Jordan Driving Theory Heavy key terms

The maximum total weight a vehicle is designed and legally permitted to carry, including the chassis, body, fuel, driver, passengers and cargo, as set by the manufacturer.

The weight of cargo, passengers and any added equipment a vehicle may carry, calculated as the difference between its GVWR and its kerb (tare) weight.

The unladen weight of a vehicle as it stands, including fuel, coolant, oils and standard tools, but excluding cargo, passengers and the driver's personal effects.

The portion of a vehicle's total weight carried by a single axle, which must stay within the manufacturer's and legal per-axle limits to avoid overloading and brake imbalance.

Spreading cargo weight correctly along the vehicle so each axle carries its permitted share, keeping steering and drive axles properly loaded, and avoiding excessive rear-axle stress.

The methods, such as straps, chains, ratchets and lashings, used to stop cargo shifting, sliding or falling from a vehicle during normal driving, cornering and braking.

The maximum load a strap, chain or lashing may safely hold in normal use, marked on the component and used to confirm the securing arrangement is strong enough for the load.

The point where a vehicle's or load's weight is concentrated. A high centre of gravity increases the risk of rollover, especially in heavy vehicles during cornering or rapid steering.

The likelihood that a vehicle will tip onto its side, increased by high loads, soft road edges, hard cornering, sudden steering and excessive speed on curves and ramps.

A braking system powered by compressed air stored in reservoirs, using air pressure to apply brakes through valves and chambers, with spring brakes for parking and emergency stopping.

A buzzer and light that alerts the driver when reservoir pressure drops below the safe operating level, signalling that brakes may fail or the vehicle may not stop reliably.

A condition where compressed-air reservoir pressure falls below the safe minimum, reducing braking force and eventually triggering spring-brake application, so the vehicle must be stopped and checked.

A parking and emergency brake held applied by a heavy spring and released by air pressure; if air pressure is lost, it automatically engages to stop the vehicle.

Loss of braking power caused by overheating of brake drums, discs or linings, commonly after prolonged downhill braking, and avoided by using a low gear and engine braking.

Using a low gear and the engine's compression resistance to slow the vehicle, reducing reliance on wheel brakes on long descents and helping prevent overheating and brake fade.

A pre-trip test confirming the parking/spring brake holds the vehicle on a slope or resists forward creep, verifying that the brake system is functioning before departure.

The systematic check of tyres, brakes, lights, fluids, load and safety equipment carried out before starting a journey, to confirm the vehicle is roadworthy and legal to drive.

The measured thickness of the tyre's tread pattern; heavy vehicles must meet legal minimum depths, and insufficient tread reduces grip, especially in rain and on loose surfaces.

Choosing the correct gear for speed, gradient and load so the engine operates efficiently and the vehicle remains controllable, using low gears for steep descents and heavy loads.

The safe speed for a bend, set by road design, load height and surface grip; heavy vehicles must slow before the curve because centrifugal force grows quickly with speed.

The gap kept behind the vehicle ahead, increased for heavy vehicles and poor conditions so there is enough time and space to stop safely if traffic suddenly slows.

The total distance travelled from seeing a hazard to coming to rest, made up of thinking distance plus braking distance, and much longer for heavy, loaded vehicles.

The delay between noticing a hazard and beginning to brake or steer, typically around one second but lengthened by fatigue, distraction, alcohol or poor visibility.

An area around a heavy vehicle that the driver cannot see in mirrors, especially close alongside and directly behind, where other road users may be hidden.

Regular use of the vehicle's mirrors to monitor blind spots, traffic and load before changing lanes, turning or braking, reducing the risk of collision with overtaking vehicles.

Physical and mental tiredness that slows reaction, impairs judgement and increases crash risk; managed through adequate rest, breaks and respecting driving-hour limits.

The legal maximum time a driver may spend driving within a working day or week, recorded to prevent excessive continuous driving and reduce fatigue-related crashes.

The minimum uninterrupted break a driver must take between periods of driving or work, allowing recovery from fatigue and required by law for heavy-vehicle drivers.

An approved recording device that logs driving time, rest, speed and distance, providing evidence that the driver is complying with driving-hour and rest-period rules.

A traffic sign stating the maximum permitted weight or axle load for a road, bridge or structure, which the driver must check against the vehicle's actual weight before proceeding.

A warning sign showing the maximum vehicle height permitted ahead, such as at a bridge or tunnel, so drivers of tall vehicles can divert before striking the structure.

A sign, usually circular, that gives an instruction drivers must obey, such as a speed limit, weight limit, no-entry or compulsory direction, and breaches are offences.

Painted lines, arrows and symbols on the road surface that guide, warn or restrict traffic, such as lane lines, stop lines, hatched areas and edge lines.

The skill of scanning ahead and anticipating developing risks, such as pedestrians, junctions, parked vehicles or changing traffic, early enough to respond smoothly and safely.

Techniques for regaining grip when wheels lose traction, including easing off the accelerator, steering smoothly and avoiding harsh braking, especially on wet or loose surfaces.

A portable device carried on the vehicle for tackling small fires; the driver should know its location, type and use, and evacuate if the fire is large or spreading.

The sequence followed after a crash or breakdown: securing the scene, warning traffic, calling emergency services, assisting casualties and exchanging details safely.

Immediate basic care given to an injured person before professional help arrives, such as controlling bleeding, maintaining breathing and keeping the casualty warm and still.

Fuel-efficient driving habits such as smooth acceleration, early gear changes, steady speed, correct tyre pressure and avoiding unnecessary idling, which cut fuel use and emissions.

Leaving the engine running while the vehicle is stationary, which wastes fuel, increases emissions and noise, and is restricted or discouraged in many areas.

A document proving the vehicle is covered by valid insurance, showing the policy details and period of cover, which the driver must be able to produce when required.

The official permit authorising a person to drive a specified category of vehicle; heavy vehicles require the correct class, and driving without it is an offence.

The official record and document linking a vehicle to its registered keeper, plate number and technical details, required for legal road use and checked during roadside inspections.