I've never been particularly effective at whistling. Some people can't whistle -at all-, I produce a shallow 'blowy/breathy' whistle, which has about 1/4 of an octave range. That article describes the ...

Forget that pitiful bell. On loud and busy streets, you’re gonna want one of these. There’s a reason why car horns are so annoyingly loud: If you need to get a driver’s attention in an emergency and ...