I85PREP
⌘ K
Cambodia Heavy Vehicle Driving Test study materials
Cambodia Heavy Vehicle Driving Test study resources

Cambodia Heavy Vehicle Driving Test practice questions

One question at a time. Build your Cambodia Heavy Vehicle Driving Test understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Traffic law, signs, signals and road markings

Under Cambodian traffic law, what does a circular sign with a red border and a red diagonal slash across a black symbol generally indicate?

  1. An information point for tourists
  2. A mandatory instruction to follow
  3. A prohibition that road users must obey Correct answer.
  4. A warning of a hazard ahead

Explanation

Circular signs with a red rim belong to the regulatory group, and the red diagonal slash cancels the activity shown inside, making it a prohibition. Warning hazards use triangular signs, and mandatory instructions use blue circles without a slash.

Question 2Traffic law, signs, signals and road markings

A heavy truck approaches an intersection where a traffic police officer stands with the right arm raised vertically and the palm facing traffic. What must the driver do?

  1. Sound the horn and proceed slowly
  2. Continue through if the light is green
  3. Turn right without stopping
  4. Stop and wait for the officer's next signal Correct answer.

Explanation

A raised arm with the palm toward oncoming traffic is the police signal to stop, and it overrides the traffic light. Drivers must halt before the stop line or the intersection and wait until the officer gives a release signal.

Question 3Traffic law, signs, signals and road markings

What is the meaning of a solid continuous white line along the centre of a two-way road in Cambodia?

  1. Overtaking across the line is prohibited Correct answer.
  2. Parking is allowed on the line
  3. The speed limit changes at that point
  4. The lane is reserved for buses

Explanation

A continuous centre line tells drivers they may not cross it, which in practice bans overtaking and U-turns that cross the line. Broken lines permit crossing when it is safe, so the solid line marks a stricter restriction.

Question 4Traffic law, signs, signals and road markings

At a junction controlled by a flashing red traffic light, what is the correct action for a heavy vehicle driver?

  1. Proceed without slowing down
  2. Stop, then proceed only when it is safe Correct answer.
  3. Sound the horn and continue at speed
  4. Wait until the light turns green

Explanation

A flashing red light functions like a stop sign: the driver must come to a complete stop and then yield to other traffic before moving off. It does not mean the road is closed, nor does it require waiting for a green phase that may not come.

Question 5Traffic law, signs, signals and road markings

Which document must a heavy goods vehicle driver be able to present during a roadside check in Cambodia?

  1. A copy of the vehicle's purchase invoice
  2. A valid driving licence of the correct class Correct answer.
  3. A letter from the vehicle manufacturer
  4. A certificate of vehicle washing

Explanation

Drivers must hold and carry a driving licence of the class that matches the vehicle they operate, and police may demand it at a checkpoint. Other required papers such as registration and insurance belong to the vehicle, but a purchase invoice is not a driving document.

Question 6Traffic law, signs, signals and road markings

A sign shows a black arrow bending sharply to the left inside a red-bordered triangle. What does this tell a truck driver?

  1. A left lane is closed
  2. A sharp left bend is ahead Correct answer.
  3. A left-side parking area is near
  4. A left turn is forbidden

Explanation

Triangular signs with a red border give warning of a hazard, and a bent arrow inside them warns of a bend in the direction shown. Because heavy vehicles have a high centre of gravity, the driver should reduce speed before entering the curve.

Question 7Traffic law, signs, signals and road markings

When a heavy truck is travelling on a road with three lanes in the same direction, which lane should the driver normally use?

  1. The middle lane at all times
  2. The leftmost lane, keeping the right lanes for overtaking Correct answer.
  3. The rightmost lane at all times
  4. Any lane, chosen at random

Explanation

Cambodian traffic keeps to the right, so the normal driving lane is the leftmost lane of a multi-lane carriageway and the lanes to the right are used for overtaking. A heavy vehicle should return to the left lane once the overtaking manoeuvre is complete.

Question 8Traffic law, signs, signals and road markings

What does a blue circular sign containing a white arrow pointing straight ahead mean?

