This is the "Mirror-Signal-Manoeuvre" cycle. You need to know who is behind or beside you before you communicate your intent to others.
Turning or Changing Lanes: Check your rearview and side mirrors to ensure the gap is safe.
Overtaking: Verify the speed of vehicles approaching from behind in the fast lane.
Merging: Gauge the flow of traffic on the road you are entering.
When Slowing Down or Stopping
You should always check your rearview mirror before your foot touches the brake.
If someone is tailgating you, you may need to brake more gradually to avoid being rear-ended.
If you see a large HGV behind you, give them extra space and time to stop, as they require longer distances.
After Completing a Manoeuvre
When you are changing lanes on a roundabout, check over your shoulder to make sure you can see if anyone's cutting up the inside of you and use rear and door mirrors.It ensures no one has sped up into your blind spot while you were focused on the turn.
Once you’ve turned onto a new road or successfully changed lanes, check your mirrors again.
This helps you integrate into the new flow of traffic.
Stationary and Hazard Situations
At Red Lights: Keep an eye on the traffic approaching from behind to ensure they are actually stopping.
Opening Your Door: Always check your side mirror (and over your shoulder) before opening your car door into the street to avoid "dooring" a cyclist or another car.
Spotting Hazards: If you see a hazard ahead (like a ball rolling into the street), check your mirrors immediately so you know if you can safely swerve or if you must brake hard
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The "Blind Spot" Reminder
While mirrors are your best friends, they aren't perfect. Standard mirrors have physical limits.
Note: A mirror check should almost always be accompanied by a shoulder check (looking over your shoulder) before moving the steering wheel. Mirrors show you what's behind; shoulder checks show you what's right next to you
