Driving Mirrors and Blind Spots


When driving, you need your mirrors to observe what is happening all around your vehicle. Most modern vehicles have three mirrors, an interior or rear view mirror and two exterior or door mirrors; one on the nearside (right-hand) door, which is the mirror nearest to the kerb, and one on the offside (left-hand) door.

When adjusting your mirrors, you need to sit in your normal driving position, to ensure that they are set up for the best possible view behind and to the sides. Adjust your mirrors so that you require the minimum of head movement to get a good view of traffic behind. A good adjustment for the exterior or side/door mirrors is to set them so that when you lean forward slightly, you can see the side of your vehicle.

The interior or rear view mirror usually has an anti-dazzle position. When driving at night, you can use the anti-dazzle to prevent being dazzled or distracted by the full beam lights of traffic behind you. When the anti-dazzle is set, although you will be able to see the light, the dazzle will be greatly reduced.

Function of Mirrors

Your driving mirrors, firstly, give you a view of the road behind you and to the sides. Secondly, they enable you to keep up to date with what is happening behind and to the sides of your vehicle. Thirdly, your driving mirrors help you to make safe and sensible driving decisions, based on the position and speed of other moving vehicles.

The information you gather from your mirrors is essential for overall safety. If when you check your mirrors you find that there is a problem behind, you may need to change your driving plans.

This forms the basis of the Mirrors – Signal – Manoeuvre (MSM) routine which is absolutely essential for safe driving. The Manoeuvre part of the routine is split into: Position – Speed – Look (PSL). See the full explanation of the MSM/PSL routine below:

The MSM/PSL – routine is fundamental to safe driving. It should be used every time you intend to change your speed or position. You must start the routine sufficiently in advance of your planned manoeuvre to allow yourself plenty of time to act on what you see in your mirrors.

MSM stands for Mirror-Signal-Manoeuvre. The Manoeuvre part is then extended to mean Position-Speed-Look (PSL).

• Mirrors – check your mirrors to assess the speed and position of traffic behind you.

• Signal – if necessary, you signal to warn other road users what you intend doing, give the correct signal.

• Manoeuvre – a manoeuvre is any change in speed or direction.

The Manoeuvre element is broken down into:

• Position – take up the correct position for the manoeuvre you are about to undertake.

• Speed – select the suitable gear and speed for the manoeuvre you are about to undertake.

• Look – look to see if it is safe to continue.

The Look element is further broken down into:

• Look – what can you see?

• Assess – what are your options?

• Decide – depending on what you can see.

• Act – either continue with the manoeuvre or wait.

Two Types of Mirror

There are two types of mirror fitted to motor cars – flat and convex. In most cars (but not all) the interior mirror is flat and the exterior or door mirrors are convex. Flat mirrors do not distort the pictures of the road behind, which makes it easier to judge the speed and distance of traffic behind you. Adjust your interior or rear view mirror so that you get the best possible view through the rear window, especially to the offside, without moving your head. When you see a vehicle in the slightly curved, convex mirror it may seem further away than it actually is. Although convex mirrors give a wider field of view than flat mirrors, the image is slightly distorted, and will make the image you see to appear to be farther away. This is why you should always use both your interior and door mirrors to get a true picture of the road behind.

To be continued

Stephen K. Dieseruvwe

Director General, Delta State Traffic Management Authority (DESTMA)

**Driver Trainer and Road Safety Consultant

**Email: sdieseruvwe@gmail.com

**Tel: +2348167814928