Setting your rearview mirrors properly will ensure that you can always see what's behind your car, even if you don’t have a high-tech blind spot monitoring system or one of the new full-time rearview cameras that are hitting the market.
Is there really a correct way to position your rearview mirrors? When it comes to side mirrors, the answer is definitely yes.
Many drivers will position the mirror to show an expanse of the side of the car. Why do that? Are you afraid the rear of your car is going to vanish if you don’t keep an eye on it? What this does is it limits the field of view of the side mirror. If you tilt the mirror outward you start to see what it’s been missing, such as another car!
To position your side mirrors: Make sure your driver’s seat is where you want it and then lean slightly to the left. Look out the side mirror and adjust it so it shows just the edge of the car is visible on that inside edge. Then lean a little bit to the right and do the same on the right side mirror. What this does is it allows you to see the car if you're backing up or parking by leaning slightly, but in most cases driving straight, you get the full field of view out of both mirrors.
With this arrangement every car behind you, three lanes wide, should be visible in at least one mirror.
Also, if a car passes you on the right, as soon as it leaves that right side door mirror, it should appear in the window itself.
High-tech features are nice, but drivers should still check their blind spots regardless of features -- and adjust their mirrors properly to see all there is to see.