Afghanistan Driving License Theory Test — Commercial & Heavy Vehicle

What is the primary function of the air compressor in a heavy commercial vehicle's pneumatic brake system?

• ATo pump compressed air into the storage reservoirs (air tanks) to supply the braking syst…
• BTo cool the engine cylinders during heavy braking
• CTo provide hydraulic fluid pressure to the clutch
• DTo inflate the cabin air conditioning system

At approximately what pressure does the air compressor governor typically cut out (stop pumping air into the tanks)?

• AAround 120 to 125 PSI (approximately 8.3 to 8.6 bar)
• BAround 40 to 50 PSI
• CAround 250 to 300 PSI
• DAround 10 to 15 PSI

At what air pressure must the low air pressure warning device (buzzer or red light) activate in a commercial air brake vehicle?

• ABefore air pressure drops below approximately 60 PSI (around 4.1 bar)
• BOnly when air pressure reaches 0 PSI
• CAt 100 PSI
• DOnly when the vehicle comes to a complete halt

Why must air brake storage tanks be drained daily of water and oil accumulation?

• AWater and oil sludge can freeze in cold weather, block valves, corrode components, and ca…
• BTo reduce vehicle total weight for fuel economy
• CTo allow fresh fuel to enter the air brake lines
• DDraining tanks is only required once every 5 years during major overhauls

What happens when air pressure in a heavy vehicle's pneumatic system drops completely to zero while driving?

• AThe powerful mechanical spring parking brakes (maxi brakes) automatically engage and lock…
• BThe brakes release completely, leaving the vehicle to coast with no retardation
• CThe service brakes continue to work normally from a reserve air supply
• DThe engine shuts down automatically and the vehicle rolls to a halt

What is 'off-tracking' (swept path) in a long semi-trailer or articulated truck?

• AThe rear wheels of the trailer follow a shorter path and track inside the turning radius…
• BThe trailer slides sideways off the road on ice
• CThe truck leaves paved highway to drive on dirt tracks
• DThe steering wheels turn in the opposite direction of the steering column

When making a sharp right turn with a long articulated truck at a narrow city intersection, how should you position your vehicle?

• AKeep the rear of the vehicle close to the right curb initially and swing wide into the in…
• BSwing wide to the left before beginning the turn (jug-handle turn), leaving a wide open g…
• CCut the corner as tightly as possible across the pedestrian sidewalk
• DTurn from the extreme left lane without looking at right mirrors

Where are the primary 'No-Zones' (large blind spots) located around a heavy commercial truck or bus?

• ADirectly in front, directly behind the trailer, and along both sides (especially the righ…
• BOnly directly underneath the engine compartment
• COnly in the driver's left-side mirror
• DHeavy trucks with panoramic mirrors have zero blind spots

What is the proper method for securing loose bulk cargo (such as sand, gravel, or soil) in an open-top dump truck?

• ALevel the load below the sideboards and cover completely with a securely fastened tarpaul…
• BPile the aggregate as high as possible in a pyramid shape without covering
• CWet the surface with water so wind cannot blow particles away
• DDrive faster so aggregate settles into the truck bed

What is Gross Vehicle Mass (GVM) / Gross Vehicle Weight (GVW)?

• AThe total maximum legal weight of the fully loaded vehicle, including chassis, body, fuel…
• BThe weight of the empty vehicle with zero cargo or fuel
• CThe weight of the cargo alone
• DThe maximum weight allowed on the front steering axle only

What are the major safety hazards of overloading a commercial heavy truck beyond its legal axle limits?

• ASignificantly longer braking distances, increased risk of brake failure, tire blowouts, s…
• BImproved fuel efficiency and smoother hill climbing
• CIncreased vehicle top speed on downhills
• DLower center of gravity and increased stability

How does distributing cargo weight too far toward the rear of a semi-trailer affect vehicle handling?

• AIt lightens the tractor's drive axles, reducing traction and steering control while incre…
• BIt makes the front steering wheels too heavy to turn
• CIt increases braking power on the front steering axle
• DIt eliminates the need for tie-down straps

What is an auxiliary engine compression brake (such as a Jake brake or retarder), and when should it be used?

• AAn engine braking system that converts the engine into an air compressor to slow the vehi…
• BA device that pumps additional air into the reservoirs during a descent
• CA gearbox setting that increases pulling power on steep climbs
• DA full replacement for the service foot brake in heavy city traffic

Under what road condition should an engine retarder or exhaust brake be turned OFF or set to low power?

• AOn slippery, icy, wet, or snow-covered road surfaces to prevent the drive wheels from loc…
• BOn dry asphalt highways on sunny days
• CWhen descending steep mountain passes in dry weather
• DWhen fully loaded with heavy cargo

Under the Road Traffic Law, what must the operator of a vehicle do if its weight or dimensions exceed the maximum figures fixed by law?

• AObtain a special permit issued by the traffic administration before the vehicle uses publ…
• BNothing, provided the load is covered by a tarpaulin
• CNothing, provided the vehicle travels only at night
• DNotify the municipality after the journey has been completed

Afghan driving licences are issued in five grades. Which grade covers goods vehicles (lorries) with a total weight above 3,500 kg?

