Longtime TTAC commenter/contributor David Holzman has a piece in Environmental Health Perspectives entitled Vehicle Motion Alarms: Necessity, Noise Pollution, or Both? tackling the problems and effectiveness issues associated with audible vehicle warnings. He writes
For all their ubiquity, backup beepers are poorly designed for their job, and some of their most annoying attributes are part of that poor design, says Chantal Laroche, a professor in the Audiology/Speech Language Pathology Department at the University of Ottawa, Canada, who has devoted much of her career to investigating the practical shortcomings of alarm sounds. Their single tones, with a typical volume of 97–112 decibels (dB) at the source, are loud enough to damage hearing and can be heard blocks from the danger zone, says Thalheimer. Their sound is so commonplace that their warning can lose its authority through the cry-wolf phenomenon. For reasons having to do with the physics of sound, they also are notoriously hard to localize, further undermining their utility, says Laroche.
Read the whole thing.