Oman Heavy Vehicle Theory key terms

The legal entitlement of a road user to proceed first in a given situation, often indicated by signs, signals, or road markings. Failing to yield when required is a common cause of collisions.

A circular junction where traffic flows in one direction around a central island. In Oman, vehicles already on the roundabout generally have priority, and entering drivers must yield.

A red octagonal sign requiring a complete stop at the stop line or before entering the intersection. You must yield to all traffic and pedestrians before proceeding.

An inverted triangular sign indicating that you must slow down and give way to traffic on the intersecting road. Stop if necessary to avoid a collision.

A circular sign with a red border displaying the maximum permitted speed in kilometres per hour. Exceeding it is an offence and increases stopping distance and crash severity.

The practice of staying within your lane, signalling before changing lanes, and not straddling lanes. Good lane discipline reduces conflicts and improves traffic flow.

A continuous line marking the edge of a lane or carriageway that must not be crossed except in an emergency. It often separates traffic from a hard shoulder or indicates no overtaking.

A dashed line separating lanes of traffic moving in the same direction. You may cross it to change lanes or overtake when it is safe and you have signalled.

A place where two or more roads meet or cross. Junctions require heightened awareness; you must observe signs, signals, and road markings and yield as required.

A systematic check of a vehicle before driving, covering tyres, lights, brakes, fluids, mirrors, and load security. It helps detect defects that could cause breakdowns or crashes.

The depth of the grooves on a tyre, which affects grip and water dispersion. Legal minimums apply; worn tyres increase stopping distances and the risk of aquaplaning.

A temporary loss of braking power caused by overheating, often after repeated or prolonged braking. It can be prevented by using engine braking and avoiding riding the brakes.

A braking system that uses compressed air to apply the brakes. It requires regular checks of air pressure, leaks, and moisture in the tanks to ensure reliable operation.

A check of braking performance, often done at low speed after starting the engine. It confirms that the brakes respond correctly and that there are no air or fluid leaks.

The arrangement of cargo so that weight is spread correctly across the vehicle's axles. Poor distribution can affect steering, braking, and stability, and may exceed axle limits.

The use of straps, chains, or other restraints to prevent cargo from shifting or falling. Unsecured loads are dangerous and illegal, and can cause serious accidents.

The maximum total weight of a vehicle including its chassis, body, fuel, driver, passengers, and cargo. Exceeding it is unsafe and illegal, and can damage the vehicle.

The maximum permitted weight on a single axle or axle group. Overloading an axle can cause tyre failure, brake problems, and road damage, and is subject to fines.

The maximum vehicle height allowed on a road or through a structure, often shown on signs. Drivers must know their vehicle's height, including any load, to avoid collisions.

The vertical or horizontal space available for a vehicle to pass safely under a bridge or through a gap. Insufficient clearance can cause serious damage or injury.

The length, width, height, and weight of a vehicle, including any load. Knowing these is essential for safe navigation, compliance with regulations, and avoiding bridge strikes.

A loss of tyre contact with the road surface due to a layer of water, leading to reduced steering and braking control. It is more likely at high speed or with worn tyres.

Slowing a vehicle by releasing the accelerator and using the engine's resistance, often by shifting to a lower gear. It helps control speed on long descents without overheating the brakes.

Driving on steep, winding roads where speed control, gear selection, and awareness of blind corners are critical. Use lower gears and avoid coasting to maintain control.

A state of physical or mental tiredness that impairs alertness, reaction time, and judgement. It is a major cause of crashes and must be managed with rest breaks.

The physical and mental condition required to drive safely, free from illness, fatigue, alcohol, drugs, and distraction. Drivers are responsible for ensuring they are fit to drive.

Any activity that diverts attention from driving, such as using a phone, eating, or adjusting controls. Even brief distractions can lead to serious accidents.

The ability to identify and anticipate dangerous situations on the road early enough to react safely. It involves scanning ahead, checking mirrors, and predicting other road users' actions.

The gap between your vehicle and the one ahead, which should allow enough time to stop safely if the leading vehicle brakes suddenly. A common guideline is at least two seconds in good conditions.

The total distance a vehicle travels from the moment the driver perceives a hazard until it comes to a complete stop. It includes reaction distance and braking distance, and increases with speed and load.

Adjusting your speed according to road conditions, traffic, visibility, and legal limits. Driving too fast for conditions is a leading cause of crashes, especially in rain or on curves.

The immediate assistance given to an injured person before professional help arrives. Basic skills include controlling bleeding, maintaining breathing, and not moving casualties unnecessarily.

The actions taken after a crash or breakdown to protect the scene, call for help, and assist casualties. It includes warning other traffic and providing accurate information to emergency services.

Making a crash or breakdown scene safe by warning approaching traffic, using hazard lights and triangles, and keeping people away from danger. This prevents secondary collisions.

A device that records driving time, speed, and rest periods. It is used to enforce driving hours regulations and ensure drivers do not exceed limits.

The maximum time a driver is allowed to drive before taking a break or rest. These limits are designed to reduce fatigue-related accidents and are legally enforced.

A period of time during which a driver stops driving to rest. Adequate rest breaks are essential to combat fatigue and are required by law for certain vehicles.