WHY SHOULD WE CHECK OUR RELEVANT BLINDSPOT BEFORE CHANGING LANES ?
Because there could be someone there not visible in the mirrors.
As you pass someone they may disappear from your view in the mirrors, if you then move over there could be a risk of collision.
If the chap who overtook me today, then imediately slowed a little and moved over had taken that into account, I wouldn't have had to take evasive action.
How can you know what's in your blind spot???????
By regular use of your mirrors and monitoring what has entered it and not left. You also need a brief check over your shoulder before changing lanes, very relevant whan there are more than two lanes.
For example, someone travelling in lane one of a three lane road wishing to move to lane two and just checking the centre and right mirror may not see someone in lane three moving to lane two.
Happy Christmas to you all.
Lytes Driving School