I recently went from whistling to alert walkers on paths and roads to using a (very cheap) bicycle bell. I'm really surprised how much more effective the bell is. I think people are trained to know what the "ding ding ding" sound means. Several people just move to the side and wave without even looking back.

Now I just need to find a way to install a bell so I can get to it from the hoods or the drops. Currently I put it on my aerobars and it works ok.

If you haven't tried using a bell and often ride on bike paths, you might be surprised how useful it is.

Here is the one I got: https://www.amazon.com/dp/B08RJGWRCQ...roduct_details