  1. Traffic must proceed straight ahead Correct answer.
  2. A pedestrian crossing is ahead
  3. A roundabout is ahead
  4. Straight ahead is closed

Explanation

Blue circular signs give mandatory instructions, and a white arrow inside one directs traffic to follow the direction shown. Unlike a triangular warning sign, it does not merely advise; it requires the manoeuvre.

Question 9Traffic law, signs, signals and road markings

A truck driver reaches a level crossing where a red light is flashing and the barrier is beginning to lower. What is the required action?

  1. Stop before the crossing and wait Correct answer.
  2. Accelerate to pass under the barrier
  3. Stop on the tracks and check both ways
  4. Drive around the barrier on the shoulder

Explanation

A flashing red light at a level crossing, together with a moving barrier, means a train is approaching, so the driver must stop clear of the tracks. Stopping on the tracks or trying to beat the barrier risks a collision with the train.

Question 10Traffic law, signs, signals and road markings

What is the purpose of a yellow box junction marking painted on the road surface?

  1. To mark a permitted parking zone
  2. To indicate a bus stop
  3. To show where overtaking is allowed
  4. To keep the area clear of stopped vehicles Correct answer.

Explanation

A yellow box marks an area that must not be blocked, so a driver may enter only when the exit is clear. This prevents queuing vehicles from obstructing cross traffic at busy junctions.

Question 11Traffic law, signs, signals and road markings

A driver wishes to overtake a slower vehicle on a two-lane road. Which condition must be satisfied before the manoeuvre begins?

  1. The vehicle ahead is signalling a right turn
  2. The road ahead is clear and overtaking is permitted by markings Correct answer.
  3. The overtaking vehicle is fully loaded
  4. The driver's horn has been sounded twice

Explanation

Overtaking is lawful only where the markings allow it and the driver has a clear view of oncoming traffic with enough distance to complete the pass. Sounding a horn or the load state of the vehicle does not create a safe gap.

Question 12Traffic law, signs, signals and road markings

What does a red circle containing the number 40 in black mean for a heavy vehicle driver?

  1. The road is 40 metres wide
  2. The minimum permitted speed is 40 km/h
  3. The maximum permitted speed is 40 km/h Correct answer.
  4. The vehicle must be 40 metres from the junction

Explanation

A number inside a red-bordered circle is a regulatory speed limit expressed in kilometres per hour, and it applies to all vehicles covered unless a separate plate says otherwise. Drivers must keep their speed at or below that figure.

Question 13Traffic law, signs, signals and road markings

A truck driver is involved in a collision that causes injury to another person. What is the driver's legal duty at the scene?

  1. Exchange no information and drive away
  2. Stop, give assistance and report to the police Correct answer.
  3. Continue the journey and report the next day
  4. Leave the scene to fetch a mechanic

Explanation

Cambodian traffic law requires any driver involved in a crash causing injury to stop immediately, render assistance and notify the police. Fleeing the scene is a serious offence that carries heavier penalties than the original collision.

Question 14Traffic law, signs, signals and road markings

On a road where the centre line is broken on the driver's side and solid on the other side, what does this permit?

  1. Driving on the opposite side continuously
  2. Parking along the centre line
  3. Crossing to overtake when it is safe Correct answer.
  4. Never crossing the line at all

Explanation

Where the line nearest the driver is broken, the driver may cross it to overtake provided the road ahead is clear. The solid line on the other side restricts traffic coming the opposite way.

Question 15Traffic law, signs, signals and road markings

A heavy vehicle approaches a pedestrian crossing where people are waiting to cross. What must the driver do?

  1. Slow down and give way to pedestrians on or entering the crossing Correct answer.
  2. Maintain speed because the truck has right of way
  3. Swerve around the pedestrians
  4. Sound the horn so pedestrians wait

Explanation

Drivers must yield to pedestrians who are on a crossing or clearly about to use it, and heavy vehicles need extra braking distance so the approach should be slow. Horn use does not transfer the right of way to the truck.

Question 16Traffic law, signs, signals and road markings

What is indicated by a sign showing a red circle with a black truck inside and a red diagonal slash?

