I've never heard reversing white noise, but I have heard fire engines with sirens interspersed with white noise, for the same reasons in the video : drivers didn't know where the fire engines were.,(reply>), This is news to me too, but if it cuts down on the volume that reversing HGVs produce, I'm all for it. I lived across from a Lidl store a few years ago, and they consistently failed to switch off reversing alarms when their deliveries arrived at 3am. I'm fairly certain that it was as illegal to sound a reversing alarm as it was to sound your car horn after a certain time of night, but that didn't seem to make any difference. 