How to correctly set your car’s sideview mirrors
When I first started driving, like most people I know I set my sideview mirrors so that I could always see the side of the car. It seemed like the right thing to do. However, this leaves one with a huge blind spot, especially just off to your back left. At the time, I figured you just had to turn around to properly clear yourself before changing lanes, and I didn’t understand why we even bothered to have sideview mirrors. Fortunately, not long after I got my license, my insurance company decided to put a little set of instructions in their monthly newsletter for young drivers on how to properly set the mirrors. It turns out the car companies actually know what they’re doing with the whole mirror situation, it’s just that most of us don’t. Here’s how they’re supposed to work:
The problem with the way most people set up their mirrors is that they render the sideview mirrors almost completely redundent with the rearview (center) mirror by aiming them essentually straight back, so that you can see what’s pretty much straight behind you, including the side of your car, but not much to the side. But the sideview mirrors are actually supposed to cover very little: just the area between what you can see out the back with the rearview, and what you can see with your peripheral vision. With properly set mirrors you should be able to see everything without moving your head. You should be able to see a car coming from behind you in either lane in your rearview mirror, and as it leaves your rearview mirror it should be just coming into your sideview, and as it leaves your sideview mirrors it should be coming up directly beside you in your peripheral vision. You should thus be able to change lanes by moving your eyes, not your head.
Given differences in people’s cars (not to mention heads) the only way to get it perfect is to experiment, making sure that you never lose complete sight of a car passing you on either side. You can do this safely while stopped at a light as cars pulls up beside you, or you can adjust them while parked on the side of a street. To get a very good first approximation, do the following (this is the method USAA recommends):
- Set the rearview so that you can see straight backwards.
- Stick your head up right against the driver side window, and adjust your left sideview mirror so that you can just begin to see the left side of your car.
- Put your head in the middle of the car, between the driver and front passenger’s seat and adjust your right mirror until you can just see the right side of the car.
When you are in a normal driving position, you won’t be able to see your own car in your sideview mirrors. You’ll probably find driving like this disconcerting at first because all you can see on the side mirrors is the side of the road rushing by, with no visual reference to let you know exactly where you’re looking. In fact, you won’t be able to see anything in your sideview mirrors that you can see in your rearview. But that’s the point! If they are adjusted correctly, each mirror handles a certain angle of view behind you such that everything is covered, with no blindspot big enough for a car.
When changing lanes, all you need to do is check your rearview, and then glance to the appropriate sideview to make sure it’s not filled with car. If you just see a blur of road rushing by, you’re clear. It takes a while to learn to trust it, and for me the only way I could do so was to verify several times that I never lost sight of a passing car as I was driving.
Unlike most of my posts, this isn’t just meaningless pedantry. The whole idea is that if you have your mirrors adjusted correctly, you never need to turn your head around to change lanes, thus always keeping your head pointed where you’re going. Turning around to check what you might bump into while changing lanes is really a bad idea when it leaves you not looking at what you’re headed towards at 65 MPH.
While I disagree that most of your posts are meaningless, this one is definitely helpful in a different way. You lost me, though, on your explanation of the convex nature of the right mirror, and not just, I’m pretty sure, because I didn’t know what subtend meant. I’m still working on understanding that part.
I’m planning to try out the repositioning though, and at once was intrigued by and enjoyed the images of pushing one’s face up against the window and then bobbing it in the middle of the car there to get a starting place for the mirrors. Imagine how much disaster this could avert.
Hi Mere,
I know I didn’t explain that well. I really should add a couple of pictures to this post, but I’m too lazy. By subtend, I just mean how big the right side mirror appear to be from your vision. If you drew a triangle with one point at your eye, and the other two points at the side of the mirror, it would be a smaller angle for the right mirror than the left (since it’s further away). They have to make up for this by “fanning in” the rays of light coming in to the mirror, so that you, in effect, see much more out of the right mirror than you normally would. Probably an intuitive idea that I’ve made hopeless complicated by trying to put it into words.
Good luck with the new mirror positioning. You’ll probably find yourself changing lanes like mad now that only your eyeball needs to move. Proper mirror positioning is absolutely essential for any self respecting Masshole driver. I haven’t let a single New Jersey driver pass me yet.
Jonathan,
Thanks. I’ll actually try this next time I drive.
It’s funny how many things that seem patently obvious once you hear about them escape us for so long.
Useful tip, which I was looking for.
All well and good…but do you have to go through this rigamarole everytime you enter the vehicle. How does one confirm their mirrors have not been bumped?
I’m sticking with my mirror check and quick backwards glance upon merging….
Not that I have a rear view mirror or left mirror anymore.
You only have to do it once, unless you change cars or height.
I first learned about how to adjust your sideview mirrors from the AARP Magazine. Both of my vehicles have their sideview mirrors adjusted as you have discribed. Whenever I purchase a new vehicle, the first thing I do is to set the sideview mirrors, as I have found that I do not have any blinds spots with them adjusted properly.
I did it, and a car passed me on the highway, and it was AWESOME!!! But then I went to pass someone and still glanced to the left…
Interesting method. But one still should be aware of smaller vehicles, especially bicycles.
I appreciate your effort, but this one [ http://www.smartmotorist.com/car-accessories-fuel-and-maintenance/adjusting-your-mirrors-correctly.html ] is far better, easy to understand, simple and efficient.
However, this was one of the first things I’ve learned during driving lessons. It’s just too bad and too sad, that people who already possess a valid driving license need to be told how to do basic things, like adjusting mirrors.
It is a nice presentation, but it’s wrong. It has you setting the mirrors too close in. Also, while the picture looks nice, it’s clear that it wasn’t done accurately, as both mirrors are shown to cover the same visual angle.
I never toughed the side-view mirrors of my car since I bought it. I don’t even realize that they do exist….LOL