• AGrade 3, also shown as category C
• BGrade 4, also shown as category B
• CGrade 5, also shown as category A
• DGrade 2, also shown as category D

What are the two pneumatic air lines that connect a tractor truck to a semi-trailer?

• AThe Emergency/Supply line (usually red) and the Service line (usually blue)
• BThe Fuel feed line and the Coolant line
• CThe Turbo boost line and the Exhaust return line
• DThe Air conditioning line and the Horn line

What happens if the red emergency air line between tractor and trailer ruptures or becomes disconnected while driving?

• ATrailer air pressure escapes instantly, and the trailer emergency spring brakes lock up a…
• BThe trailer begins coasting freely without brakes
• CThe tractor engine shuts off immediately
• DThe trailer electrical lights become brighter

During fifth-wheel coupling inspection, what must you visually verify under the trailer before driving?

• AThe fifth-wheel locking jaws are closed completely around the shank of the kingpin and th…
• BThere is a 5 cm gap between the upper coupler plate and fifth wheel skid plate
• CThe kingpin is resting loosely on top of the fifth wheel plate
• DThe landing gear legs are touching the ground with weight on them

What is the primary danger of operating a commercial vehicle with dual tires when one of the tires is completely flat?

• AThe remaining tire bears double load, overheating rapidly and catching fire, or throwing…
• BThe vehicle fuel tank will leak automatically
• CThe truck cannot turn left
• DThe engine cooling fan stops rotating

What is a 'runaway truck ramp' (emergency escape lane) on steep mountain passes, and when should a truck driver use it?

• AA dedicated uphill bed of deep gravel or sand designed to stop runaway heavy vehicles exp…
• BA VIP overtaking lane for high-speed buses
• CA scenic rest area for overnight camping
• DA weighing station for overloaded agricultural trucks

What is a 'trailer jackknife' and what causes it?

• AThe tractor's drive wheels lock up or lose traction on a slippery road, causing the heavy…
• BThe front tires blowout causing the truck to flip backwards
• CThe landing gear drops down while driving at high speed
• DThe steering wheel locks when turning a corner

What is the first action a commercial driver should take to recover from an impending trailer jackknife skid?

• ARelease the service brakes immediately to allow the drive wheels to regain rolling tracti…
• BApply maximum emergency foot brake force
• CPull the trailer hand valve (trolley brake) down hard
• DAccelerate to top speed in low gear

What should a commercial bus driver ensure regarding standing passengers on intercity long-distance routes in Afghanistan?

• AStanding passengers are strictly prohibited on intercity mountain highways; all passenger…
• BPassengers may stand in the aisle as long as they hold onto luggage racks
• CStanding passengers are permitted up to twice the seating capacity
• DPassengers may sit on the roof of the bus if the interior is full

What is the mandatory minimum following distance behind other vehicles for a heavy commercial truck under good road conditions?

• AAt least 4 to 6 seconds of travel time (plus 1 additional second for every 15 km/h above…
• B1 second regardless of vehicle weight
• C5 metres behind the vehicle in front
• DHeavy trucks have shorter stopping distances and require less gap than passenger cars

When transporting hazardous materials (HAZMAT) / Dangerous Goods, what documentation must the commercial driver carry in the cab?

• AOfficial Dangerous Goods transport manifest / shipping papers, Material Safety Data Sheet…
• BOnly the driver's national Tazkira ID card
• CCommercial marketing brochures of the chemical company
• DNo paperwork is required if the truck displays warning placards

What diamond-shaped placard displaying a red background with a flame symbol and the number '3' at the bottom indicates:

• AClass 3 Flammable Liquid (such as petrol, diesel, or kerosene)
• BClass 1 Explosives
• CClass 7 Radioactive materials
• DNon-flammable compressed gas

What should a truck driver do before reversing a heavy articulated vehicle into a loading bay?

• AGet out and look (GOAL), inspect overhead and ground clearances, turn on 4-way hazard fla…
• BReverse as fast as possible while sounding the air horn continuously
• CRely entirely on the left side mirror without looking at the right side
• DDisconnect the trailer brake air hoses before reversing

Why is it dangerous to rapidly fan (pump) the foot brake pedal repeatedly on an air brake equipped truck?

• AFanning the brake pedal releases large volumes of compressed air faster than the compress…
• BIt causes engine oil to leak into the fuel tank
• CIt causes the steering wheel to vibrate and turn automatically
• DIt increases braking force to dangerous levels

What is the proper gear selection rule before descending a long, steep mountain pass (such as Salang Pass) in a heavy loaded truck?

• AShift into a low gear that allows the engine compression to control speed before starting…
• BStay in top high gear to keep engine RPM low
• CPlace the transmission into neutral and rely on the foot brakes
• DTurn off the engine ignition key to save fuel

What is the primary function of a safety relief valve installed in an air brake reservoir?

• ATo automatically vent excess air pressure if the governor fails, preventing the air tanks…
• BTo hold the reservoir at a constant pressure by bleeding air continuously while driving
• CTo drain accumulated water from the reservoir automatically at each stop
• DTo cut the compressor out once the reservoirs reach working pressure

What is 'brake lag distance' in an air brake system?