  1. A truck repair facility is nearby
  2. Goods vehicles are prohibited from entering Correct answer.
  3. A weighbridge is ahead
  4. Goods vehicles must use this route

Explanation

A red circle with a slash is a prohibition sign, and the vehicle silhouette inside identifies which class of traffic is banned. The sign therefore forbids goods vehicles from proceeding beyond that point.

Question 17Traffic law, signs, signals and road markings

At an uncontrolled T-junction with no signs or markings, which vehicle has priority?

  1. The vehicle that sounds its horn first
  2. The larger vehicle by reason of its size
  3. The vehicle emerging from the side road
  4. The vehicle on the through road continuing straight Correct answer.

Explanation

In the absence of signs or signals, traffic on the continuing road has priority and vehicles joining from the side road must yield. Vehicle size and horn use do not create a right of way.

Question 18Traffic law, signs, signals and road markings

What does a broken yellow line along the edge of the carriageway usually mark?

  1. A lane reserved for motorcycles
  2. The centre of a two-way road
  3. A restriction on stopping or parking at certain times Correct answer.
  4. A pedestrian-only zone

Explanation

Edge lines in yellow are used to control stopping and parking rather than to divide opposing traffic, and a broken pattern typically signals a time-limited restriction. The centre of the road is marked by white lines.

Question 19Traffic law, signs, signals and road markings

When may a driver lawfully use hazard warning lights on a heavy vehicle?

  1. When the vehicle is stationary and obstructing traffic or in an emergency Correct answer.
  2. Whenever the vehicle is reversing
  3. When parking illegally for a short time
  4. While driving normally in heavy rain

Explanation

Hazard lights warn other road users that the vehicle is a temporary obstruction or is in distress, such as when broken down. They are not a licence to park illegally, and they should not be left on while driving normally.

Question 20Traffic law, signs, signals and road markings

A traffic light shows a steady amber (yellow) signal as a truck approaches. What should the driver do?

  1. Accelerate to clear the junction
  2. Stop unless it is unsafe to do so Correct answer.
  3. Reverse away from the junction
  4. Continue at the same speed regardless

Explanation

A steady amber light warns that red is about to follow, so the driver should stop before the line unless stopping abruptly would cause a collision. A loaded truck needs a longer braking distance, so the decision must be made early.

Question 21Traffic law, signs, signals and road markings

Which behaviour constitutes driving under the influence under Cambodian traffic law?

  1. Driving after a full night's sleep
  2. Driving while using a hands-free device
  3. Driving with a passenger in the cab
  4. Operating a vehicle after consuming alcohol above the permitted limit Correct answer.

Explanation

Driving with a blood alcohol concentration above the legal limit is an offence, and the limit is stricter for professional and heavy vehicle drivers. Fatigue, passengers and hands-free equipment are separate issues from alcohol impairment.

Question 22Traffic law, signs, signals and road markings

A truck carrying an oversized load must travel on a public road. What is normally required before the journey?

  1. A special permit authorising the movement Correct answer.
  2. No formality if the load is tied down
  3. Written consent from other road users
  4. A police escort paid for by the driver

Explanation

Oversized or overweight loads require prior authorisation from the competent road authority, which may impose conditions such as route, time and escort. Securing the load is necessary but does not replace the permit.

Question 23Traffic law, signs, signals and road markings

What is the meaning of a sign showing a red circle with two black arrows, one pointing up and one pointing down, separated by a vertical bar?

  1. Overtaking is compulsory
  2. No entry for vehicles in the direction shown Correct answer.
  3. A dual carriageway begins
  4. Two-way traffic ahead

Explanation

This regulatory sign prohibits entry for traffic approaching from the direction indicated, commonly placed at the exit of a one-way street. Warning of two-way traffic uses a triangular sign with opposing arrows.

Question 24Traffic law, signs, signals and road markings

Before changing lanes on a multi-lane highway, a heavy vehicle driver should do which of the following?

  1. Rely on other drivers to make room
  2. Signal only after the lane change is complete
  3. Change lanes without signalling if the road is empty
  4. Check mirrors and blind spots and signal before moving Correct answer.

