Originally published on: 7/29/2005 6:15:34 AM
The basic principle is that between your 2 side mirrors, center rear view mirror, normal peripheral vision and forward vision, when the mirrors are in the right position, a car is always visible in at least one of them for 360 degrees. As cars approach from behind, move lanes, etc. they just move from one zone to another. Here's a quick diagram of the overlap. It's obviously not drawn to scale or intended to be any sort of scientific measure of angles. It's just a quick sketch that reflects the setup on every car I've used it on.
To set up, either do this in your driveway or a parking lot, with the car parked. Do NOT try to set this up for the first time while on the road. Make sure the area you're working in is level and you do pretty much need another person to help you get this right. Find someone else who wants to eliminate their blind spot and take turns "being the car".
You sit in the driver's seat and have your friend go behind your car on foot at the same distance a car usually follows you (or should be following you) in the "center" of the lane. Adjust the center mirror so that you can see them clearly. Have them slowly start moving to the right. When they reach the right edge of your rear view mirror, look at the right side mirror. If you don't see them yet, adjust it until you do. Most people have their side mirrors adjusted so that they can see the physical sides of their own car. You shouldn't see your own car anywhere in the side mirrors. Now have them move forward "in the right lane" next to your car. Adjust the right mirror's vertical setup so that you see them up until you can see them out of the right corner of your eye. Repeat this on the left side.
The exact adjustments will depend on the size of your mirrors and length of your car. However, having your friend move through both "lanes" behind and come up on either side will give you all of the situations you need to properly adjust.
When you go out on the road, before looking over your shoulder check the mirrors. You may be amazed (lots of people that I've helped do this are) that when a car is in what you've always considered the "blind spot", it's actually right there in your mirror now.
Drive safe!
*Areas where a car can be behind or next to you and you can't see it without looking over your shoulder
If a car is parked at the curb, it is important for the driver to see a bicycle approaching from behind. Your recommended method to adjust mirrors does not consider that. Nor does it consider the fact that a motorcycle just behind either rear render would not be seen.
Although adjusting the mirrors too far inward is not good, you are recommending the opposite extreme and that is not good either.