Take AF Commercial Driving Theory Practice Questions - Afghanistan Driving License Theory Test - Commercial & Heavy Vehicle Exam

QUESTION 1 / 25

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

Choose one answer below.

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

QUESTION 2 / 25

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

Choose one answer below.

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✓

QUESTION 3 / 25

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

Choose one answer below.

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✓

QUESTION 4 / 25

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

Choose one answer below.

AWater and oil sludge can freeze in cold weather, block valves, corrode components, and cause brake failure✓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✓

QUESTION 5 / 25

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

Choose one answer below.

AThe powerful mechanical spring parking brakes (maxi brakes) automatically engage and lock the rear wheels✓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✓

QUESTION 6 / 25

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

Choose one answer below.

AThe rear wheels of the trailer follow a shorter path and track inside the turning radius of the front steering wheels✓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✓

QUESTION 7 / 25

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

Choose one answer below.

AKeep the rear of the vehicle close to the right curb initially and swing wide into the intersection (button-hook turn) only as you complete the turn✓BSwing wide to the left before beginning the turn (jug-handle turn), leaving a wide open gap on your right for cars to squeeze in✓CCut the corner as tightly as possible across the pedestrian sidewalk✓DTurn from the extreme left lane without looking at right mirrors✓

QUESTION 8 / 25

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

Choose one answer below.

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

QUESTION 9 / 25

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

Choose one answer below.

ALevel the load below the sideboards and cover completely with a securely fastened tarpaulin (tarp)✓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✓

QUESTION 10 / 25

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

Choose one answer below.

AThe total maximum legal weight of the fully loaded vehicle, including chassis, body, fuel, driver, and cargo✓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✓

QUESTION 11 / 25

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

Choose one answer below.

ASignificantly longer braking distances, increased risk of brake failure, tire blowouts, severe road/bridge damage, and high rollover probability✓BImproved fuel efficiency and smoother hill climbing✓CIncreased vehicle top speed on downhills✓DLower center of gravity and increased stability✓

QUESTION 12 / 25

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

Choose one answer below.

AIt lightens the tractor's drive axles, reducing traction and steering control while increasing the risk of trailer sway (fishtailing)✓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✓

QUESTION 13 / 25

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

Choose one answer below.

AAn engine braking system that converts the engine into an air compressor to slow the vehicle on long downhill grades without heating the wheel brakes✓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✓

QUESTION 14 / 25

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

Choose one answer below.

AOn slippery, icy, wet, or snow-covered road surfaces to prevent the drive wheels from locking and causing an immediate jackknife✓BOn dry asphalt highways on sunny days✓CWhen descending steep mountain passes in dry weather✓DWhen fully loaded with heavy cargo✓

QUESTION 15 / 25

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?

Choose one answer below.

AObtain a special permit issued by the traffic administration before the vehicle uses public roads✓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✓

QUESTION 16 / 25

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

Choose one answer below.

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✓

QUESTION 17 / 25

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

Choose one answer below.

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✓

QUESTION 18 / 25

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

Choose one answer below.

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

QUESTION 19 / 25

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

Choose one answer below.

AThe fifth-wheel locking jaws are closed completely around the shank of the kingpin and the safety release handle is locked✓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✓

QUESTION 20 / 25

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

Choose one answer below.

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

QUESTION 21 / 25

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

Choose one answer below.

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

QUESTION 22 / 25

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

Choose one answer below.

AThe tractor's drive wheels lock up or lose traction on a slippery road, causing the heavy trailer to push the tractor sideways into a V-shape✓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✓

QUESTION 23 / 25

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

Choose one answer below.

ARelease the service brakes immediately to allow the drive wheels to regain rolling traction, and countersteer in the direction of the skid✓BApply maximum emergency foot brake force✓CPull the trailer hand valve (trolley brake) down hard✓DAccelerate to top speed in low gear✓

QUESTION 24 / 25

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

Choose one answer below.

AStanding passengers are strictly prohibited on intercity mountain highways; all passengers must occupy designated seats✓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✓

QUESTION 25 / 25

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

Choose one answer below.

AAt least 4 to 6 seconds of travel time (plus 1 additional second for every 15 km/h above 60 km/h)✓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✓