• AThe distance the vehicle travels between pressing the brake pedal and the moment compress…
• BThe distance required to replace worn brake pads
• CThe length of the air hoses between tractor and trailer
• DThe delay in releasing the parking brake lever

How often should commercial heavy vehicle drivers perform a walkaround pre-trip safety inspection?

• ABefore every single driving shift and trip
• BOnce every six months
• COnly when the vehicle fails an annual government inspection
• DOnly after an accident has occurred

What is the minimum legal tread depth required for steering axle (front) tires on a heavy commercial vehicle?

• AAt least 3.2 mm (or 4/32 inch) in major tread grooves
• B0.5 mm
• C10.0 cm
• DSteering tires are permitted to be completely bald if drive tires have good tread

Why are recapped (retreaded) or regrooved tires strictly prohibited from being installed on the front steering axle of heavy commercial trucks?

• ARetread separation or delamination on a front steering tire causes immediate, violent los…
• BRecapped tires are too light for the engine weight
• CRecapped tires drain power from the alternator
• DRecapped tires can only be used on non-motorized horse carts

What is the minimum number of heavy-duty tie-down straps required to secure an item of heavy cargo on a flatbed trailer?

• AAt least two tie-downs for any cargo piece over 1.5 metres in length, with additional tie…
• BOne thin rope regardless of cargo weight
• CCargo requires tie-downs only if it weighs more than 20 tonnes
• DNo tie-downs are needed if the flatbed has side rails

What is the purpose of a headerboard (bulkhead) on the front of a flatbed trailer?

• ATo prevent forward-shifting cargo from penetrating the driver's cab during sudden emergen…
• BTo improve aerodynamic airflow over the cargo
• CTo display company advertising signs
• DTo provide a sleeping platform for co-drivers

What is 'liquid surge' in a tanker truck carrying liquid cargo (such as water, milk, or fuel)?

• AThe forward and backward or lateral movement of liquid within an unbaffled or partially f…
• BLiquid boiling inside the tank due to engine exhaust heat
• CExcessive fuel consumption in tanker trucks
• DHydraulic pressure buildup inside the brake lines

How should a tanker driver handle curves when hauling a partially full liquid tanker?

• ASlow down well before entering the curve, maintain a smooth steady arc, and avoid sudden…
• BAccelerate into the curve to force the liquid against the outer tank wall
• CBrake hard in the middle of the curve to stabilize the liquid
• DDrive on the extreme outer shoulder of the curve

What is the primary danger when driving an empty semi-trailer (bobtail tractor or empty flatbed) compared to a fully loaded truck?

• ALight weight provides less tire friction, causing wheel lockup, bouncing, extended brakin…
• BThe truck cannot climb hills when empty
• CThe engine overheats because there is no cargo to absorb heat
• DEmpty trailers cannot be steered around corners

What is a 'bobtail' tractor, and how does it handle during emergency braking?

• AA tractor operating without a semi-trailer attached; it is light in the rear and takes lo…
• BA truck with two steering axles
• CA bus converted for freight hauling
• DA truck that operates on electric battery power only

What safety equipment must all commercial passenger buses in Afghanistan carry by law?

• AFunctional fire extinguishers (minimum Class ABC), first aid kits, emergency window break…
• BOnly a spare tire
• COnly an extra set of passenger seats
• DCommercial buses are exempt from safety equipment mandates

What is the correct procedure for testing the air brake leakage rate during a pre-trip inspection?

• AShut off the engine with full air pressure, release parking brakes, hold down the foot br…
• BPump the brake pedal 50 times with engine running at maximum RPM
• CTurn off the air compressor and drive for 10 kilometres
• DListen for leaks while playing the radio at high volume

What does excessive travel (free play) on an S-cam brake slack adjuster indicate?

• AThe brake shoes are worn or out of adjustment, resulting in delayed braking and severe lo…
• BThe brake shoes are brand new and functioning perfectly
• CThe air compressor is pumping too much air
• DThe tires are over-inflated

What is the primary risk when driving a high-sided box truck or empty enclosed trailer across elevated mountain bridges or windy mountain valleys?

• AStrong lateral wind gusts can push the truck out of its lane or tip the vehicle over onto…
• BWind will blow fuel out of the fuel tank filler neck
• CWind will detach the headlights from the front bumper
• DWind will stall the diesel engine fuel injection pump

What should a commercial truck driver do if a front steering tire blows out at 70 km/h?

• AFirmly grip the steering wheel with both hands to maintain direction, stay off the brake…
• BSlam on the foot brakes with maximum force immediately
• CPull the trailer emergency air valve instantly
• DTurn the steering wheel hard in the opposite direction of the blowout

The Road Traffic Law classifies traffic accidents into three groups. What determines which group an accident falls into?

• AThe severity of injury caused and the value of the financial loss
• BThe number of vehicles involved in the collision
• CWhether the accident happened inside or outside a city
• DThe engine capacity of the largest vehicle involved