I looked at the "Mirrors" discussion in "Gear Talk" and I do not see the kind of discussion I present here. This is an important issue and worthy of "general discussion".
In 2006 I sent most of the following in a letter to the editor of Adventure Cycling addressed to John Schubert but I never received a reply or saw it mentioned on the website or in the magazine. As riders now prepare for a summer season of riding, and as I came across my old email, I thought I would try to start a discussion on the topic.
I am a long time bicycle commuter (now retired) and I did the TransAm east to west in 2005.
While commuting and in all other riding that I do, including the cross country ride, I have found my glasses or helmet mounted, flat, 1 inch or so mirror to be almost indispensable. Some of the reasons I like such a mirror are:
1. No false positives: If you could have a medical test that never gave you a false positive in indicating a potentially serious disease, would it be worthwhile to have it? I think so. No matter how you misuse a rear view mirror, if there is a car visible in it, you have one more piece of information about your environment that you can use in your effort to continue on your ride safely.
2. Wide view of what's behind you (to disagree with John Forester in his book Effective Cycling ): A quick sweep of the head, about what you would do if you didn't have a mirror gives you a look all across the road behind you, including the area to your right. Your normal quick view can be done with about a 45 deg turn of the head for the kind of mirror that I use. This should be enough to accomplish John Forester's interest in alerting "the drivers, because they see your head turn." With the kind of mirror that I use estimates of distance and speed are not as severely impaired as with a convex mirror such as the ones usually mounted on a handlebar.
3. Easier to use your hearing as an indicator of traffic coming from behind: Hearing is another sense that does not produce a false positive: if you hear a car or truck, it is really there. Don't trust a negative result, though: those hybrids are real quiet. I find a quick mirror check just after a car passes to be very helpful in knowing if there is a vehicle coming up from behind that you either didn't see or can't hear because of the passing one.
4. Just as when driving a car, the continual awareness of traffic both front and rear is important: I cannot see how the various arguments about possible misuse of a mirror while bicycling would be any different if applied to driving a car. For instance: "Scanning the mirror can be a distraction from the more urgent task of scanning the road ahead of you." can equally apply to driving a car. Some of the mirrors drivers use are convex and therefore objects are closer than they appear . (The best take on this was in the movie Jurassic Park where a convex mirror on a car had the warning Caution: objects in mirror are larger than they appear .)
Regarding some of the comments published in 2006 in Adventure Cycling": I don't believe you can effectively use binocular vision when looking sideways from both eyes as you must do when looking backward while turning your head. Think about it: your eyes are looking as far as they can to one side; draw a picture and note how effectively close together they are, thus reducing your binocular distance estimating ability. Why would one think that a mirrored cyclist was concentrating in the wrong direction any more than you would feel that a mirrored driver was doing so? I have John Foresters book and lived by his advice on riding in traffic when I commuted regularly but I never did agree with his conclusions regarding the use of a mirror. As I stated above, my use of a mirror still requires me to turn my head, though not as far as I would to get a full view with both eyes. I invite any rider who doesnt use a mirror to check some time just how often the rearward glance actually provides a look with both eyes directly behind you. Since I still have my peripheral vision and the mirror only covers a small solid angle of my visual field, I do not feel my forward vision is seriously compromised. As far as judging closing speed, Im convinced that the bicyclist with a flat mirror will be judging it the same way as a driver, by how rapidly the approaching vehicle is changing apparent size. Check in a car sometime and see just how often you are looking at an object in your mirror with just one eye.
I had occasion to observe riders on the TransAm who didnt have mirrors and who, because they otherwise were not paying attention, were surprised by vehicles approaching from the rear. This surprise can be evidenced by a startled reaction or by not being prepared for a gust of wind.
To sum up my position: I want as much information about my environment as is possibly available to help me make decisions about how I am going to approach the many situations that arise while cycling (or doing anything else in life). The little mirror attached to my eyeglasses or helmet provides some of that information and is well worth the little bit of fussing around and understanding of its limitations that is required to be a safer rider.
Jim Hammond
Sisters, OR