Explanation

A lane change requires the driver to check mirrors and blind spots, signal the intention in good time and ensure the new lane is clear. Heavy vehicles have large blind spots, so a shoulder check is especially important.

Question 25Traffic law, signs, signals and road markings

A driver sees a sign with a black cross inside a red-bordered triangle. What hazard does it warn of?

  1. A hospital zone ahead
  2. A railway crossing with barriers
  3. A crossroads or intersection ahead Correct answer.
  4. A no-stopping zone ahead

Explanation

A triangular sign with a cross warns that a road junction or crossroads lies ahead, so the driver should prepare to give way. A railway crossing uses a different symbol, such as a train or barrier image.

Question 26Traffic law, signs, signals and road markings

Under Cambodian traffic law, what does a police officer's hand signal take precedence over when directing traffic at an intersection?

  1. Only the road markings, but not the traffic lights
  2. Nothing, because signals only advise drivers
  3. Only the traffic lights, but not the road markings
  4. Traffic light colours and painted road markings Correct answer.

Explanation

A police officer controlling an intersection has authority over all fixed controls, so both signal lights and road markings must yield to the officer's directions. Drivers must obey the officer even when the light shows green. This rule exists so that traffic can be managed safely during incidents, congestion, or power failures.

Question 27Traffic law, signs, signals and road markings

A heavy truck driver sees a circular sign with a blue background and a white bicycle symbol. What does this sign require of the truck driver?

  1. A bicycle race is in progress and traffic must stop
  2. The route ahead is reserved for bicycles and the truck must not enter Correct answer.
  3. Bicycles must give way to motor vehicles on this road
  4. Bicycles are prohibited from the road ahead

Explanation

Blue circular signs in Cambodia indicate a mandatory instruction or a reserved facility. A blue circle with a bicycle means the lane or path is designated for cyclists, so motor vehicles such as trucks must stay out. The sign does not ban bicycles or announce an event.

Question 28Traffic law, signs, signals and road markings

A truck driver approaches a stop line painted across the lane together with an octagonal red sign. What is the correct action?

  1. Stop only if another vehicle is approaching
  2. Slow down and continue if no other vehicle is visible
  3. Sound the horn and proceed without stopping
  4. Come to a complete stop at the line and proceed only when the way is clear Correct answer.

Explanation

The octagonal red sign is the stop sign, and the painted line marks where the vehicle must halt. A full stop is required every time, regardless of whether traffic is visible, and the driver may then proceed only when it is safe. Rolling slowly past the line does not satisfy the requirement.

Question 29Traffic law, signs, signals and road markings

What does a solid white line painted along the left edge of a carriageway indicate to a heavy vehicle driver?

  1. A lane reserved for overtaking slower vehicles
  2. A place where parking is permitted at any time
  3. The edge of the carriageway, beyond which the vehicle should not normally travel Correct answer.
  4. The centre of the road for two-way traffic

Explanation

Edge lines mark the boundary of the usable carriageway and help drivers, especially of wide heavy vehicles, keep their position. Driving beyond the edge line onto the shoulder is not normal practice and is only acceptable in an emergency. The line does not create an overtaking lane or a parking bay.

Question 30Traffic law, signs, signals and road markings

A truck driver intends to turn right at a junction where a traffic light shows a green circle but a red arrow points right. What must the driver do?

  1. Turn right after sounding the horn
  2. Turn right immediately because the circular light is green
  3. Wait until the right-turn arrow turns green before turning Correct answer.
  4. Turn right only if no police officer is present

Explanation

A red arrow applies specifically to the movement it indicates, even when the general circular signal is green. The driver may proceed straight or turn left if those movements are permitted, but must wait for the right-turn arrow to change. The arrow controls that movement independently of the main light.

Question 31Traffic law, signs, signals and road markings

A heavy vehicle is carrying a load that projects beyond the rear of the vehicle. What does Cambodian traffic law require regarding the load?

  1. It must be marked so that other road users can see the projection, especially at night Correct answer.
  2. No marking is needed as long as the load is tied down
  3. The vehicle may only travel during daylight hours
  4. The driver must sound the horn continuously while moving

Explanation

Projecting loads create a hazard because following drivers may misjudge the vehicle's length, so the overhang must be made visible, typically with a flag or reflective marker. The requirement is about warning other road users rather than about the time of day. Securing the load alone does not satisfy the marking duty.

