Properly adjusted car mirrors should show a specific, limited view of your own vehicle and a wide view of adjacent lanes to virtually eliminate blind spots. The goal is to create a seamless transition between your rearview and side mirrors, minimizing the area where other vehicles can disappear from sight.
A correctly set up rearview mirror should frame your entire rear windshield. You should not see the sides of your own car or the tops of the rear headrests unless they obstruct your view. Its primary function is to monitor traffic directly behind you over a long distance.
The side mirrors are where most drivers err. The common, outdated method of seeing your own car’s flank in the mirror creates a significant blind spot. The modern, recommended technique is to lean your head until it almost touches the driver’s window, then adjust the left side mirror outward until you can just barely see the rear corner of your own car. When you return to a normal driving position, your vehicle will occupy only a tiny sliver of the mirror’s inner edge. For the passenger-side mirror, lean toward the center console and adjust it outward until your own car is just barely visible. This setting provides a much wider view of the lane beside you.
Industry studies, including those by the Society of Automotive Engineers (SAE), have validated this approach. When mirrors are set this way, a vehicle passing you will transition smoothly from the rearview mirror to the side mirror and then into your peripheral vision, with no point where it completely disappears. This method can reduce the traditional blind spot area by over 90% compared to conventional mirror settings. The table below summarizes the key visual reference points:
| Mirror Type | What You Should See (Correct Setting) | Common Mistake |
|---|
| Rearview Mirror | The entire rear windshield and the road beyond. | Including roof liner, headrests, or your own car’s rear seats. |
| Driver’s Side Mirror | The horizon centered, with your own car only barely visible as a reference sliver on the inner edge. The rest is the adjacent lane. | A large portion of your own car’s side, duplicating the rearview mirror’s view. |
| Passenger Side Mirror | The horizon centered, with your own car only barely visible on the inner edge. A wider view of the road to the right. | Angled inward to see your own car, creating a massive right-side blind spot. |
While this “wide-angle” setting feels unusual initially, it is vastly safer. It requires trusting the mirrors and relying on the rearview mirror for what’s directly behind. For lane changes, a quick glance at the corresponding side mirror is sufficient, though a final over-the-shoulder shoulder check remains a critical, non-negotiable safety step to cover any remaining minimal blind spot and account for motorcycles or fast-approaching vehicles.
Remember to readjust all mirrors every time your seating position changes significantly. The view is highly sensitive to your eye position. Consider your mirrors as a system: the rearview covers the center, and the side mirrors cover the flanks, with minimal overlap.
