I think the right side mirror is indeed meant to be used for seeing cars in the next lane over to the right, just as the left side mirror is for seeing cars in the next lane over to the left. The mirror above the dashboard is the one to use for keeping an eye on those that are behind you in the same lane you are driving in.

On “Car Talk,” the Magliozzi brothers (“Click and Clack”) explained that you should always angle the outside mirrors way, way out; that enables you to see cars coming up in the blind spots in the lanes on either side of you.

The blind spots are not such a severe issue in our cars, which have great greenhouse visibility out the windows. If you just actually turn your neck and check before switching lanes you can easily see what’s back there. But there are many cars that have very limited visibility to the rear and the blind spots can be a real problem without properly adjusted mirrors.

I never could understand why people would adjust those mirrors angled so far in that they could watch their own car. Your own car is not the car that you need to be watching. Rather, you need to be able to see the cars coming up on either side in your blind spots.