Vehicle safety
This domain tests pre-trip checks and understanding the vehicle systems that affect safety: tyres, brakes, lights, steering, mirrors, restraints and load security. Many exam questions link a defect to the risk it creates.
Core rules
- Tyres: minimum tread depth is 1.5 mm. Check pressure when cold and look for cuts, bulges or uneven wear. Worn or mismatched tyres reduce grip, especially in wet conditions.
- Brakes: check pedal feel, warning lights and any pulling. Do not ignore brake warnings.
- Lights: headlights, brake lights, indicators and hazard lights must be clean and working.
- Mirrors and windscreen: adjust mirrors, keep glass clean, and check wipers and washers.
- Seatbelts and child restraints: check condition and correct fit. Loose objects can become dangerous in a crash.
- Loads: secure them, do not overload, and remember roof loads affect stability.
- Warning lights: stop and investigate serious warnings rather than continuing.
Worked example
A tyre measures 1.2 mm tread. It may look usable, but it is below the 1.5 mm minimum, so it fails a WoF inspection and has poor wet grip. Replace it before driving. The reasoning is measurable: 1.2 mm is less than the legal minimum, so the defect is not a matter of opinion.
Traps
Checking tread only at the centre; overinflating tyres; ignoring a brake warning light; leaving a load unsecured; fitting a child restraint incorrectly; and assuming a routine service replaces a WoF check.