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  • Andy Lloyd

How Car Mirrors Keep You Safe on the Road

Here's a quick summary of some of the key advice from the Highway Code regarding mirror usage:

Let's start with the basics. When driving, as well as paying attention to the road ahead, you'll need to check three mirrors: one interior (middle mirror) and two exterior (left or right door mirror).

Your interior mirror is fixed onto the inside of your windscreen and allows you to see directly behind you. Most rear-view mirrors are flat, and distance and size are accurately reflected. This, in turn, allows you to more accurately judge the speed and position of other cars.

Exterior mirrors are found on either side of the car. These are convex mirrors, therefore curved which gives you a broader field of vision. The downside is that convex mirrors can make objects appear to be further away than they really are.

Both types of mirror have their own advantages—therefore it's good practice to use them in pairs, maximising both your vision and accuracy.

What does the Highway Code say about car mirrors?

Without mirrors you wouldn't be able to tell what was going on behind you without physically turning to crane your neck. As a result, they're mandatory equipment for any car on the road.

I am sure it won't surprise you to learn that there are dozens of references to mirrors in the Highway Code; After all, this is the go-to document for any road user in the UK— so, it's only logical that it provides drivers with advice on how and when to use their mirrors.

Here's a quick summary of some of the key advice from the Highway Code regarding mirror usage:

  • Before setting off ensure you adjust your mirrors for comfort, full control and maximum vision.

  • Use all mirrors to check the road is clear before moving off.

  • Use mirrors effectively throughout your journey so that you know what is behind and to each side of you.

  • Before you change direction or speed, use your mirrors in good time. This gives any drivers around you appropriate time to react and ensures drivers trying to overtake you won't be left in a vulnerable position.

  • Be aware that your mirrors won't cover all areas, and you may need to look round to check blind spots.

There are plenty of rules and guidelines relating to specific scenarios you'll encounter on the road. One more tip you'll find repeated plenty of times throughout the Highway Code is to remember Mirror - Signal - Manoeuvre. This is something all drivers should be aware of, but it never hurts to get a reminder!

  • Before manoeuvring, use your mirrors in good time to check the position and speed of traffic behind you.

  • Signal if you consider it to be necessary—and do so in good time. Always check your mirrors before signalling.

  • Finally, manoeuvre if it's safe to do so.

When will I need to use my mirrors on the road?

As the section above clarifies, mirror usage should be continuous during your drive—and you should regularly check your mirrors even when driving along a straight road. However, there are plenty of scenarios when your mirrors play an even more critical role than normal.

Mirror - Signal - Manoeuvre is part of any driver's lexicon for good reason, as failing to check your mirrors before performing a manoeuvre can have disastrous consequences. The Highway Code highlights a few occasions when mirror usage is of the utmost importance:

When overtaking, check all mirrors, and pay particular attention to the offside mirror to make sure no one is planning to overtake you.

If you need to change lane, check all mirrors as well as your blind spot.

Check all mirrors when turning right or left.

Use mirrors at all stages when approaching and on a roundabout.

Mirrors also come into play whenever you're reversing—here, you should use all your mirrors before you start, and continue to check all around while reversing.

On motorways and dual carriageways - Though motorways and dual carriageways tend to consist of long stretches of straight road, mirror usage is no less important here. Firstly, you'll need to use both your interior and exterior mirrors when joining the motorway, as well as whenever you need to change lane.

Additionally, you need to be conscious of the higher speeds present on motorways and dual carriageways, which often carry the national speed limit. This means that what's going on behind you can change in the blink of an eye—and makes regularly checking your mirrors vital.

Around other road users - It can be all too easy to forget that you're not only sharing the road with other drivers, but with also pedestrians, cyclists and animals. That's why there are specific rules regarding road users who require extra care, and of course your mirrors come into play here too.

When passing large vehicles - keep a close eye on both your interior and exterior mirrors. Note that the driver of a large vehicle may not be able to see you in their own mirrors, so give them time and room to turn if necessary.

Motorcyclists and cyclists require your attention on the road, too, as they may be difficult to spot and can weave in and out of traffic, especially in slower or stationary conditions. Keep checking your mirrors and blind spots carefully. You should also make sure that you keep checking your door mirror when overtaking a cyclist to ensure you don't collide with them or cut them off too closely. Be aware that, as your door mirror is convex, they'll be closer than they appear.


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