Vehicle Knowledge and Mechanical Safety
This domain tests your ability to spot a vehicle defect before it becomes a crash risk. Questions cover tyres, brakes, lights, fluids, warning symbols and safety systems, and ask what a driver should check or do.
Tyres and pressure
Legal tread depth is commonly 1.6 mm across the central three-quarters of the tyre. Check pressure when tyres are cold, using the vehicle placard. Look for bulges, cuts and uneven wear. Never reduce pressure after driving, because tyres heat up and pressure rises.
Brakes, fluids and lights
A soft or spongy brake pedal can mean air or a leak; investigate immediately. Brake fluid absorbs moisture over time and needs periodic replacement. Check coolant, engine oil and washer fluid regularly. Red warning lights mean stop; amber means caution and inspect; green means a system is on.
Safety systems
ABS prevents wheel lock during hard braking, ESP helps control skids, and seatbelts plus correct child restraints are the primary crash protection. Traction control cannot overcome poor tyres or excessive speed.
Worked example
A tyre-pressure warning light appears on a cold morning. Check pressures cold and inflate to the placard, not to the maximum printed on the sidewall. Do not release pressure from a warm tyre after driving. Reasoning: cold pressure is the reference; setting hot pressure leaves tyres underinflated when cold.
Traps that cost marks
Overinflating to save fuel; mixing tyre types or sizes; ignoring brake-fluid service intervals; treating fog lights as headlights.
Key points
- Minimum tread depth is commonly 1.6 mm across the central three-quarters.
- Check tyre pressure cold and follow the vehicle placard.
- A soft brake pedal means air or a leak; investigate immediately.
- Red warning lights mean stop; amber means inspect.
- ABS and ESP cannot compensate for poor tyres or excessive speed.