--- title: "Before slowing or stopping your vehicle, what… | Theory Test" description: "Before slowing or stopping your vehicle, what is something you must do? The correct answer is “Use your mirrors”. 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Always check your mirrors before changing your speed or direction, following the standard MSM routine advised in The Highway Code. Checking your mirrors before slowing down or stopping allows you to see what is happening behind you, such as a vehicle following too closely. You can then adjust your braking safely to avoid a rear-end collision. Flashing your lights or sounding your horn is unnecessary and could easily mislead other road users." }, "suggestedAnswer": [ { "@type": "Answer", "text": "Select a higher gear" }, { "@type": "Answer", "text": "Flash your headlights" }, { "@type": "Answer", "text": "Sound your horn" } ] } } ] --- Get an exclusive 15% off - Offer ends next week! 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DVSA-style practice question · Alertness ## The answer options - Select a higher gear - Flash your headlights - Sound your horn - Use your mirrors**Correct** ## Why that is the answer Always check your mirrors before changing your speed or direction, following the standard MSM routine advised in The Highway Code. Checking your mirrors before slowing down or stopping allows you to see what is happening behind you, such as a vehicle following too closely. You can then adjust your braking safely to avoid a rear-end collision. Flashing your lights or sounding your horn is unnecessary and could easily mislead other road users. ## How this comes up in the real test Questions from alertness 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 Alertness](/theory/quiz/alertness)[Sit a full mock test](/theory/mock-test) ## More alertness questions - [Before making a U-turn, what should you do?](/theory/questions/before-making-a-u-turn-what-should-you-do) - [How can you make sure that a satellite navigation (satnav) system doesn’t distract you when you’re driving?](/theory/questions/how-can-you-make-sure-that-a-satellite-navigation-satnav-system-doesn-t-distract-you-when) - [How should you pass the cyclists?](/theory/questions/how-should-you-pass-the-cyclists) - [Something is hanging from your rearview mirror. Why might this pose a risk?](/theory/questions/something-is-hanging-from-your-rearview-mirror-why-might-this-pose-a-risk) - [The windscreen pillar is restricting your view when waiting to emerge from a junction. What should you be especially cautious of?](/theory/questions/the-windscreen-pillar-is-restricting-your-view-when-waiting-to-emerge-from-a-junction-what) - [There is a hazard ahead. Why should you use your mirrors?](/theory/questions/there-is-a-hazard-ahead-why-should-you-use-your-mirrors) ## Ready to book the real thing? Full Membership is £49 and covers your DVSA booking, one resit with no minimum mark, cancellation checking on theory and practical tests, and the Learning Hub. [Book my theory test](/theory/signup) ## Passed your theory? Get the practical booked Your theory certificate lasts two years. 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