Many drivers fail to optimise rear vision because their external mirrors are adjusted so narrowly that they can see little more than the sides of their vehicle.
A driver does not need to have constant vision of the side of their own vehicle.
For correct setting, drivers should adjust the right mirror outwards so that when they tilt their head towards the driver’s side window they can just see the edge of the rear quarter panel. Similarly the left side mirror should be adjusted so that when the driver tilts his or her head towards the transmission lever only a very small portion of the car’s rear quarter panel is visible through the mirror.
These mirror settings allows the driver a wider field of vision to the rear and sides and the blind spots are minimised.
To check the setting, vehicles approaching from the rear should only be visible in the interior rearview mirror. As a vehicle overtakes it should disappear from the internal rear view mirror as it becomes visible in the appropriate external side view mirror.
It is important that the driver understands that even with this system a small blind spot still exists next to the car.
Drivers still need to use a final head check to confirm that that no vehicle is in the blind spot before merging or changing lanes.
Using these mirror settings takes time before the skills are automatic and at first it may feel uncomfortable. The benefits of this system only become apparent after continued use.