[eCa]

Think relative speed. Even a bike touring cyclist will regularly travel at speeds around 40 kph (25 mph). If you then have cars travelling at 80 kph (50 mph).

Also, you learn hearing the difference in sound a car makes as it moves over to give room.

In short, I’d wager that < 0.5% of all people that have done any sort of serious biking would prefer to ride against traffic.

[dsizzle]

Per the reference in the article above (http://www.bicyclinglife.com/Library/riskfactors.htm) 8% of bicyclists were going against traffic.

Yeah relative speed goes hand-in-hand with head-on collision and less reaction time and expectation that I mentioned. I do bike a fair amount, but not on major roads. I am coming to realize that going with traffic is safer, despite it being hard to see cars coming from behind you. I also didn't realize that it's illegal in most places to bike against traffic https://roadbikebasics.com/ride-with-or-against-traffic/

[snovv_crash]

You can get mirrors on your handlebars or helmet if you lack situational awareness. I did this for my bike and it's a huge help, the Spintech drop bar mirrors are sleek and unobtrusive.

[wolverine876]

I find that focusing on the mirror, aligning it in a useful way, dealing with other issues (vibrations, etc.), and then interpreting what I see in a small mirror (which might need to be realigned to see what I need) - it all takes too long. I'm much better off just turning my head - it's faster and I have better situational awareness while I'm doing it.

Bicycle mirrors aren't comparable to automobile mirrors: Car mirrors are stable in alignment - your body is in a relatively fixed position in the driver seat and so are the mirrors relative to you and the car. On a bicycle, your handlebars are moving frequently as is your head. The whole bicycle vibrates far more than a car, sometimes making the mirrors unusable. Cars have space for more and bigger mirrors.

(Also, isn't it risky attaching anything to your helmet? In an accident, as far as I know, it can both change the helmet's performance properties and also get jammed into your head.)

[thirdsun]

I'd add Garmin's Varia radar as a better (yet more expensive) alternative to a mirror. It's a bike light combined with a radar that will track and display cars coming up behind you on your bike computer (doesn't have to be a Garmin unit since the standard is open to everyone). Many cyclists who tired it (including me) won't ride without one.

[wpietri]

Could you say a bit more about why you like it? I was thinking about getting back into touring and I just recently learned about them. Previously I was using a mirror that attached to my glasses, which seemed adequate. The radar seemed interesting, but I was concerned that it would more be in the "cute toy" category for me.

[thirdsun]

Sorry, just noticed your reply.

A lot of people consider it a cute gadget before they tried it and regard as essential safety tool once they did. It certainly depends on your use case - in busy cities it's useless since you'll be alerted to cars constantly. However in my area I ride on countless long stretches of road with little to moderate traffic. Cars will surprise you on these kind of roads. Sometimes you don't hear or notice them.

With the Varia radar I'm much more aware of my surroundings. I can take up the middle of the road until a car approaches. I won't be surprised by cars I fail to hear due to strong winds or other noise. I know when it's safe to slalom around obstacles on the street. Or when to do a left turn (I'd still look but I'm not sure if the radar ever missed a car - it's very reliable). These days I'd feel almost naked without my radar.

Plus, don't forget that it's also a very good rear light which you can control from your head unit. Don't underestimate the importance of daytime lights in order to be noticed by cars - that is the single most important measure to avoid accidents on a bike.