A wave of the hand has to be one of the most simple and yet basic of human gestures.
A wave can say, “Hi,” or it can say, Thank you.”
Most important a wave to a stranger is saying “I acknowledge your existence, I am not ignoring you.
The wave immediately says, “I am friendly towards you.” Even the most hostile and aggressive of drivers, will give another driver a thank you wave, if they slow and let them in.
In fact if you don’t get a thank you wave, you feel slightly offended, somehow deprived, “Hey, I let you in and I didn’t get a thank you wave, where’s my thank you wave?”
Some cyclists will not return a wave to another cyclist, or will not do so unless they are wearing Lycra like them. Total bull-shit. I know it must be terribly hard if you are lying down comfortably on those aero bars, to struggle up to give a proper wave, but at least raise a finger or even the whole hand; make the effort.
Unless you are a serious time-trialist, or tri-athlete, it might be a good excuse to dump the aero bars. Set yourself free to sit up and wave to the whole world.
I wave to everybody when I am riding; not just people who look like me, other people on any kind of a bike, those walking, running, or on skate-boards; even ladies pushing babies in strollers. They are all people like me, out getting some fresh air, and exercise. Most times, I get a wave back but not always; I don’t feel deprived or offended if I don’t.
There are many low-income black people where I live; they ride bikes as their only means of transport. (They mostly ride on the wrong side of the road, unfortunately, so I get to greet the head-on.) I always wave and usually get a smile and a greeting back. One guy went in to hysterics and I could hear him still laughing from some distance after I passed him.
I guess my gesture was a huge source of amusement to him; at least it made him laugh, so I guess he was happy. I can hear him telling his friends, “One of those crazy white people on a bike, waved at me.”
If I see a driver waiting to turn in front of me, or pull out from a side road, I give a wave. This time it is more of an attention getter, “See me, I’m over here.” Rather like the wave to a waiter in a busy restaurant.
However, it is still a friendly gesture, and the driver may interpret it as, “Thank you for waiting, and not pulling in front of me. Often they will wave back, which is very nice; it means they have seen me, but more important they acknowledge my existence, and my right to be on the road.
A wave costs me nothing, and yet it gives so much. It gives me a great deal of satisfaction and pleasure, makes my ride a better experience.
If you are not in the habit of waving, I can recommend it. It is good for the soul, yours and your fellow travelers.