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.4 They 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.5 For reasons having to do with the physics of sound, they also are notoriously hard to localize, further undermining their utility, says Laroche.
Robert Andres, a principal with the consulting group Environmental and Safety Associates and technical advisor for the advocacy group Noise Free America, takes a slightly different view. “I don’t believe that backup beepers are necessarily poorly designed for the job. The ‘job’ is to warn people around machinery and, in most environments they do this well by providing a sound that is unique to the surroundings, loud enough to be heard under a variety of circumstances, relatively directional, and easily understood to be a warning,” he says. “Problems arise when multiple beepers are present at a site or the alarm creates an annoyance beyond the danger zone.”
There may be no proof of harm from backup beeper noise, but there is evidence that beepers do not protect life and limb as well as hoped. An investigation by the federal Occupational Safety and Health Administration (OSHA) found that an original equipment manufacturer backup alarm failed to prevent two-thirds of backover accidents analyzed. In a vote of no confidence in backup beepers, Washington State established a requirement for a spotter at all times—someone who alerts the driver if a pedestrian steps behind the machinery. Some 183 fatal backovers are estimated to occur annually, with 44 of those attributed to nonpassenger vehicles, according to the U.S. National Highway Traffic Safety Administration (NHTSA).11
This study is on the
Environmental Health Perspectives site.
Very informative reading.
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