Originally Posted by Tom Bombadil

Is calling out "on your left" a cycling thing? Do cyclists say this when passing other cyclists?

I ask because I don't know why cyclists use it on a MUP for the purpose of hoping walkers stay to the right. Few walkers are familiar with the term. It isn't a phrase that any of them would ever use. When they drive cars and see someone coming up to pass them, they aren't thinking that other car is "on their left." Fact is that most people riding bikes on MUPs are short distance commuters & casual riders and they don't use the term either. I found that they don't react well to it either.

I've wondered if it is used because cyclists believe the listener is familiar with the term and knows how to react to it.