavy vehicle' (oversize/overmass) permit condition requires the driver to carry a copy of the permit at all times during the journey. If an authorised officer requests to inspect the permit and the driver cannot produce it, what is the correct legal position?

TheoryPractice · Accepted Answer

The officer may direct the driver to stop the journey until the permit is produced or confirmed. Under the HVNL, an authorised officer has the power to direct a driver to stop and not proceed with a regulated heavy vehicle journey if required documentation such as a permit cannot be produced for inspection.

Question 7

A semi-trailer carrying coiled steel is loaded so that the load rests against fixed headboards and is secured with four lashings rated at 4 000 daN each. The coils have a total mass of 18 000 kg. Assuming the headboard is structurally approved and rated to take forward loads, what minimum rated lashing restraint capacity is required for the remaining three directions (rearward, lateral, and vertical) under the performance standard?

TheoryPractice · Accepted Answer

At least 50% of load mass (9 000 kg) rearward, 50% (9 000 kg) laterally each side, and 20% (3 600 kg) vertically. The Load Restraint Guide performance standard requires 100% of load mass forward, 50% rearward, 50% laterally on each side, and 20% vertically; a compliant headboard can satisfy the forward requirement, leaving the other three directions to be met by the lashings.

Question 8

When should a heavy vehicle driver conduct a pre-trip inspection of their vehicle?

TheoryPractice · Accepted Answer

Before commencing any journey, every time the vehicle is used. Under the Heavy Vehicle National Law, drivers have a primary duty to ensure their vehicle is safe and roadworthy, which requires a pre-trip inspection before each journey to identify any defects.

Question 9

During a daily pre-trip check, you notice a headlight is not functioning. What is the correct action?

TheoryPractice · Accepted Answer

Report the defect and have it repaired before driving on a public road. Under the HVNL, a driver must not operate a vehicle with a defect that makes it unsafe or non-compliant; a defective light must be reported and rectified before the vehicle is used on a public road.

Question 10

When checking tyre condition on a heavy vehicle before a trip, which of the following would make a tyre unroadworthy?

TheoryPractice · Accepted Answer

Tread depth of less than 1.5 mm anywhere across the tread. Australian Road Rules and vehicle standards require heavy vehicle tyres to have a minimum tread depth of 1.5 mm across the full width of the tread; anything less renders the tyre unroadworthy.

AU Heavy Vehicle Knowledge Exam Questions & Answers 2026 (21–30)

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