How to adjust your side/rear-view mirrors (and why you need 3 monitors)

March 19, '07 Comments [23] Posted in Musings

Typical rear-view mirror configuration

Typical rear-view mirror configuration looks something like this (please forgive the Paint.NET-ness of this rough non-vector sketch):

There's a great deal of duplication/overlap between what is seen in the main mirror versus what's in the side-mirrors.

The idea is:

Turn the side-view mirrors out so that when a car leaves the view of the center mirror, it's just begun to show up in the side mirror.
When the car begins to leave the side mirror - moving up your left side for example - it's just begun to enter your own peripheral vision.

Optimal rear-view mirror configuration

Apparently amongst car enthusiasts a well-adjusted rear-view mirror is a known deal, but it sure turned my life upside-down. It takes a while to get used to, but when you're adjusted correctly, you literally have no blind spots.

Bringing it all back home, this of course, applies to multiple monitors, IMHO. Why not fill your field of vision with as much information as possible...otherwise what might you be missing?

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Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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Comments [23]

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Monday, 19 March 2007 09:20:15 UTC

Scott, the only problem with this configuration is, depending on the way the rear pillar or A frame is set up, the rear view mirror's range can be much narrower than your 2nd diagram above.

On mine for example (mr2 spyder) the fabric of the roof comes down the sides behind the drivers head and wraps around the side to the window (no rear seats).
So if I don't keep my mirrors pretty much skimming the side of the car I have a huge blind spot up both sides of the car.
Which, as we know is exactly where cyclists and those pesky motorcyclists[1] like to hide.

I guess it's a 'your mileage may vary' (sorry about the pun) situation but for the most part makes a whole load of sense.
Of course, you can also put a little triangular mirror on the regular side mirror to cover any additional blind spots. They're pretty common in the uk but less so here it seems.

[1] Those people who like to weave in and out of traffic, cut in front of you at lights and then complain when you run them over.

That aside, I'd also recommend advanced driving courses. I was lucky enough to be taught to drive by the same guy that taught my counties police officers their tactical driving course (UK). He was pretty good, although the yanking the wheel at random times or instructing me to drive right at people in the road was a little off-putting occasionaly.
Nothing like a good skid pan course to teach you how a car behaves in a skid though. I've heard BMW's course is excellent.

Ian

Monday, 19 March 2007 10:00:49 UTC

Wouldn't it be better for BMW to fix their mirrors, rather than advocate the user fixes their behaviour?
(speaking as a 3-car owner where the BMW-developed vehicle has by far the worst blind spots)

RichB

Monday, 19 March 2007 11:05:14 UTC

Ever since I was a landscaper and driving those large landscaping trucks I have put convex mirrors on all my vehicles. You see that the trucks have all those mirrors allowing the operator to easily see everything at a glance. There should be overlap! We are talking about safety after all.

So I drive a Hybrid too, a Civic, and it has those small stick-on convex mirrors.

http://www.autobarn.net/cosami.html

They are like $2. They are always the very first purchase off the auto dealers parking lot. I feel out of control with out them.

Jay Flowers

Monday, 19 March 2007 13:37:26 UTC

I hear you on the rear view mirror thing! I've always wondered why no one ever does that with their rear view mirrors. I love being able to change lanes without having to turn my head around to see if someone is there.

Jon Kruger

Monday, 19 March 2007 14:07:01 UTC

I am skeptical about this setup for a few reasons:
1. Your drawing seems to be somewhat inaccurate. If I look in the rear-view mirror I can't see anything on the line between me and the mirror. (And I bet a car or bike fits behind my head or behind the metal between the front/rear doors.) Unless you have some crazy-wide rear-view mirror, I think you will find the field of vision (FOV) to be about 75% of what you drew, if not less.
2. This picture only demonstrates the FOV horizontally, not vertically. The rear-view mirror actually is much more limited vertically. With low objects behind you, the "overlap" from the outside mirrors can help a lot. Just imagine a kid next to the corner of your car...
3. I pretty much /always/ park backwards (because it doesn't fool your eyes). It's much easier to accurately see what's happening when using the old setup. Actually, this goes for driving in reverse in general. Not just when parking.
4. This is scary for people who actually can't drive at all. People who don't actually properly use their rear-view mirror all the time, for example when joining the highway. I bet many people ignore their rear-view mirror when doing this, whether they mean to or not.
5. It seems to me that it's much harder to anticipate with this setup. While with the old setup you can easily see stuff coming from behind early, you now much more rely on what's happening "just now".

