Originally Posted by
fredlord
Not sure how useful that would be in an emergency unless you have it in your mouth.
When I commuted, it was always in my mouth on one side. I cycled in downtown Toronto, so you always had to be prepared. You would think it would be uncomfortable but I just got use to it. I used that system for at least five years. Now I don't commute by bike, so no need for the whistle.
I didn't come up with this idea on my own, I saw/heard someone else use one and thought that this was way better than using a bell.