Weird, I've been driving lorries for 12 years and never had one with a white noise reversing alarm. My most recent vehicle is a 12 plate, so seven years old now, (only 2 years old when this video was published) and had a standard high pitched tone reversing alarm. And when it was malfunctioning, it was replaced with BackAlarmᵀᴹ which also had a high pitched tone (although slightly lower than the original, and louder) not white noise.