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    A vehicle MOT test will include an exhaust emissions test. What is the reason for this?

    DVSA-style practice question · Safety and your Vehicle

    The answer options

    • To see which fuel supplier is the most popular
    • To cover the cost of garage equipment
    • To ensure diesel and petrol engines give off the same fumes
    • To help protect the environmentCorrect

    Why the other options are wrong

    • “To see which fuel supplier is the most popular” is a distractor. It does not meet the standard the question is testing, which to help protect the environment does. Picking it in the real test costs a mark you cannot get back, and with a pass mark of 43 out of 50 you only have seven to spare.
    • “To cover the cost of garage equipment” is a distractor. It does not meet the standard the question is testing, which to help protect the environment does. Picking it in the real test costs a mark you cannot get back, and with a pass mark of 43 out of 50 you only have seven to spare.
    • “To ensure diesel and petrol engines give off the same fumes” is a distractor. It does not meet the standard the question is testing, which to help protect the environment does. Picking it in the real test costs a mark you cannot get back, and with a pass mark of 43 out of 50 you only have seven to spare.

    Why that is the answer

    The exhaust emissions test measures the harmful gases released by your vehicle. Ensuring these pollutants stay within legal limits helps protect the environment and improves air quality. Petrol and diesel engines produce different emissions, so the test checks each against specific standards rather than making them equal. DVSA guidelines require this check during the MOT test to reduce environmental damage and ensure your vehicle remains roadworthy.

    What safety and your vehicle covers

    • · Legal minimum tread depth of 1.6mm across the central three-quarters
    • · Dashboard warning lamp colours and which mean stop immediately
    • · Braking, steering and suspension faults and how they feel
    • · Fuel economy, emissions and eco-safe driving technique

    Mistakes learners repeat on this topic

    • · Quoting 1.6mm as an all-weather safe depth rather than the legal minimum
    • · Checking tyre pressures when the tyres are hot instead of cold
    • · Treating an amber warning lamp as something to ignore
    • · Forgetting that an over-inflated tyre wears in the centre, not the edges

    Instructor tip: Learn the warning lamp colours as a traffic-light system: red stop, amber investigate, green or blue informational.

    How this comes up in the real test

    Questions from safety and your vehicle appear throughout the 50-question multiple-choice section, and the wording changes between versions. Learn the rule rather than the sentence: the DVSA can ask the same point from the opposite direction, and a memorised answer falls over the moment the phrasing moves.

    The pass mark is 43 out of 50, so seven wrong answers is your entire margin. If a whole category is shaky, run the topic practice below until you are getting every question right for the right reason, then go back to full mocks under the clock.

    Practise Safety and your VehicleSit a full mock test

    More safety and your vehicle questions

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