To explain this a bit better from an audio engineering standpoint: the reason white noise is more effective is because, as he says, it's a broad spectrum sound that encompasses a wide range of frequencies from very low to very high.<br><br>Ever notice how if something's screeching or beeping, you can't just shout to drown it out, no matter how loud you yell? That's because your voice and the beep are resonating at different frequencies. It doesn't matter how loud or quiet either sound is, neither one will be able to drown out the other because the only way to drown out one sound is by playing a louder sound of similar frequency.<br><br>While the beeping on trucks may be effective, white noise is simply better because of how difficult it would be to drown out <b>all</b> frequencies associated with the sound. As he notes, it's a factor that allows the white noise to be played at a lower volume, not to mention a broad spectrum sound is easier on the ears than a focused, single band frequency.,(reply>), Assuming ideal conditions in a theoretical environment. Have you considered background noise or the lack of recognition of a new sound? Have you ever heard an air brake? It sounds just like it. <br>Besides, I don't know any case of someone ran over by a reversing truck with the beep.,(reply>), @Bart Vande Keere very, very incorrect.  With white noise, all frequencies are of equal amplitude. Pink noise on the other hand, is white noise with a 3dB/octave high cut filter (so the amplitude is reduced by 3dB for every octave increase in frequency). What you are referring to is band limited noise, which can be white or pink.,(reply>), We have computers everywhere now. If we can have car horns singing "La cucaracha", then we can have trucks saying "I'm backing up now, you bleep! I'm backing! I'm backing here!",(reply>), Nerd,(reply>), Kats . This is a great explanation