Saudi Heavy Vehicle Theory flashcards
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35 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Heavy vehicle licence category
- A licence class required to drive trucks or combinations above the light vehicle weight threshold; driving a heavier class than endorsed is treated as driving without the correct licence.
- Permissible gross vehicle weight
- The maximum laden weight the manufacturer declares for the vehicle, including chassis, body, fuel, driver and cargo; exceeding it is an offence and raises brake and tyre failure risk.
- Axle load limit
- The maximum weight permitted on a single axle or axle group; overloading one axle is an offence even when total vehicle weight is legal, and it increases tyre and brake stress.
- Valid registration and insurance
- Heavy vehicle drivers must carry a valid licence for the class, the vehicle registration (istimara) and proof of valid insurance; driving without insurance is a separate offence.
- Solid versus broken centre line
- A solid centre line may not be crossed; a broken centre line may be crossed only when safe and the overtaking manoeuvre can be completed before the line becomes solid again.
- Warning sign shape
- Warning signs are triangular with a red border and yellow or white background, announcing hazards ahead such as bends, steep descents, junctions, livestock crossing or loose gravel.
- Heavy vehicle lane rule
- Heavy vehicles are generally restricted to the right-hand lane on multi-lane highways and may use the left lane only to overtake or to follow a mandatory direction sign.
- Roundabout priority
- Traffic already circulating in a roundabout has priority unless signs or signals indicate otherwise; heavy vehicles must signal exit and check the right blind spot before leaving.
- Periodic technical inspection
- The fahs inspection required at intervals set by the licensing authority; without a valid certificate the vehicle cannot be legally registered or operated on public roads.
- Pre-trip tyre check
- Check tread depth, cuts, bulges, inflation and dual tyre spacing; tyres on the same axle must match in size and construction, and exposed cord means unroadworthy.
- Air leak test
- With the engine off and tanks full, pressure should not drop more than the manufacturer's limit in one minute with brakes released; a steady or rapid loss indicates a leak.
- Low-pressure warning test
- The low-pressure buzzer and light must activate before pressure falls below the safe operating threshold; if they fail to work, the vehicle must not be driven.
- Governed air pressure
- Heavy vehicle air systems typically run at 8–8.5 bar (about 115–125 psi); the compressor refills the tanks and cuts out at the governor setting, cutting back in lower.
- Trailer breakaway protection
- The supply (emergency) line feeds the trailer; loss of supply pressure triggers the trailer relay valve to apply the trailer brakes automatically, stopping a detached trailer.
- Spring brakes
- Parking brakes applied by mechanical spring force when air pressure is released; they serve as the parking brake and apply automatically on catastrophic pressure loss.
- Brake fade
- Loss of braking caused by overheated drums and linings on long descents; control speed by selecting a low gear before the descent and braking intermittently, not continuously.
- Stopping distance formula
- Stopping distance equals perception distance plus reaction distance plus braking distance; at 90 km/h a 1.5-second reaction alone covers about 37 metres.
- Three-second following gap
- A minimum gap of at least three seconds in good conditions, increased to four seconds or more when laden, at night, in rain, or when dust and spray reduce visibility.
- Descent gear selection
- Descend long gradients in the same gear needed to climb them; if the vehicle accelerates in that gear, select a lower gear before speed builds.
- Speed within visible distance
- Adjust speed so the vehicle can stop within the distance seen to be clear; on crests, in fog or blowing dust, visible distance rather than the posted limit sets safe speed.
- Overtaking requirements
- Overtaking requires clear sight distance, a legal broken line or permitted zone, and enough road to return to the right lane; heavy vehicles need far more distance than cars.
- Load centre of gravity
- Keep the centre of gravity low and centred between the axles; a high or rearward load reduces steering-axle grip and increases rollover risk, especially in fast lane changes.
- Load restraint strength
- Secure cargo with rated straps, chains, binders or twist locks; aggregate lashing strength must suit the load, and the load must be restrained against forward, rearward and lateral movement.
- Rechecking lashings
- Check lashings after the first few kilometres and at each stop; straps stretch, knots loosen and loads settle, so a load secure at departure may loosen later.
- Covering loose loads
- Loose loads such as sand, gravel or aggregate must be covered with a tarpaulin so material cannot spill onto the road or strike following traffic.
- Tyre blow-out response
- Hold the steering firmly with both hands, avoid hard braking, ease off the accelerator and let the vehicle slow before steering to the shoulder.
- Brake failure response
- Pump the pedal if air pressure is suspect, downshift progressively, use the engine brake and retarder, then apply the emergency or spring brake and look for a safe runoff.
- Jack-knife response
- If a trailer starts to jack-knife, release the brakes briefly to let it straighten, then reapply gently; hard braking at that moment worsens the fold.
- Fatigue remedy
- The only effective remedy for fatigue is sleep; fresh air, loud music and caffeine give only brief relief and do not restore alertness.
- Fatigue warning signs
- Heavy eyelids, yawning, drifting within the lane, missing signs or exits, and difficulty remembering the last few kilometres indicate the driver must stop and rest.
- Medicine and driving
- Prescription and over-the-counter medicines can cause drowsiness; drivers must check the label and ask a pharmacist or doctor before driving a heavy vehicle.
- Incident scene protection
- At an incident, stop, switch off the engine, switch on hazard lights and set out warning triangles behind the vehicle, further back on fast roads, before assisting anyone.
- Saudi emergency number
- The unified emergency number in Saudi Arabia is 911; traffic accidents must be reported to the traffic police (Muroor) for insurance and liability purposes.
- Suspected spinal injury
- Do not move an injured person unless there is immediate danger such as fire or traffic; suspected spinal injury makes unnecessary movement dangerous.
- Severe bleeding control
- Control severe bleeding with direct pressure and a clean dressing; keep the casualty warm and monitor breathing until emergency help arrives.