Question 32Traffic law, signs, signals and road markings

A truck is descending a steep hill and the driver sees a sign warning of a steep descent ahead. Which driving technique is most appropriate for a heavy vehicle?

  1. Keep the clutch depressed to coast down the slope
  2. Shift to neutral and rely on the footbrake for the whole descent
  3. Select a low gear before the descent and use engine braking to control speed Correct answer.
  4. Accelerate to clear the descent as quickly as possible

Explanation

Heavy vehicles can lose brake effectiveness through overheating if the footbrake is used continuously on a long descent. Selecting a low gear before the slope begins lets engine braking hold the speed steady. Coasting in neutral or with the clutch down removes engine braking and is dangerous.

Question 33Traffic law, signs, signals and road markings

On a road with a broken white centre line, a truck driver wishes to cross it to pass a slower vehicle. Which statement describes the legal position?

  1. Crossing is prohibited at all times on any road with a centre line
  2. Crossing is permitted only for vehicles under a certain weight
  3. Crossing is permitted only when the slower vehicle signals to the right
  4. Crossing is permitted when it is safe and visibility allows the manoeuvre to be completed Correct answer.

Explanation

A broken centre line indicates that vehicles may cross it to overtake when conditions are safe. The driver must still ensure clear visibility and enough road to complete the pass without endangering others. The line does not carry weight-based restrictions or depend on the other driver's signals.

Question 34Traffic law, signs, signals and road markings

A truck driver is approaching a junction and sees a triangular sign showing a black symbol of two children. What should the driver expect and do?

  1. Expect a cycle lane crossing the road ahead
  2. Expect children near a school or playground and reduce speed with readiness to stop Correct answer.
  3. Expect roadworks with children working on the site
  4. Expect a pedestrian-only zone where trucks are banned

Explanation

A red-bordered triangle with children warns of a school or playground where children may enter the road unpredictably. The correct response is to slow down and be ready to stop, since children often misjudge approaching traffic. The sign does not ban trucks or indicate roadworks.

Question 35Traffic law, signs, signals and road markings

A heavy truck must cross a narrow bridge marked with a weight limit sign lower than the truck's permitted gross weight. What is the correct course of action?

  1. Do not cross the bridge and find an alternative route Correct answer.
  2. Cross only when no other vehicle is on the bridge
  3. Cross slowly to reduce the load on the structure
  4. Reduce tyre pressure and then cross

Explanation

A weight limit sign states the maximum load the structure can safely carry, and a vehicle above that limit must not cross even if it moves slowly. The restriction protects the bridge from structural failure, which could injure the driver and others. An alternative route is the only lawful option.

Question 36Traffic law, signs, signals and road markings

At night, a truck driver is following another vehicle on an unlit road. How should the headlights be used?

  1. Use hazard warning lights instead of headlights
  2. Switch to dipped beam so the driver ahead is not dazzled through the mirrors Correct answer.
  3. Turn the headlights off and rely on the vehicle ahead's lights
  4. Keep full beam on to see as far ahead as possible

Explanation

Full beam directed at the rear of a vehicle ahead is reflected in the mirrors and dazzles that driver. Dipped beam gives adequate forward vision without blinding others. Headlights must remain on at night, and hazard lights are not a substitute for them.

Question 37Traffic law, signs, signals and road markings

A truck driver sees a circular sign with a red border and a black diagonal slash through a symbol of a horn. What does this mean?

  1. The horn is defective and must be repaired
  2. Sounding the horn is prohibited in this area Correct answer.
  3. The horn must be sounded to warn pedestrians
  4. Only heavy vehicles may sound their horn here

Explanation

A red-bordered circle with a diagonal slash is a prohibition sign, so the horn symbol with a slash bans horn use in that area, typically near hospitals or schools. The driver must comply even if traffic is slow. The sign does not require horn use or relate to vehicle maintenance.

Question 38Traffic law, signs, signals and road markings

A truck driver is directed by a police officer to proceed through an intersection while the traffic light is red. What is the driver's legal obligation?