Bringing it all back home, I say people should do the same in their cars as they (would like to) do on their desk. Just add mirrors (convex mirrors) to get more information rather than changing the kind of information. :)

Wilco Bauwer

Monday, 19 March 2007 14:11:45 UTC

By the way, for a more accurate picture see http://content.answers.com/main/content/wp/en/9/95/Blindspot_three_cars_illus.png.

Wilco Bauwer

Monday, 19 March 2007 14:24:38 UTC

I have been using this setup for years. I commute 70 miles to work. I could never go back to the standard setup. I do re-adjust my mirrors when I am in a situation when I am backing up in tight quarters. Most of the time I am driving down the road. When adjusted properly you never lose site of car when they are passing you on the left or right. The method I was taught to achieve the ideal adustment was to adjust them the same way you always did with the following differences. When adjusting the left one put your head up against the glass and when adjusting the right one lean your head in the middle of the car. This gets you in the ballpark and then you can fine tune as needed.

Bruce

Bruce Atkinson

Monday, 19 March 2007 14:37:52 UTC

I've been using this mirror configuration for 5 years now, and I couldn't drive differently. When I use my wife's car, I feel handicap. As Ian said, you must still watch out since it does create different blind spots. You still have to make sure to check them. As for convex mirrors, I'd go for a cylindrical shaped one:

http://www.autobarn.net/conwedhot.html

It's much more easy to recognize shapes and objects than with spherical convex mirrors. I prefer flat mirrors, with a realistic perspective.

As for multi-monitor setups, you can also try slimKEYS and its slimSIZE plug-in as an alternative to UltraMon (sorry I had to plug it) q;-)

Martin Plante

Monday, 19 March 2007 17:29:12 UTC

Those are some glorious diagrams. I think our side monitors are 20" - 2x2007FP and 1x30007FP

Jacob Lewallen

Monday, 19 March 2007 17:31:24 UTC

I use the same method as Bruce to adjust the mirrors and my wife hates it as she is used to looking at the side of the car as she drives along - to check it is still there????
Those monitors look very nice - I use synergy to get a similar (but cheaper) affect at one customer where the dual(crt)pc is linked to the laptop to get me three screens although it is really a virtual kwm - but it is really nice to use.

Andy

Monday, 19 March 2007 17:43:28 UTC

Scott, I was at BMW Driving School, and I agree that this is one of the most important things to learn. It takes a bit of getting used to, but makes total sense. Thanks for spreading the word!

Paul

Monday, 19 March 2007 18:59:02 UTC

Good. Something good to read here at my government job at lunch time. Will definitely adjust my mirrors on my '94 Geo Metro. It's harder than heck to be pedaling and trying to look over my shoulder.

John A. Davis

Monday, 19 March 2007 19:07:53 UTC

I apologize for the double dip here but I just remembered something I try to do when a huge oinker of an SUV rides my behind and the headlights shine right through my big back window. I take my driver side mirror and point it out and up as far as I can so that deep in my brain somewhere I KNOW that it is pointing his headlights right back into his eyes!! (or her eyes) And deep somewhere else in my brain I keep driving knowing that I haver punished and taught someone a lesson.

(and yes, I have thought of getting a whole "rack" of mirrors to put in my back window, and yes, I have thought of putting those off-road reverse headlights on my roof so I can turn them on and really punish those insesitive hogs).

John A. Davis

Monday, 19 March 2007 20:20:04 UTC

The convex mirrors are a good choice. If more than one person uses the same car, they tend to adjust the rear view mirror to their liking... and then you have to readjust it. Also, I don't trust the rear view mirror to show smaller objects in the blind spot.. like bikers.

