How to Adjust Your Mirrors So You Actually Lose the Blind Spot

Most drivers set their side mirrors the same way, angled so they can see a slice of their own car's rear quarter panel in the frame, because that is how a parent or an instructor showed them years ago. It feels reassuring to see part of your own vehicle in the mirror. It is also the single biggest reason blind spots exist in the first place, and changing how you set those mirrors eliminates most of the problem without buying a single extra piece of equipment.

Why the traditional mirror setting creates the blind spot it is meant to prevent

When a side mirror is angled to show your own car's body, it duplicates the field of view your rearview mirror already covers. The rearview mirror sees directly behind you, and a side mirror set the traditional way sees a slightly wider version of roughly the same area. Between the outer edge of that overlapping view and where your peripheral vision takes over looking out the side window sits a gap, the classic blind spot, where a car can sit for several seconds completely invisible to you unless you physically turn your head.

This setup is not a design flaw in the car. It is simply a widespread habit in how people set their mirrors, and it has been studied and written about by driving safety researchers for decades without the habit itself changing much in general practice.

The method that actually closes the gap

The fix, sometimes called the SAE mirror setting method after the engineering society that studied it, is simpler than it sounds and takes about a minute to set up. Start with your rearview mirror adjusted normally so it frames the full view out your back window. For the side mirrors, lean your head toward the side window until it nearly touches the glass, then adjust that side mirror outward until you can just barely see the edge of your own car in the frame from that leaning position. Repeat the same process on the other side, leaning toward the centre of the car this time.

When you sit back upright in your normal driving position afterward, your own car's body will have disappeared from both side mirrors entirely. That is intentional and correct, not a mistake to fix. The rearview mirror is already covering the view directly behind the car, so the side mirrors no longer need to duplicate it.

Why this setup feels wrong for the first few drives

Almost everyone who switches to this method reports a brief period, usually just a few drives, where the mirrors feel oddly angled because they no longer show any part of the car itself, which most drivers have unconsciously relied on as a reference point for years. This discomfort fades quickly once you start noticing cars appearing in your side mirrors that would previously have vanished into the gap between mirror and peripheral vision, which tends to convert sceptics fast once they see it working in real traffic.

A simple way to test whether your new setting is actually working

Once your mirrors are set this way, test them safely in a quiet area or with a passenger helping. As a car passes you on the highway, it should appear in your rearview mirror, then hand off smoothly into your side mirror's view before you can see it in your peripheral vision looking out the side window, with no gap where it disappears entirely. If a car vanishes from view for more than a second or two during that handoff, the mirror on that side is probably not angled quite far enough outward and is worth adjusting slightly more.

This handoff test is worth repeating occasionally, particularly after anyone else has driven the car and potentially bumped a mirror back toward the traditional setting without realising why it had been changed.

This method reduces the risk, it does not eliminate checking entirely

Properly set mirrors dramatically shrink the blind spot but do not claim to eliminate every possible gap in every situation, particularly with larger vehicles, trailers, or unusual lane configurations. A quick glance over your shoulder before a lane change remains good practice on top of correctly set mirrors, not a substitute for them. The combination of both habits together is considerably safer than either one alone, which is worth keeping in mind particularly on a long road trip, where hours of unfamiliar highway driving add another layer of risk on top of normal blind spots.

Nighttime glare is a separate adjustment worth knowing about

Many vehicles have a day and night setting on the rearview mirror, a small lever at the base of the mirror, that tilts the reflective surface to reduce headlight glare from cars behind you after dark. This is unrelated to the blind spot fix above but is worth checking if you have never used it, since a lot of drivers go years without realising their mirror has this feature built in.

Shared and borrowed cars tend to drift back to the old setting

A car driven by more than one person, a family vehicle, a borrowed car, or a rental, tends to drift back toward the traditional mirror setting over time as different drivers nudge mirrors toward what feels familiar to them. It is worth checking your mirrors with the lean-in test described above periodically, particularly after someone else has driven the car for a while, rather than assuming a setting adjusted once will stay correct indefinitely. For anyone who regularly switches between vehicles, such as a rental on a trip, taking the minute to reset the mirrors properly in each new car is a habit worth building rather than skipping because it feels like a small, unnecessary step.

A free fix that takes less time than reading this article

Unlike most safety upgrades, this one costs nothing, requires no tools, and takes about a minute per side to set up properly. Given how much time most people spend driving, and how often lane changes and highway merging put blind spots directly in play, it is one of the better returns on a small amount of effort available to any driver. Pairing it with the habits covered in our road safety section rounds out a more complete approach to the small, free changes that genuinely reduce real risk on the road.