VIC Heavy Rigid Knowledge Test common mistakes
VIC Heavy Rigid Knowledge Test · Understand the traps and how to avoid them.
Treating the GVM on the compliance plate as the payload allowance - loading the truck to GVM without subtracting the tare mass, and ignoring GCM entirely when a trailer is attached.
GVM is the number people see quoted in ads, registration papers and licence definitions, so it gets mentally filed as 'how much I can carry'. GCM is rarely mentioned day to day and only bites once a trailer or dog trailer is hooked up.
What to do instead
Learn the three-mass hierarchy as a single worked example: GVM = tare + payload; GCM = loaded prime mover/rigid + loaded trailer(s); and no axle group may exceed its own limit even when the total is legal. Practise one calculation with real numbers (e.g. tare 8.5 t, GVM 15 t, so maximum payload 6.5 t) until the subtraction becomes automatic.
Assuming a Heavy Rigid licence lets you tow a trailer of any size, or that an HR truck can be driven with a car-style trailer endorsement logic.
Candidates generalise from the car licence system, where the class of vehicle you can drive and the trailer you can tow are only loosely connected. The HR trailer limit is a specific figure that appears in the licence definition and nowhere in everyday driving.
What to do instead
Memorise the HR definition as two numbers: a rigid motor vehicle with a GVM over 8 tonnes, towing a trailer with a GTM not over 9 tonnes. If a question pairs an HR truck with a heavy trailer, check the 9 tonne GTM figure before answering.
Performing the pre-start check as a cab-side formality - ticking boxes without walking around the vehicle, and without checking coupling security, tyre condition and a stationary brake test.
Scheduling pressure and familiarity with the same truck every day. Drivers feel the vehicle 'drove in fine yesterday', so the check becomes a signature rather than an inspection.
What to do instead
Adopt a fixed sequence that physically moves you around the vehicle: start at the driver's door, work clockwise, finish with the engine running checks (air build-up and leak-down, brake test, lights). Treat the checklist as a route map, not a memory test - the sequence is what stops you skipping the kingpin or the inside duals.
Not knowing what to do once a defect is found - driving on with a defect that should ground the vehicle, or failing to record and report a defect that was identified.
Candidates study defects as a list of parts to look at but never learn the consequence step. In the yard, there is also pressure to 'get the load there' rather than park the truck.
What to do instead
Learn the classification and its consequence as one unit: a major defect means the vehicle must not be driven until repaired; a minor defect must be reported and recorded. Know that the report goes to the operator and into the defect record/work diary, and that the driver who identifies the defect owns the report.
Getting the load restraint performance standards wrong - quoting 100% of the load's weight in every direction, or guessing at figures like 60% or 'half the weight'.
The percentages feel arbitrary and are easy to half-remember, and in practice many drivers restrain loads 'tight enough' by feel rather than to a specified standard.
What to do instead
Lock in the three figures: the restraint system must withstand 80% of the load's weight forward, 50% rearward and 50% sideways. Remember it as 'forward is the hardest stop' - the forward figure is the largest because that is where the load moves under heavy braking.
Securing the load once at the start of the trip and never re-checking it, including after heavy braking or rough road sections.
Straps stretch, webbing settles, and loads compact over the first few kilometres. Drivers assume 'I tensioned it, so it is tensioned' and only look again if something feels wrong.
What to do instead
Build re-checks into the trip plan: a stop within the first 20–50 km to re-tension and confirm the load has not shifted, then another check at every rest stop and after any heavy braking or off-road section. Loose or damaged straps and missing edge protection are replaced, not reused.
Descending long or steep grades on the footbrake alone, riding the pedal to hold speed, rather than selecting a low gear and using engine braking before the descent begins.
Car habits transfer directly - in a car you brake to slow down, and the gearbox is almost incidental. Candidates also fear over-revving and so stay in a high gear.
What to do instead
Change down and set the speed before the crest, not once the descent has started, and use short firm brake applications rather than continuous light pressure so the brakes have time to cool. Know the signs of brake fade and the escape options if fade occurs.
Applying a two-second following gap, or judging the gap by 'feel', when driving a loaded heavy vehicle.
The two-second rule is the one most strongly associated with learner driving and is the number candidates remember. Mass, tyre condition and load all lengthen stopping distance, but none of that is visible in the gap itself.
What to do instead
Use a three-to-four second minimum in good conditions and add time for a loaded vehicle, wet roads, night or following another heavy vehicle. Count it against a fixed roadside object, not by eye, and remember the vehicle behind you may need more room than you do.
Filling in the work diary retrospectively at the end of the shift and treating loading, unloading and waiting at a depot as rest.
The diary feels like paperwork to be tidied up later, and waiting around a site feels like time off. Both assumptions understate work time and hide an approaching limit.
What to do instead
Record at each change of activity, not at day's end, and count loading, unloading, inspecting, cleaning and waiting on duty as work time. Plan the required minimum break before you reach the continuous work limit under standard hours, and carry the diary with you and retain it as required.
Misreading heavy-vehicle signage - passing a load-limited bridge without comparing the sign to the actual loaded mass, or ignoring a low clearance sign because the truck 'fits under it empty'.
These signs are read as advisory car-style warnings, and the truck's height is mentally fixed at its unladen height. Load limits are also compared to GVM rather than to what the vehicle actually weighs at that moment.
What to do instead
Know that a load limit sign applies to the actual gross mass of the vehicle at that time, not to its GVM or its registration, and that a clearance sign applies to your height including any load or raised equipment. Where the margin is close, stop and check rather than proceed on assumption.