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The Problem of the Too-Quiet Car

In spite of a government demand for automakers to fix the problem, there is still no consensus on how to warn pedestrians of noiseless vehicles.
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Obeying the unwritten law that no good deed goes unpunished, at 8:45 p.m. the day Paris launched its fleet of 250 all-electric vehicles, one of them ran down a woman who didn’t hear it coming. The mayor’s office hurriedly assured Agence France Presse, “It is a road accident like many that sometimes happen in Paris, but at this stage no link can be made between the accident and the fact that the car was noiseless.”

Peut- être, peut-être pas, but the incident added, if not fuel then certainly electricity, to concerns about noiseless vehicles. As Eric Bridges, the director of advocacy and governmental affairs for the American Council for the Blind once told The New York Times, “An internal-combustion engine is a cue for you.”

Two years ago, the U.S. government gave automobile manufacturers until September 2017 to come up with a solution. After that date, the Pedestrian Safety Enhancement Act requires that at certain times cars make a minimum amount of noise to warn pedestrians, in particular the blind.

That does not mean there is general agreement on how to handle the problem — or even agreement that there is a problem.Anti-noise activists, for example, want less clamor, not more.

Not everyone agrees that silent vehicles present a clear and present danger. Some contend the problem is with drivers, who may be texting, talking on a cellphone, or otherwise distracted. Another camp holds that when there are more electric vehicles on the road we will be better able to hear them. Others say, in effect, that the blind should be more careful.

Still, work such as that done by the University of California, Riverside’s Lawrence Rosenblum in 2008 (conducted with the National Federation of the Blind) and the National Highway Traffic Safety Board a year later indicate that blind or hearing-impaired pedestrians were twice as likely to be hit by a “quiet car” as by a gasoline-burning automobile when the (relatively) noiseless vehicle is traveling at a low rate of speed.

On the world stage, the United Nations four years ago gathered a group of experts on vehicle noise to examine both the need for and the methods of achieving “‘quiet vehicle’ audible acoustic signaling.” The group’s 55th session occurred last month in Geneva, where amid talk of noisy motorcycles and quieter tires, experts from the U.S. and Japan offered to take on “technical sponsorship” of deriving a global regulation for making more audible vehicles.

In the meantime, a handful of carmakers have added noise, in different ways, to their quiet cars, although some observers say this has just complicated the situation.

For example, the 2011 Chevy Volt (a plug-in hybrid) makes an intermittent chirping sound, but the device is manual, meaning the driver must turn it on and can turn it off. A manual turn-off function is also found on the all-electric 2011 Nissan Leaf and that company’s Fuga Hybrid Infiniti M35; and the sound is continuous when the car is moving forward but intermittent when in reverse. The sound is continuous and automatic on the 2011 Fisker Karma and the 2011 Hyundai Sonata Hybrid, as well as Toyota’s 2012 Prius models.

California-based businessman, inventor, and engineer James F. Dunn has patented another solution — drawing from a library of sounds and either playing them through the car’s audio system or even speakers pointing to the outside world. As his patent application explains, “The microprocessor can produce the desired sound through the vehicle’s audio system in synchronization with the actual engine and drive train conditions of the vehicle being driven.” Plus, since his system plugs into a car’s existing on-board diagnostic connector, cars already tooling noiselessly down the road can make a sound.

Dunn explained that, “No one else seems to be offering a practical solution for all the [hybrid vehicles] and [electric vehicles] already on the road or for those that will be sold without a passenger warning system before the law goes into effect in 2017. The beauty of our design is its ease of installation, virtually ‘plug & play.’”

Jim Dunn, who admits to having a “deep relationship” with the “most beautiful resonance of internal combustion engines” — his first company car was a 1971 XKE V-12 Jaguar — has been racing open wheel cars for decades. He began by recording both exhaust and engine sounds of high performance cars.

“I thought buyers of electric cars might like the idea of being able to choose from a variety of exotic car sounds, but as I talked to Tesla owners, for example, I learned they loved the ‘stealth’ mode of running silent; however, Prius owners and folks who had close calls with pedestrians all said they wished the car weren’t quite so quiet at low speeds.”

While he waits for the government to specify its mandate under the Pedestrian Safety Enhancement Act (and looks for a partnering company to take his device into production), Dunn keeps his eye on what the insurance companies will do: “The data I see says that auto insurers have to be aware of the added financial exposure to bodily injury accidents caused by silent cars.”

Among the various suggestions for which sounds should be used to warn pedestrians are: bells, bird song, jet engines, and (this writer’s personal favorite) the exhaust growl of muscle-bound sports cars like Ferraris.