Cambodia Heavy Vehicle Driving Test common mistakes
Cambodia Heavy Vehicle Driving Test · Understand the traps and how to avoid them.
Treating the posted speed limit as the target speed and answering that a heavy truck may always travel at the car limit, instead of selecting a safe speed for load, gradient, road surface and visibility.
Candidates memorise the numeric limits for cars and motorcycles and assume one limit covers every vehicle class; they do not connect the limit to the vehicle's stopping distance when fully loaded.
What to do instead
Learn the limits by vehicle category and rehearse the rule that the limit is a ceiling, not a target; for each practice question ask what the truck's stopping distance and stability would be at that speed in the stated conditions before choosing an answer.
Answering that the driver may proceed on a green light without checking that the intersection is clear, or that a green arrow permits any movement rather than only the arrowed movement.
Signal questions are answered by colour association alone; candidates skip the conditional part of the rule about blocked intersections and filter arrows.
What to do instead
Study signals as permission plus condition: green means proceed only if the exit is clear, arrows authorise only the indicated direction, and flashing signals change priority. Practise by describing each signal aloud with its condition attached.
Confusing regulatory signs with warning signs, for example treating a circular red-bordered sign as advisory or a triangular sign as a prohibition, and misreading supplementary plates that limit the sign to certain vehicles or times.
Shape and colour conventions are learned superficially, and the small supplementary plate under the main sign is ignored because attention stops at the symbol.
What to do instead
Build a shape-colour-meaning table (circle with red border = prohibition, triangle = warning, rectangle = information or direction) and always read the plate beneath the sign in practice sets; answer only after identifying shape, symbol and plate together.
Answering load-security questions by describing rope or tarpaulin coverage only, omitting rated lashing capacity, number of attachment points, load distribution against axle limits, and rear overhang marking.
Candidates think of load security as 'tie it down' and have no mental model of aggregate lashing capacity versus load mass, or of how load position changes axle loads.
What to do instead
Learn the principle that total lashing strength must exceed the load's forward and lateral forces, that load must sit within axle and gross limits, and that projecting loads need markers. Practise by calculating axle load shifts when a load is moved forward or back.
Using only the service brake on a long descent with a loaded vehicle and answering that this is correct, rather than selecting a lower gear before the descent and using engine braking with intermittent brake application.
Candidates transfer light-vehicle habits to heavy vehicles and do not understand brake fade from continuous application, nor that brakes are cooled by airflow only when released.
What to do instead
Memorise the descent procedure: select the gear before the slope, keep brakes cool by applying firmly and releasing, never coast in neutral, and stop to let brakes cool if fade is suspected. Link every braking answer to heat, fade and stopping distance.
Answering fatigue questions with 'stop and rest' but not stating the required rest duration, the role of breaks during the journey, or that caffeine and open windows are only short-term measures that do not restore fitness.
The general principle is known but the specific numbers and the rejection of ineffective countermeasures are not, so the chosen option sounds sensible but is incomplete.
What to do instead
Learn the rest and break rules as numbers, plus the rule that only sleep restores alertness. When a question offers a 'cure' such as coffee, music or fresh air, mark it as a temporary measure and look for the answer that includes stopping and sleeping.
Treating the alcohol limit as a single figure for all drivers and answering that a heavy vehicle driver may drive at the private-car limit, or that time or coffee speeds elimination.
Candidates learn one number and do not distinguish professional or heavy-vehicle thresholds, and they carry the myth that sobering-up techniques work.
What to do instead
Learn the limits by licence class and remember that elimination is by time only, roughly a fixed rate per hour with individual variation. For any alcohol question, first identify the driver category, then apply the stricter limit.
Giving first aid answers that move an injured motorcyclist or suspected spinal case, remove a helmet, or give food and drink, instead of securing the scene, calling emergency services and keeping the casualty still and warm.
Candidates focus on being helpful and skip scene safety and the ABC priority order; helmet removal feels caring but is dangerous without training.
What to do instead
Learn a fixed sequence: stop and secure the scene with warning triangles, call emergency services with location and casualty count, then airway, breathing, circulation, control bleeding and treat for shock without moving the casualty unless there is fire or traffic danger.
Answering licensing questions by naming a category letter without matching it to the vehicle's gross vehicle mass, passenger capacity or trailer combination, and confusing a learner or provisional stage with a full licence.
Category letters are memorised as a list rather than as mass-based thresholds, and the conditions attached to learner and provisional stages are skipped.
What to do instead
Build a table of each category with its gross vehicle mass, trailer and passenger thresholds and the conditions of each stage. For every question, first state the vehicle's mass and combination, then select the category that covers it.
In hazard-perception questions, choosing the first hazard seen and stopping there, or answering what the driver should have done after the event rather than what to do in the next few seconds.
Candidates read the scenario once and answer from instinct, missing the developing hazard such as a pedestrian behind a parked truck or a cyclist in a blind spot, and they confuse hindsight with anticipation.
What to do instead
Use a scanning routine on every scenario: mirror and blind spot, road edges, junctions, and anything that could enter your path. Name at least two hazards and the planned response for each before selecting an answer, and prefer the option that reduces speed and increases space early.