You should check your mirrors every 5 to 8 seconds. Checking the mirrors every 5 to 8 seconds might seem like a lot, but you can travel quite a distance in a short amount of time. The amount of distance you’ll cover when driving over a period of 5 seconds is as follows:
| Speed | Time | Distance |
|---|---|---|
| 30 mph | 5 seconds | 220 feet (67 m) |
| 40 mph | 5 seconds | 293 feet (89 m) |
| 50 mph | 5 seconds | 367 feet (112 m) |
| 60 mph | 5 seconds | 440 feet (134 m) |
| 70 mph | 5 seconds | 513 feet (156 m) |
As we can see from the table above, at 30 mph and over only 5 seconds, a large distance is covered. An awful lot can change in 5 to 8 seconds, which is why we need to check our mirrors so often when driving.
Checking your mirrors from between every 5 to 8 seconds, means when you’re driving at a consistent speed and direction. You don’t need to check all 3 mirrors each time. A brief glance, mainly in the internal rear-view mirror is sufficient, just to have a visual snapshot of what’s going on behind you. Remember, a brief glance is all that’s required as your primary observation should be ahead.
How Often Should You Check Your Side Mirrors?
Where you’re not changing speed or direction and on the open road, use mainly the internal rear-view mirror and in addition, use the side mirrors sporadically along with the internal mirror. However, you should adapt your use of mirrors and check the side mirrors more frequently when the situation is required.
For example, if you’re driving in an urban area where there’s cyclists and motorcycle riders, you should make better use of your side mirrors as cyclists and motorcyclists tend to come alongside you.
Additionally, make good use of side mirrors before a change of road layout. For example, if a single carriageway divides into lanes, or when multiple lanes merge into a single lane, you’ll need to pay much more attention to your side mirrors even if you’re not changing direction or lanes.
Along with the random mirror checks every 5 to 8 seconds, there are additional mirror checks that should be carried out before you make a change in speed or direction.
Checking the Mirrors Before a Change of Speed or Direction
Along with random mirrors check each 5 to 8 seconds, you also need to make specific mirror checks before making any change in speed or direction. This is commonly known as mirror, signal, manoeuvre.
- Speeding up: Before speeding up, you should check all your mirrors to ensure there’s not another vehicle about to overtake you.
- Slowing down: Before slowing down, you should check your mirrors just in case there’s a vehicle following you closely. If there is, you need to slow down more gradually to give the following driver time to react.
- Direction: Before making any change of direction, always first check your mirrors, then signal your intention before carrying out the manoeuvre.