It’s not clear to me that most drivers use their car’s side mirrors. What is clear is that those who do often don’t have their mirrors adjusted properly. The notion seems to be that you need to be able to see the sides of your car in your side mirrors to ensure that you can see what’s alongside it.
The point was well made last year in the New York Times in Are Blind Spots a Myth? People are now spending over $1000 to purchase an option to accomplish something that can be just as easily achieved but adjusting their damn mirrors properly.
More recently Car and Driver covered the subject, complete with helpful illustrations (left). Like last year’s New York Times piece, it refers to a paper published by the Society of Automotive Engineers back in 1995. The technique is to adjust “the mirrors so far outward that the viewing angle of the side mirrors just overlaps that of the cabin’s rearview mirror.” In other words, you get a lot more benefit from your side mirrors when they don’t show you the same thing that your rearview mirror shows.
I don’t know what they teach in driver’s ed these days but when I took it, this was not something that was taught. We were taught that large blind spots are inevitable and the only way to avoid them is to turn your head at least 90 degrees before changing lanes. Admittedly, this lesson may have been a throwback to the days when many cars did not come with right-side mirrors. Oh, yes, and I did take driver’s ed in Manhattan.
Years later I learned about proper mirror adjustment on my own, though when I took advanced driver training through BMW CCA PSR, I observed it taught in practice for the first time. As the instructor put it, “You know what the side of your car looks like, so why do you need to see it in your mirrors?”