  1. Remain stopped until the light turns green
  2. Obey the officer and proceed carefully through the intersection Correct answer.
  3. Refuse to move because the red light always prevails
  4. Proceed only after the officer has left the scene

Explanation

When an officer is controlling traffic, the officer's instructions replace the fixed signals. The driver should follow the direction while still checking that the path is clear. Treating the red light as absolute in this situation would obstruct the officer's management of traffic.

Question 39Traffic law, signs, signals and road markings

A truck driver is on a road with two lanes in the same direction and the right lane is marked with a white arrow curving right at the junction ahead. What does this lane marking require?

  1. Vehicles in that lane must turn right at the junction Correct answer.
  2. Vehicles in that lane must continue straight ahead
  3. Vehicles in that lane must stop before the junction
  4. Vehicles in that lane may turn right or go straight

Explanation

Directional arrows painted in a lane prescribe the movement for vehicles using that lane. A right-curving arrow means traffic in that lane must turn right and cannot continue straight. Drivers who intend to go straight must choose a lane marked for that movement.

Question 40Traffic law, signs, signals and road markings

A truck driver is overtaking a cyclist on a narrow road when a solid white line appears on the driver's side of the centre markings. What is the safest and lawful response?

  1. Sound the horn and continue alongside the cyclist
  2. Complete the overtake quickly before the solid line begins
  3. Abandon or delay the overtake and return behind the cyclist until the line permits passing Correct answer.
  4. Move fully into the opposing lane to give the cyclist room

Explanation

A solid line on the driver's side prohibits crossing the centre of the road, so an overtake that requires crossing it is not lawful. The driver should hold back at a safe distance until the markings allow a proper pass with adequate clearance. Rushing the manoeuvre or entering the opposing lane increases the risk of a head-on collision.

Question 41Vehicle inspection, maintenance and load security

Before starting a loaded heavy truck, the driver must check the air pressure gauge. What minimum reading should the gauge show before the vehicle is safe to drive?

  1. Any reading above zero is acceptable because the compressor builds pressure while driving.
  2. The pressure must be at the manufacturer's specified minimum, typically around 690 kPa (100 psi), with the low-pressure warning buzzer off. Correct answer.
  3. The gauge only needs to show pressure after the engine has been running for ten minutes.
  4. The reading is irrelevant on flat roads because the brakes are hydraulic.

Explanation

Air-braked heavy vehicles need full reservoir pressure before moving, because the spring brakes and service brakes depend on it. The manufacturer's minimum, often near 690 kPa (100 psi), must be reached and the low-pressure warning must be off. Waiting for the compressor to build pressure while driving is unsafe because braking performance is reduced.

Question 42Vehicle inspection, maintenance and load security

During a pre-trip walk-around, you notice one rear tyre has a deep cut exposing the cord. What is the correct action?

  1. Replace the tyre or switch to the spare before the vehicle moves. Correct answer.
  2. Reduce speed and continue the trip, monitoring the tyre at each stop.
  3. Cover the cut with tape so it does not spread.
  4. Inflate the tyre to maximum pressure to hold the cord in place.

Explanation

A cut that exposes the cord means the tyre's structural integrity is compromised and it can fail suddenly under load. The vehicle must not be driven until that wheel is fitted with a sound tyre, such as the spare. Cosmetic fixes or pressure changes do not restore strength to damaged casing.

Question 43Vehicle inspection, maintenance and load security

What is the main purpose of the daily check for oil and coolant levels on a heavy vehicle?

  1. To keep the engine bay clean of dust.
  2. To detect leaks or consumption problems before they cause engine damage or breakdown. Correct answer.
  3. To satisfy paperwork requirements for the transport company.
  4. To improve fuel economy on long routes.

Explanation

Fluid checks catch low levels and leaks early, before overheating or lubrication failure causes costly engine damage or a roadside breakdown. They are a preventive maintenance step, not a fuel-saving or cleaning measure. Catching a slow leak also prevents sudden loss of coolant or oil on the road.

