Cameroon Heavy-Vehicle Theory key terms

A circular intersection where traffic already inside the ring has right-of-way over entering vehicles. In Cameroon, approach signs and road markings warn drivers to yield; heavy vehicles must often use the outer lane and signal exit clearly.

A regulatory sign or marking requiring a driver to slow down and give way to traffic on the intersecting road. Failing to yield is a common cause of collisions at junctions and roundabouts, especially for long vehicles.

A regulatory sign meaning the vehicle must come to a complete halt at the stop line or, if none, at the edge of the intersecting road, and give way before proceeding. Rolling stops are an offence and dangerous for heavy vehicles.

A solid white transverse line marking the exact point where a vehicle must stop at a Stop sign or traffic light. Drivers must not cross it while the signal is red or before yielding.

A red traffic light requiring all vehicles to stop before the stop line or pedestrian crossing. For heavy vehicles, braking distance is longer, so drivers must anticipate the change and avoid sudden stops.

An amber traffic light warning that the signal is about to turn red. Drivers should stop unless it is unsafe to do so; heavy vehicles need extra distance to stop safely, so approach speed must be controlled.

The default right-of-way rule at unmarked intersections: yield to vehicles approaching from your right. Heavy-vehicle drivers must scan carefully because their size can hide approaching traffic from view.

The act of overtaking another vehicle. For heavy vehicles, overtaking requires long clear sight distance and sufficient power; it is prohibited near crests, bends, pedestrian crossings, and where solid lines or signs forbid it.

A solid longitudinal road marking that must not be crossed or straddled. It often separates opposing traffic or marks a no-overtaking zone where visibility is limited, which is critical for slow heavy vehicles.

A broken longitudinal road marking that may be crossed when safe, for example to overtake or change lanes. Drivers must still signal, check mirrors and blind spots, and ensure the manoeuvre is legal and safe.

The minimum gap a driver should keep behind the vehicle ahead to allow safe braking. For heavy vehicles it must increase with speed, load, and wet roads; a common guide is at least two seconds in good conditions.

The distance a vehicle travels from the moment the brakes are applied until it stops. It increases with speed, mass, and poor grip, so a loaded lorry needs far more space than a car.

The delay between a hazard appearing and the driver applying the brakes. It is typically about one second but lengthens with fatigue, alcohol, or distraction, adding many metres to the total stopping distance of a heavy vehicle.

The maximum legally permitted total mass of a vehicle including its load, fuel, and occupants. Exceeding the PTAC is an offence and increases braking distance, tyre stress, and road damage.

The maximum permitted combined mass of a towing vehicle plus its trailer and all loads. It is used for articulated vehicles and drawbar combinations, and exceeding it risks prosecution and mechanical failure.

Carrying more weight than the vehicle's legal or design limit. It overloads tyres, brakes, and suspension, lengthens stopping distances, and is a serious offence that can lead to fines and immobilisation.

The way weight is distributed across a vehicle's axles and within the load space. Poor distribution can overload an axle, make steering light, or cause instability, so loads must be spread evenly and secured.

The securing of cargo using straps, chains, or other restraints so it cannot shift or fall during transport. Proper lashing is legally required and prevents load loss, rollover, and injury to other road users.

The maximum permitted dimensions of a vehicle, including length, width, and height. Drivers must know their vehicle's dimensions to avoid bridge strikes, lane encroachment, and route restrictions.

The clear height under a bridge, tunnel, or overhead structure, shown on warning signs. A driver must compare it with the vehicle's total height including load to avoid a collision.

Warning signs, usually triangular with a red border, that alert drivers to hazards ahead such as bends, steep hills, or narrow bridges. Heavy vehicles must reduce speed early because they cannot stop or swerve quickly.

A speed hump or raised section of road designed to slow traffic. Heavy vehicles should cross slowly to avoid suspension damage and load shift, and must watch for signs warning of them.

A braking effect produced by engine compression, often enhanced by an exhaust brake or retarder, used to control speed on long descents without overheating the service brakes. It reduces brake fade risk on heavy vehicles.

The main foot-operated braking system used to slow and stop the vehicle. On heavy vehicles it is often air-assisted; drivers must check air pressure and brake response during the pre-trip inspection.

A loss of braking efficiency caused by overheating, common on long downhill runs when brakes are used continuously. Drivers should use engine braking and lower gears, and stop to let brakes cool if they feel weak.

A periodic mandatory inspection of a vehicle's roadworthiness, covering brakes, lights, steering, tyres, and emissions. A valid certificate is required for heavy vehicles, and driving without one can lead to penalties.

Compulsory insurance covering third-party liability for death, injury, or property damage caused by the vehicle. Drivers must carry proof and ensure the policy is valid for the vehicle and its use.

The vehicle registration document that identifies the owner and the vehicle's technical details. A driver must be able to produce it during a roadside check, along with licence and insurance.

The driving licence authorising a person to drive a particular category of vehicle. Heavy lorries require the appropriate category, and driving without a valid licence is a serious offence.

Physical and mental tiredness that slows reactions, impairs judgement, and increases the risk of falling asleep at the wheel. Heavy-vehicle drivers must take regular breaks and respect driving-time limits.

The concentration of alcohol in the blood, measured to enforce drink-driving laws. Even small amounts impair coordination and judgement; professional drivers face strict limits and should not drink before driving.

Illegal drugs or substances that impair driving ability. Driving under their influence is prohibited, and drivers may be tested; heavy-vehicle operators face severe consequences because of the greater danger they pose.

A fuel-efficient driving style using smooth acceleration, early gear changes, anticipation, and steady speeds. It reduces fuel consumption, emissions, and wear, and is particularly valuable for high-mileage heavy vehicles.

The amount of fuel a vehicle uses over a given distance. It rises with aggressive driving, overloading, low tyre pressure, and poor maintenance, so monitoring it helps control costs and emissions.

Regular servicing and checks carried out before faults develop, such as oil changes, brake adjustments, and tyre inspections. It improves safety, fuel efficiency, and reliability, and reduces breakdowns on the road.

A systematic pre-trip inspection of tyres, brakes, lights, fluids, load security, and mirrors before driving. It helps detect defects early and is a legal and professional duty for heavy-vehicle drivers.

An area around the vehicle that the driver cannot see directly or through mirrors. Heavy vehicles have large blind spots, so drivers must check carefully and use mirrors and aids before turning or changing lanes.

A driving approach that anticipates hazards and the mistakes of others, keeping a safe margin and being ready to react. It is essential for heavy-vehicle drivers because of their limited manoeuvrability and long stopping distances.

Immediate basic care given to an injured person before professional help arrives, such as controlling bleeding, keeping the airway open, and not moving a suspected spinal injury. Every driver should know the emergency number.

A collision or other incident involving a vehicle that causes injury or damage. Drivers must stop, secure the scene, warn other traffic, assist casualties, and report to the authorities as required by law.