There should be a PSA because most people would just think of the sound as a vehicle releasing brake pressure,(reply>), @Michael Simpson Computer with headphones here, sounds the same.,(reply>), @Cyber Dragon Zekrom Just because people know it doesn't make it better also in rare cases as myself sounds like that can be very distracting and harmful to someone like me's thinking while a not so loud white noise is easier to deal with because it's not a loud line of noise.,(reply>), No. It sounds different when it isn't a phone speaker... Stupid,(reply>), Or just, you know, use the beep that people already know.,(reply>), Bedford TK trucks used to make a distinct noise when you applied and released the brakes.... a kind of whoosh &amp; whistle.....My uncle could do a perfect imitation of it, much to the annoyance of his nearby workmates!