Doha General Directorate of Traffic - Qatar Heavy Vehicle Skills Test 1

Q: How many questions is the Doha General Directorate of Traffic truck & bus theory test?

The official General Directorate of Traffic truck & bus theory test in Doha has 40 questions and you need 37 correct (92.5%) to pass. This practice test has 22 questions.

Q: Is this the real exam?

These are practice questions to help you revise, written to the published rules and to what candidates report from the real test. They are not the official Qatar exam and the real question bank, format, fees and pass mark are set by the General Directorate of Traffic (Ministry of Interior) and the driving schools, and can change. Always confirm the current requirements with your driving school or the traffic department (for example via the Metrash service).

Q: Is this practice test free?

The first 10 questions are free, with no signup, and each shows the answer and the reason. The full 22-question test, timed, is in the Qatar Driving Theory Online Practice Bank (QAR 39, one payment), with every question in the bank.

Q: What does the Doha truck & bus theory test cover?

Road signs, traffic signals, right of way, roundabouts, speed limits, seat belts, penalties and safe-driving rules, plus the handling and safety topics specific to your vehicle.

Question 1

Why does a fully loaded heavy truck need a much longer stopping distance than a car travelling at the same speed?

Accepted Answer

Greater mass means greater kinetic energy, so more distance is needed to dissipate that energy through braking. A fully loaded truck requires a much longer stopping distance because its greater mass means far more kinetic energy must be absorbed. Even with powerful brakes, physics demands more distance to bring that energy to zero. Always increase your following distance significantly when loaded.

Answer

Heavy trucks have weaker brakes that are not designed for fast stops

Answer

The larger tyres create less friction with the road surface

Answer

Heavy trucks must follow a slower braking schedule to avoid damaging the cargo

Question 2

How does brake fade affect a heavy vehicle descending a long steep hill?

Accepted Answer

Repeated hard braking overheats the brake drums or discs, reducing friction and extending stopping distances. Brake fade occurs when continuous braking generates heat that reduces friction between the brake lining and drum or disc. On a long descent this can make the vehicle nearly impossible to stop. The correct technique is to select a low gear before the descent and use engine braking to control speed, applying brakes only briefly if needed.

Answer

Brake fade only affects motorcycles; heavy vehicles use air brakes that are immune

Answer

Brake fade increases braking power by expanding the brake shoes against the drum

Answer

Brake fade causes the air pressure gauge to drop below the safe operating level immediately

Question 3

What is the primary purpose of an exhaust brake (Jake brake) on a heavy vehicle?

Accepted Answer

To use engine compression to slow the vehicle on descents without using the service brakes. An exhaust brake restricts the exhaust flow, turning the engine into an air compressor that creates retarding force. This slows the vehicle on descents and reduces heat build-up in the service brakes, helping prevent brake fade. It is one of the most effective tools for controlling speed on long downhill grades.

Answer

To reduce exhaust emissions by burning unburnt fuel in the exhaust system

Answer

To automatically apply the parking brake when the engine is switched off

Answer

To prevent the engine from over-revving when the accelerator is pressed too hard

Question 4

Before descending a long steep grade, what gear selection technique should a heavy vehicle driver use?

Accepted Answer

Select a low gear before starting the descent and maintain it throughout. The correct technique is to engage a low gear before the descent begins, not after gaining speed. This allows engine braking to control the vehicle's speed from the start, preventing the brakes from overheating. Attempting to downshift on a moving, heavily loaded truck travelling downhill is dangerous and may not be possible.

Answer

Begin in a high gear and downshift gradually once the vehicle gains speed

Answer

Place the gearbox in neutral to save fuel and allow free-rolling

Answer

Use the highest gear possible to keep engine revs low

Question 5

What happens to braking performance if air pressure in a pneumatic brake system drops below the minimum safe level?

Accepted Answer

Spring-loaded park brakes automatically apply, immobilising the vehicle. Air brake systems include a spring-brake (fail-safe) mechanism. If air pressure falls below a safe threshold, typically around 60 psi, the spring brakes automatically apply and hold the vehicle stationary. This is a safety feature, not a fault. A driver who hears a low-pressure warning buzzer must stop safely and investigate immediately.

Answer

The service brakes switch to a hydraulic backup circuit

Answer

The brakes lock permanently until the air tank is refilled at a service station

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The ABS system takes over to compensate for the reduced air pressure

Question 6

What is the correct way to test air brakes at the start of a shift?

Accepted Answer

Build air pressure to operating level, then apply the foot brake and check that pressure drops slowly within acceptable limits. The standard air-brake pre-trip test involves building system pressure to the normal operating range, holding the brake pedal depressed and monitoring the pressure gauge. The pressure should drop only slightly over one minute. Excessive drop indicates a leak that must be repaired before driving.

Answer

Drive at 30 km/h and perform a full emergency stop to confirm brake response

Answer

Apply and release the brakes five times rapidly to warm the brake linings

Answer

Open the drain valves to release any moisture and then drive normally

Question 7

When securing a load on a flatbed truck, what is the minimum requirement regarding tie-down points?

Accepted Answer

The combined rating of all tie-down straps or chains must equal at least the total weight of the cargo being secured. Qatar and GCC load-securing rules require that the aggregate working load limit of all tie-down devices meets or exceeds the weight of the cargo. Undersecured loads can shift, fall onto other vehicles, or cause the truck to roll over in a turn. Always verify exact requirements with the General Directorate of Traffic.

Answer

One tie-down strap at each end of the load is always sufficient regardless of weight

Answer

Only fragile goods require tie-downs; dense cargo is held by gravity alone

Answer

Tie-downs are only required when travelling on highways above 100 km/h

Question 8

Where should the heaviest items be placed when loading a rigid truck to optimise stability?

Accepted Answer

As low as possible and centred over the drive axles. Placing the heaviest items low and centred over the drive axles lowers the centre of gravity, improves traction on the drive wheels, and distributes weight correctly across all axles. A high or rear-heavy load raises the centre of gravity, increases rollover risk in corners and on crosswinds, and can overload rear axles.

Answer

At the very rear of the load bed to improve steering response

Answer

As high as possible to keep them away from road spray

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On the right side of the load bed to counteract the driver's weight

Question 9

A truck's front steering axle has a maximum allowed axle weight of 6 tonnes. The axle is currently carrying 7.5 tonnes. What is the most likely consequence?

Accepted Answer

Overloaded steering axle causes tyre overload, reduced steering control, and potential tyre failure. An overloaded steering axle causes the front tyres to carry more than their rated load, leading to overheating, increased wear, possible blowout, and reduced steering response. It also makes the vehicle illegal to operate. Fines, vehicle detention, and mandatory off-loading may result.

Answer

The front axle overload will automatically transfer weight rearward through the suspension

Answer

The vehicle's ABS system compensates and maintains normal steering feel

Answer

Overloading only affects fuel consumption and has no safety consequence

Question 10

Before loading a truck, where do you find the most weight it may legally carry?

Accepted Answer

On the vehicle's registration documents and the manufacturer's plate, and you must not exceed it. Each vehicle has its own permitted gross weight and axle loads, set by its design and registration. Load within them: overloading lengthens braking, overheats tyres and damages roads, and improper loads are on the fines schedule at QR 1,000 to 3,000 and 1 black point.

Answer

It is the same for every truck, 30 tonnes

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There is no limit as long as the tyres are not flat

Answer

Only the driving school can tell you

Doha General Directorate of Traffic - Qatar Heavy Vehicle Skills Test 1

The other 12 questions in this test

What this test covers

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