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    When travelling in fog you should reduce your speed. Why is this?

    DVSA-style practice question · Vehicle Handling

    The answer options

    • You will be dazzled by lights
    • The engine needs longer to warm up
    • The brakes will not be as efficient
    • It is harder to see what is ahead on the roadCorrect

    Why the other options are wrong

    • “You will be dazzled by lights” is a distractor. It does not meet the standard the question is testing, which it is harder to see what is ahead on the road 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.
    • “The engine needs longer to warm up” is a distractor. It does not meet the standard the question is testing, which it is harder to see what is ahead on the road 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.
    • “The brakes will not be as efficient” is a distractor. It does not meet the standard the question is testing, which it is harder to see what is ahead on the road 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

    Fog severely reduces visibility, making it much harder to see hazards, road markings, and other vehicles ahead. You must slow down so you can stop safely within the distance you can see clearly, as advised by the Highway Code. Although damp surfaces may affect grip, the primary danger is poor vision. Avoid using main-beam headlights, as the light reflects off the fog and will dazzle you.

    What vehicle handling covers

    • · Front and rear fog lights and the 100-metre visibility rule
    • · Descending steep hills in a lower gear and engine braking
    • · Traffic calming, humps, and driving over tram rails
    • · Night driving, dipped headlights and dazzle from oncoming traffic

    Mistakes learners repeat on this topic

    • · Leaving rear fog lights on after visibility improves
    • · Coasting downhill in neutral to save fuel
    • · Using full beam on a lit motorway or behind another vehicle
    • · Accelerating between speed humps instead of holding a steady speed

    Instructor tip: Any question with fog in it usually turns on the 100-metre rule — check visibility before you check the lights.

    How this comes up in the real test

    Questions from vehicle handling 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 Vehicle HandlingSit a full mock test

    More vehicle handling questions

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