Theory test / Safety and your vehicle
Safety and your vehicle theory test questions
Up to date with the current Highway CodeLast reviewed October 2026
Safety and your vehicle is about the car itself: keeping it roadworthy, spotting faults early, understanding warning lights, and using equipment such as lights, the horn, seat belts and head restraints correctly. It also covers the environmental side of driving, like idling, fuel use and exhaust emissions, plus how to keep the car secure when you leave it.
Tyres come up a lot. The legal minimum tread depth for a car is 1.6 mm across the central three-quarters of the tread and around the whole circumference. Pressures should match the manufacturer's figure for the load you are carrying and are best checked weekly when the tyres are cold, because warm tyres give a misleadingly high reading. Under-inflated or over-inflated tyres affect both braking and steering.
Many questions describe a symptom and ask what it means. A car that pulls to one side when you brake most likely has a brake fault or incorrectly inflated tyres. A car that keeps bouncing after you push down on a corner has worn shock absorbers. A warning light that stays on after the engine starts, or comes on while you are driving, means you should stop safely and find out why. The charge warning light usually means the battery is not being charged.
Learners often slip on the timed and conditional rules. You must not sound your horn while stationary, or in a built-up area between 11.30 pm and 7 am, unless another road user poses a danger (Rule 112). Hazard warning lights may only be used while moving on a motorway or unrestricted dual carriageway to warn of a hazard ahead (Rule 116). A rear-facing baby seat must never go in a seat protected by an active frontal airbag (Rule 101), and the driver is responsible for passengers under 14 wearing a belt or the correct child restraint (Rule 100).
On the environmental side, switch the engine off if you expect to be stationary for more than a couple of minutes, unless you are held in traffic (Rule 123). Coasting in neutral removes engine braking and reduces your control (Rule 122). Smooth, planned driving, correct tyre pressures and removing an empty roof box all cut fuel use. When you leave the car, lock it, close the windows, and take valuables and documents with you.
Try 5 free questions
No account needed. Pick an answer to see whether it is right and why.
What is the minimum legal tread depth for the tyres on a car?
The free questions with answers
1. What is the minimum legal tread depth for the tyres on a car?
Answer: 1.6 mm across the central three-quarters of the tread
Cars, light vans and light trailers must have at least 1.6 mm of tread across the central three-quarters of the tread and around the entire circumference. Driving on tyres below this is illegal and can bring penalty points.
2. A red warning light comes on in your instrument panel while you are driving. What should you do?
Answer: Stop safely and find out what the light means
Warning lights that come on while you are driving can mean a dangerous fault is developing. Stop when it is safe and investigate, using the vehicle handbook if you are not sure what the light means.
3. When may you use hazard warning lights while your car is moving?
Answer: When warning drivers behind of a hazard on a motorway
Rule 116 only allows hazard lights while moving on a motorway or unrestricted dual carriageway, to warn traffic behind of a hazard or obstruction ahead. Use them just long enough for the warning to be seen. They are not allowed while being towed.
Highway Code rule 116
4. Your car pulls to one side every time you brake. What is the most likely cause?
Answer: A brake fault or incorrectly inflated tyres
Pulling under braking usually points to a brake fault or tyres at the wrong pressure. Get it checked by a garage straight away, as it can make the car hard to control in an emergency stop.
5. Unless another road user poses a danger, you must not use your horn in a built-up area between which times?
Answer: 11.30 pm and 7 am
Rule 112 bans the horn in built-up areas between 11.30 pm and 7 am, and at any time while you are stationary, except when another road user poses a danger. The horn is only for warning others that you are there.
Highway Code rule 112
Questions people ask
- What is the minimum legal tread depth for car tyres?
- 1.6 mm across the central three-quarters of the tread width, all the way round the tyre. Grip in the wet drops noticeably well before you reach that limit, so many drivers replace tyres earlier.
- When can I use my hazard warning lights while driving?
- Only on a motorway or unrestricted dual carriageway, briefly, to warn the traffic behind you of a hazard or obstruction ahead. Otherwise they are for when you are stationary and temporarily obstructing traffic (Rule 116).
- What should I do if a dashboard warning light comes on?
- Stop when it is safe and find out what the light means, using the handbook if needed. Warning lights can point to a serious fault developing, so do not just carry on and hope it goes out.
- Why does the theory test ask about fuel economy and emissions?
- The Highway Code expects drivers to cut unnecessary pollution and noise, for example by not leaving an engine idling (Rule 123). Smooth driving that saves fuel is also usually safer, because it relies on planning ahead.
Other theory test topics
Rule references: The Highway Code (GOV.UK), Open Government Licence v3.0. Questions and explanations are written by PassRank and are not the official DVSA revision questions.