Abdu

Tuesday, 20 March 2007 02:01:19 UTC

I got into one of my best friends car (can't remember why I was driving, we never traded cars before or since), checked the mirrors to find out all three mirrors looked the same! They were so identical that they freaked me out. I wanted to adjust them, but I was only driving for a short while, so I left them. Creepy.

My son who is a driver in the Army is mostly this way. Being my car when I discover it, I change it. Next car will definitely have the memory settings for drivers.

Me, I've got it pretty much like your second example.

Bryan Price

Tuesday, 20 March 2007 05:55:59 UTC

Why not fill your vision with more information ... ?

Because that doesn't make for more noticing.

It's a mistake in the West, compounded by Information Scientists, KM people and others who think that more information is somehow better - so they want constantly to download more, collect more etc.

Try collecting LESS - you may well notice MORE.

Turn off the TV sound, as Taleb suggests in his book Fooled by Randomness - read the paper LESS and hear the news LESS. You will probably smoooth out a lot of random (toxic as Taleb calls it) noise, and be left with underlying signals which are more important.

Don't drown yourself in noise, look LESS hard ... peripheral vision is just that - peripheral - focusing on the peripheral kills it.

regards

Michael

Michael

Tuesday, 20 March 2007 15:55:40 UTC

Not all cars have exactly the same size blind spots. My Mustang convertible has a small rear window and small rear seat windows, so the blind spots extends farther back than your drawing indicates. Adjusting the mirrors would only make matters worse. I added the convex mirrors and they work pretty well, but not at night when the headlight image appears roughly the same whether the car is 5 feet back or 50.

John

Wednesday, 21 March 2007 11:56:18 UTC

I tried this method after I read this post. It works the way you say, but it is kind of scary.
1) First problem is mentally adjusting to the change. If you have not been noticing the cars behind you for 2-3 minutes while driving, this can probably lead to some accidents if you try to use only the side mirrors while changing the lane.
2) Second, while previously you could see the car in TWO mirrors (redundant, perhaps), now you can only see it in ONE at any time and that is less reinforcing on the brain.
3) During snowstorms, the rear view mirror gets blocked because of the snowdrift and despite the heating filament on the rear window. So we have to readjust the side mirrors.

Krishna Kumar

Thursday, 22 March 2007 16:09:47 UTC

Comment for Krishna. The way mine are adjusted I see a vehicle passing me on my right or left in the side and rear mirrors. It's a nice confidence booster that you are eliminating your blind spots. Remember you don't really need your mirrors to show stuff beside you, so you may be adjusting them too much to the outside. I drive a Monte Carlo with two big blind spots when you adjust your mirrors normally. Before I started adjusting them this way, I can't tell you how many times I have started to change lanes with someone riding in my blind spot.

Bruce Atkinson

Friday, 23 March 2007 20:55:32 UTC

I don't know what kind of car you drive (or what kind of car you used for your illustration - mazda3? murano? a3?) but I'm pretty sure my rear-view mirror does not allow me to see out of my rear side windows.

That being said, I do also adjust my side mirrors further out in order to prevent the blind spot. While this does leave a space between the coverage of the side and read-view mirrors, this space is nowhere near big enough for an entire car to fit in, like a typical blind spot is when your side-mirrors are adjusted to show the side of your own car.

Luke Hutteman

Friday, 23 March 2007 21:02:21 UTC

I think your blog clock/timezone is a bit off by the way - I posted the comment above at 4:55pm Eastern Daylight Time, which I believe is 1:55 Pacific Daylight Time. Your blog shows it as 5:55pm PDT though.

Luke Hutteman

Saturday, 24 March 2007 03:33:32 UTC

Three monitors is two too many.

Joe Chung

Tuesday, 27 March 2007 04:23:21 UTC

I've had my mirrors set this way for years, I would never go back. It's not that hard to get used to, and you really can see a lot more. I rarely need to turn my head now. Even if your car has large rear pillars, you're not seeing as much as you could if you can see the side of your car in the side mirrors.

anon

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