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Should electric cars make more noise?

2496 Views 3 Replies 2 Participants Last post by  Wimbledon

Popular Science said:
The Sound of Silence: A spokesperson for Fisker says the Karma, its electric sports car due out next year, will warn pedestrians by emitting a noise possibly “akin to a jet fighter.”

By 2020, one in every five cars sold in the U.S. will be a hybrid electric vehicle. That’s nice for the planet, but bad for pedestrians who can’t hear the quiet vehicles’ approach. Some automakers will equip hybrids with artificial engine sounds, but some drivers say that less noise pollution isn’t such a bad thing. Here, a cheat sheet to the noisemaker debate.
To Vroom

Experiments by psychologist Lawrence Rosenblum of the University of California at Riverside found that subjects listening to recordings of combustion-engine vehicles approaching at 5 mph—with traffic noise mixed in to simulate a parking lot—could detect its familiar rumble at a distance of 28 feet. They couldn’t detect a Toyota Prius going that speed until it was just seven feet away. The work was funded by the National Federation of the Blind, but Rosenblum says quiet cars also pose a risk to small children, the elderly, cyclists and runners.

Pending approval in Congress, the Pedestrian Safety Act would require the National Highway Traffic Safety Administration to study the minimum decibel level required to alert the blind and other pedestrians to motor vehicles, including high-end gas-powered cars. If the act is passed, the Secretary of Transportation must set a new standard within 90 days of the study’s completion, to go into effect two years later.

Not to Vroom

Traffic noise is excessive in many urban areas, and some studies suggest that long-term exposure to the din may make people more susceptible to health problems, including hearing impairment and heart attack. Cars are less dangerous at low speeds, and hybrids are silent only below 20 mph—above that, tire and air friction create enough noise to make even all-electric cars audible. The U.S. Department of Transportation has not found any evidence that hybrid cars are associated with increased accidents involving pedestrians.

A better way to protect pedestrians, some hybrid drivers suggest, is to require collision-avoidance systems or front-end airbags on all cars, although these are more complex and expensive than noisemakers. If hybrids must emit sounds, some argue, consumers should be allowed to customize them like cellphone ringtones. The company Better Place, which is developing networks for recharging electric vehicles, has already copyrighted the term “drivetones.”
What would you like your Karma to sound like? Would you like to be able to customize the sound? An option to turn the sound off?

I've come close to getting run over by a Toyota Prius driving in 'silent mode' a couple times. A distinctive sound would be helpful.
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Fisker's answer is yes.

From the NY Times:

Kevin Walsh, an engineer, monitored waves from sounds that Fisker Automotive Inc. developed to use on their hybrid car.

New York Times said:
For decades, automakers have been on a quest to make cars quieter: an auto that purrs, and glides almost silently in traffic.

They have finally succeeded. Plug-in hybrid and electric cars, it turns out, not only reduce air pollution, they cut noise pollution as well with their whisper-quiet motors. But that has created a different problem. They aren’t noisy enough.

So safety experts, worried that hybrids pose a threat if pedestrians, children and others can’t hear them approaching, want automakers to supply some digitally enhanced vroom. Indeed, just as cellphones have ring tones, “car tones” may not be far behind — an option for owners of electric vehicles to choose the sound their cars emit.

Working with Hollywood special-effects wizards, some hybrid auto companies have started tinkering in sound studios, rather than machine shops, to customize engine noises. The Fisker Karma, an $87,900 plug-in hybrid expected to go on sale next year, will emit a sound — pumped out of speakers in the bumpers — that the company founder, Henrik Fisker, describes as “a cross between a starship and a Formula One car.”

Nissan is also consulting with the film industry on sounds that could be emitted by its forthcoming Leaf battery-electric vehicle, while Toyota has been working with the National Highway Traffic Safety Administration, the National Federation of the Blind and the Society of Automotive Engineers on sounds for electric vehicles.

“One possibility is choosing your own noise,” said Nathalie Bauters, a spokeswoman for BMW’s Mini division, who added that such technology could be added to one of BMW’s electric vehicles in the future.

The notion that battery E.V.’s and plug-in hybrids might be too quiet has gained backing in Congress, among federal regulators and on the Internet. The Pedestrian Safety Enhancement Act of 2009, introduced early this year, would require a federal safety standard to protect pedestrians from ultra-quiet cars.

Karen Aldana, a spokeswoman for traffic safety agency, which is also working on the issue, said, “We’re looking at data on noise and E.V. safety, but manufacturers are starting to address it voluntarily.”

A Toyota spokesman, John Hanson, said: “I don’t know of any injuries related to this, but it is a concern. We are moving rapidly toward broader use of electrification in vehicles, and it’s a fact that these cars are very quiet and could pose a risk to unsighted people.”

A study published last year by the University of California, Riverside and financed by the National Federation of the Blind evaluated the effect of sounds emitted by hybrid and internal-combustion cars traveling at 5 miles per hour.

People listening in a lab could correctly detect a gas-powered car’s approach when it was 28 feet away, but could not hear the arrival of a hybrid operating in silent battery mode until it was only seven feet away.

Some electric-vehicle drivers have taken a low-tech approach to alerting pedestrians. When Paul Scott of Santa Monica, Calif., drives his 2002 Toyota RAV4 electric car, he often rolls down the windows along busy streets and turns up his radio so people know his virtually silent vehicle is there.

Mr. Scott, vice president of the advocacy group Plug In America, said he would prefer giving drivers control over whether the motor makes noise, unlike, say, the Fisker Karma, which will make its warning noise automatically.

“Quiet cars need to stay quiet — we worked so hard to make them that way,” he said. “It’s the driver’s responsibility not to hit somebody.”

Mr. Scott has already warmed up to the idea of a car ring tone.

“It should be a manually operated noisemaker, a button on the steering wheel triggering a recording of your choice,” he said. “It could play ‘In-a-Gadda-Da-Vida,’ or anything you like.”
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Hi ,

Animals may also depend upon audible warnings from vehicles. I would prefer a single standard noise similar to a regular engine's that comes on when speed is low and ambient noise is high. I'd love to have the back-up alarm on construction equipment turned off when motor noise is enough. They can be terrible for nearby residents.
Welcome to the Fisker Buzz forums!

steeveshephord said:
Animals may also depend upon audible warnings from vehicles.
I think you bring up an important point that you don't hear often in discussions regarding EV noise. As animals can't interpret human signage to recognize areas where cars may drive, I imagine vehicle noise may be the most important indicator animals rely on to avoid collisions with vehicles.
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