Question 44Vehicle inspection, maintenance and load security

A cargo of bagged rice is loaded in a truck. Which method best prevents the load from shifting forward during heavy braking?

  1. Placing a single rope over the top of the load.
  2. Leaving the load loose so it settles naturally.
  3. Stacking the bags as high as possible against the tailgate.
  4. Using load restraints and blocking so the load is secured against movement in all directions. Correct answer.

Explanation

Load security requires restraints and blocking that prevent movement forward, backward and sideways, including under braking and cornering forces. A properly restrained load cannot slide into the cab or off the sides. Height and loose stowage increase the risk of shifting.

Question 45Vehicle inspection, maintenance and load security

When should a driver check that the load has not shifted during a journey?

  1. Only when a traffic officer asks.
  2. Only at the final destination.
  3. Once per week regardless of distance.
  4. At the start and at regular intervals or after any hard braking or rough road section. Correct answer.

Explanation

Loads can settle or shift after braking, cornering or rough surfaces, so restraints should be re-checked at planned intervals and after any event that could loosen them. Checking only at the end of the trip leaves the vehicle unsafe for most of the journey. Regular checks are part of the driver's responsibility for load security.

Question 46Vehicle inspection, maintenance and load security

What does the low air-pressure warning buzzer indicate on a heavy vehicle?

  1. That reservoir pressure has fallen below a safe level for braking. Correct answer.
  2. That the parking brake is fully released.
  3. That the engine oil is due for a change.
  4. That the load exceeds the permitted weight.

Explanation

The low-pressure warning sounds when air reservoir pressure drops below the safe operating threshold, warning that braking performance may be reduced. The driver should stop safely and let pressure build, or investigate a leak. It does not relate to parking brake status, oil changes or load weight.

Question 47Vehicle inspection, maintenance and load security

Which item is part of a correct pre-departure check of the truck's lighting?

  1. Relying on the dashboard warning lamp alone.
  2. Checking only the headlights because other lights are optional.
  3. Testing the lights only after dark.
  4. Confirming that headlights, brake lights, indicators and reflectors all work and are clean. Correct answer.

Explanation

All lamps and reflectors that make the vehicle visible and signal its intentions must work and be clean before departure. Brake lights and indicators are essential for other road users and are legally required. A dashboard lamp does not confirm that the bulbs at each corner are functioning.

Question 48Vehicle inspection, maintenance and load security

Why must the load be distributed evenly over the axles rather than concentrated at the rear?

  1. To reduce the number of restraints needed.
  2. To allow the driver to exceed the speed limit safely.
  3. To make the truck look level in photographs.
  4. To keep each axle within its rated load and maintain steering and braking balance. Correct answer.

Explanation

Axles have rated maximum loads, and concentrating weight at the rear can overload the rear axle while reducing grip on the steering axle. Even distribution keeps each axle within its rating and preserves steering and braking balance. Load position affects vehicle stability, not appearance or speed limits.

Question 49Vehicle inspection, maintenance and load security

A driver hears a rhythmic thumping from one wheel that increases with road speed. Which cause should be checked first?

  1. An out-of-balance or damaged tyre or wheel. Correct answer.
  2. A loose exhaust bracket.
  3. A worn windscreen wiper.
  4. A low coolant level.

Explanation

A speed-related rhythmic thump usually points to a tyre or wheel problem such as imbalance, a flat spot, a bulge or a loose wheel nut. These should be inspected immediately because a failing wheel can cause loss of control. Exhaust, coolant and wiper issues do not produce speed-related wheel noise.

Question 50Vehicle inspection, maintenance and load security

When coupling a trailer to a tractor unit, what confirms the fifth-wheel coupling is properly locked?

  1. The trailer lights illuminate when connected.
  2. The landing legs are still touching the ground.
  3. The driver hears any metallic sound during coupling.
  4. The trailer rests on the fifth wheel and the coupling handle is in the locked position with a visual check and a pull test. Correct answer.

Explanation

A secure coupling requires the kingpin to be fully engaged, the locking handle in its locked position, and a physical check such as a pull test before the landing legs are raised. Lights and sounds alone do not prove the kingpin is locked. An unlocked coupling can separate on the road.