Ireland Truck Theory Test key terms

A bus lane where buses travel in the opposite direction to the general traffic flow on a one-way street. Other vehicles may not use it, and drivers must watch for buses approaching head-on.

A road marking of short white dashes that may be crossed when it is safe to do so, for example when changing lane or overtaking. It is advisory rather than prohibitive in most situations.

An unbroken white centre line that must not be crossed except in specific permitted circumstances, such as entering a premises or where a broken line accompanies it on the driver's side.

A road marking along the edge of the carriageway indicating parking restrictions during posted times, commonly at peak periods. The accompanying sign or plate states when the restriction operates.

A marking along the edge of the carriageway meaning parking is prohibited at all times, unless signs state otherwise. Stopping briefly to set down or pick up may still be allowed where a sign permits.

A stretch of road where stopping and parking are prohibited during the times shown on the accompanying sign, usually to keep traffic flowing. Drivers may not wait there even briefly except in an emergency.

The marked lane on the left of a motorway for emergency use only. It is not a driving lane, and stopping there is permitted only for breakdown, illness or another genuine emergency.

A junction marked with yellow criss-cross lines where a driver must not enter unless the exit is clear. The exception allows entry when turning right and only oncoming traffic prevents the turn.

An octagonal red sign requiring a complete stop at the line before proceeding when safe. It differs from a yield sign, where a driver need only give way if traffic is approaching.

An inverted triangular sign instructing a driver to give way to traffic on the road being joined. The driver must slow, look and proceed only when it is safe, stopping if necessary.

A circular junction where traffic already on the roundabout generally has priority. Drivers approach with care, yield as signed, and signal their intended exit to other road users.

A circular white sign with a black diagonal band showing that the default national limit applies to that road. The actual limit depends on the road type and vehicle category.

A road in a built-up area where a special speed limit applies, shown by circular speed limit signs. The limit is stated in kilometres per hour and applies to all vehicles unless a lower limit is posted.

The class a vehicle falls into according to its design, weight and use, such as car, rigid truck or articulated truck. The category determines applicable speed limits, licence requirements and driving rules.

The maximum weight a vehicle is designed to carry, including its own weight and any load, as specified by the manufacturer. It is used to determine licensing, speed limits and operator obligations.

The difference between a vehicle's design gross vehicle weight and its unladen weight, representing the maximum load it may legally carry. Overloading reduces braking performance and may invalidate insurance.

The practice of restraining cargo so it cannot shift, fall or be shed during a journey. It involves correct use of straps, curtains, twist locks and load distribution within the vehicle's weight limits.

A pre-journey inspection of a vehicle's tyres, lights, brakes, fluids, load and bodywork carried out by the driver. It aims to identify defects before they cause a breakdown or collision.

The documented process of recording a vehicle fault and passing it to the operator for repair. Drivers must not use a vehicle with a known serious defect that affects road safety.

The minimum legal depth of tread on a vehicle tyre, measured in millimetres across the central portion of the tyre. Insufficient tread reduces grip in wet conditions and is an offence.

The amount of air inside a tyre, which should be checked when tyres are cold and set to the manufacturer's recommendation. Incorrect pressure affects handling, braking and fuel consumption.

The condition of a vehicle being fit and safe to use on public roads, meeting legal standards for brakes, tyres, lights, steering and bodywork. It is checked at annual tests and daily by drivers.

The periodic statutory inspection that commercial vehicles must pass to remain legally on the road. It covers safety systems and emissions and is more frequent than the test for private cars.

The loss of braking power caused by overheating of brake components, often after prolonged use on long descents. Drivers should use engine braking and lower gears to reduce the risk.

Slowing a vehicle by releasing the accelerator and using the resistance of the engine in a lower gear. It reduces reliance on the footbrake on long or steep descents.

The skill of spotting developing risks on the road early enough to respond smoothly and safely. It relies on scanning ahead, checking mirrors and anticipating the actions of others.

The gap a driver keeps to the vehicle ahead, commonly measured by the two-second rule in dry conditions. The gap should increase in rain, darkness or when carrying a heavy load.

The total distance travelled from the moment a hazard is seen until the vehicle comes to rest. It combines thinking distance and braking distance and grows sharply with speed.

The continuous use of mirrors, blind-spot checks and forward scanning to stay aware of surrounding traffic. Good observation underpins safe manoeuvring, lane changes and junction decisions.

An area around a vehicle that cannot be seen directly or through the mirrors. Large vehicles have extensive blind spots, so drivers must check them physically before moving off or turning.

A road user at greater risk of injury in a collision, such as a pedestrian, cyclist or motorcyclist. Drivers must give them extra space and anticipate unpredictable movement.

The mental and physical tiredness that impairs reaction time, attention and judgement. Drivers should stop for rest breaks and must not continue when drowsiness affects their driving.

The delay between a driver perceiving a hazard and taking action such as braking. It lengthens with fatigue, alcohol, drugs and distraction, increasing the stopping distance.

The legal limits on driving time and the required rest periods for professional drivers. They are designed to protect road safety and the health of drivers and are enforced through tachograph records.

The minimum uninterrupted rest a professional driver must take within each 24-hour period. It can be a regular or reduced rest, and its length depends on the applicable rules.

The mandatory pause a driver must take after a specified period of driving or work before continuing. It must be taken as rest and cannot be replaced by other duties.

A recording device fitted to commercial vehicles that logs driving time, rest, speed and distance. Records may be analogue or digital and must be produced on request by enforcement officers.

The certificate of professional competence that professional drivers must hold and keep current through periodic training. It demonstrates a minimum standard of knowledge and safety awareness.

The authorisation a transport operator needs to run commercial vehicles, granted subject to conditions on maintenance, finance and repute. It places duties on the operator for vehicle and driver compliance.