I wave.

nothing.

I wave and say "hey!"

nothing.

I turn around, track the MF down, and get on his wheel, and cough.

nothing.

I pass him, and say "hey!" when I get along side, and pull in front.

nothing.


I stick a frame pump through his spokes.

Usually, that works.



Around here, almost everyone says hi, waves, etc.
If not, they're intent on their workout, head down.
I don't even bother waving to people on aerobars.
The majority of "others" will slow down, or turn your way, etc. if you encounter them "on the road."
You generally get close, exchange pleasantries, and then move on.

There are no commuters, so I don't know the protocol on that.