Mirrors and Blind Spots: The MSM Routine Explained
How to use your mirrors and check blind spots: setting mirrors, the Mirrors-Signal-Manoeuvre (MSPSL) routine and when to look over your shoulder.
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Use your mirrors well before you signal, change speed or change direction, and look over your shoulder to check the blind spot whenever someone could be hidden beside you, such as when moving off or changing lanes. The routine is Mirrors, Signal, Manoeuvre (MSM), set out in The Highway Code, and many instructors teach the longer version: Mirrors, Signal, Position, Speed, Look (MSPSL).
Poor mirror use is one of the most common reasons for failing the UK driving test, so it's worth getting right from the first lesson.
How to set your mirrors
- Interior mirror: adjust it so you can see the whole of the rear window without moving your head.
- Door mirrors: set them so you can just see the side of your car in the inside edge, with most of the mirror showing the road beside and behind you.
- Check again if someone else has driven the car or you've moved your seat.
Remember that door mirrors are often convex, which makes vehicles look further away than they are.
The MSM routine (and MSPSL)
Highway Code rules 159 and 161 describe the basic routine: check your mirrors, signal if necessary, then make your manoeuvre. MSPSL breaks it into more detail:
| Step | What you do |
|---|---|
| Mirrors | Check the interior mirror and the relevant door mirror, and think about what you see |
| Signal | Signal if it would help or warn another road user, in good time |
| Position | Move into the correct position for the manoeuvre |
| Speed | Adjust your speed, and choose the right gear |
| Look | Look all around, including blind spots, and decide whether it's safe to go |
The most important part is acting on what the mirrors show. A glance without a decision isn't enough.
When to check your mirrors
- before moving off
- before signalling
- before changing direction or turning
- before slowing down or stopping
- before changing lanes, overtaking or merging
- before opening your door
Also check them regularly as you drive, so you always know what's behind you.
Where the blind spots are
Mirrors don't show everything. The main blind spots are:
- Over your right shoulder (the driver's side in the UK), just behind the door
- Over your left shoulder, the passenger side
- Behind the windscreen pillars (A-pillars), which can hide a pedestrian or cyclist at a junction or roundabout
- Directly behind the car when reversing, especially for small children
When to look over your shoulder
Rule 159 says to look round for a final check before moving off. In practice, check your blind spot:
- Before moving off from the side of the road. Look over your right shoulder in the UK (left shoulder in countries that drive on the right).
- Before changing lanes, on the side you're moving to.
- Before merging, such as joining a dual carriageway or motorway.
- Before turning into a side road where a cyclist could be coming up on the inside.
Keep it quick: a head turn of a second or so, then eyes back to the road ahead.
Mirrors, blind spots and vulnerable road users
Since the 2022 Highway Code changes, rule H3 says drivers shouldn't cut across cyclists, horse riders or horse-drawn vehicles going ahead when turning into or out of a junction or changing lanes. That makes a final mirror and blind spot check on the side you're turning towards essential. Rule 163 also asks you to leave at least 1.5 metres when passing cyclists at up to 30 mph. Read more in our guide to the hierarchy of road users.
Common mirror and blind spot mistakes
- Signalling before checking the mirrors.
- Checking mirrors too late, after you've already started the manoeuvre.
- Forgetting the blind spot when moving off from the kerb.
- Looking but not reacting to what you see.
- Staring into a mirror for too long.
These map directly onto DVSA's top fail reasons: "not using mirrors correctly when changing direction" (number 2) and "not moving off safely" (number 3). See the top 10 reasons for failing the driving test.
Practice exercises
- Commentary drive: say out loud what you see in each mirror at every check.
- Mirror count: ask your supervisor to quiz you on what's behind you at random moments.
- Moving-off routine: practise 10 times in a row with mirrors, signal decision and blind spot check.
Summary
Set your mirrors properly, use the Mirrors–Signal–Manoeuvre routine every time, act on what you see, and check your blind spots whenever someone could be beside you. It's the foundation for safe roundabouts, motorway driving and every manoeuvre.
Practise with Co-Drive
Co-Drive is an iOS app with step-by-step driving lessons that build observation routines like MSM and blind spot checks into each skill, plus practical test practice for the GB test. It supports, rather than replaces, lessons with an instructor. See how it works.
Frequently asked questions
What does MSM stand for in driving?
Mirrors, Signal, Manoeuvre. It's the basic routine in The Highway Code: check your mirrors, signal if needed, then make the manoeuvre. Many instructors extend it to MSPSL: Mirrors, Signal, Position, Speed, Look.
Where are the blind spots on a car?
The main blind spots are over each shoulder, just behind and to the side of the car, where your mirrors don't show. Thick windscreen pillars can also hide pedestrians and cyclists at junctions.
Do I need to check my blind spot every time I change lanes?
You should check it whenever someone could be there, such as before moving off, changing lanes or merging. On motorways, a quick sideways glance is often used instead of a full head turn.
Do blind spot monitors replace looking over your shoulder?
No. Blind spot warning systems are helpful, but they can miss things. You're still responsible for checking properly.
Sources
- The Highway Code: using the road, rules 159 to 203 (GOV.UK)
- The Highway Code: introduction and hierarchy of road users (GOV.UK)
- Top 10 reasons for failing the driving test in Great Britain (GOV.UK)
This article is general guidance and does not replace official sources. Rules and prices change, so check the linked sources before you act.