By Peter Whoriskey
Washington Post Staff Writer
Wednesday, September 23, 2009; A01
After years of trying to make cars sound as if they were riding on air, engineers are considering how they might bring back some noise. They're trying to make some of them -- those silent hybrids -- more audible.
A team of engineers developing the Leaf, the forthcoming electric car from Nissan and a front-runner in the race for a mass-market electric car, have recently been presenting their ideas for artificial noises to government officials and focus groups.
Maybe Chime No. 22?
Melody No. 39?
Perhaps a futuristic whirring like the aircraft in "Blade Runner"?
As hybrids proliferate and major automakers such as Nissan and General Motors prepare to launch battery electric vehicles next year, some automakers are seeking to address concerns in the United States and Japan that the nearly noiseless vehicles may be so quiet that they pose a threat to pedestrians.
At a meeting earlier this month and another over the summer, Nissan presented the chime, the melody and a futuristic whir to the National Highway Traffic Safety Administration, which has recently gathered evidence that the vehicles may pose a safety risk.
Regulatory committees in the United States and Japan are also studying complaints about the cars, and Congress is weighing a measure requiring vehicles to issue "non-visual" warnings to pedestrians.
"We are studying potential artificial noises that can be added to the vehicle," said Scott Becker, a Nissan senior vice president.
But the nascent industry is divided over whether safety sounds should be added to the quiet cars and, if so, what those noises should be.
"Frankly, we've been working for 30 years to make cars quiet -- never thinking they could become too quiet," said Robert Strassburger, vice president for vehicle safety at the Alliance of Automobile Manufacturers, an industry group that has been working to address the concerns. But now "those vehicles may be difficult to detect."
Hybrid vehicles typically operate on hushed battery-powered electric motors when idling and traveling at low speeds. At higher speeds, the noisier internal-combustion engine kicks in. Toyota, which makes the popular hybrid Prius, a small car that runs very quietly at low speeds, does not add artificial sounds.
Cars like Tesla's Roadster, Nissan's Leaf and General Motors' Volt, which will depend on battery electric power, may be even quieter.
Officials at Tesla say they have no intention of implementing "fake noises." The company already makes the $109,000 electric Roadster, a luxury product popular with eco-conscious celebrity customers.
"We have delivered more than 700 cars, and our customers overwhelmingly say the relative quiet of the powertrain is one of the most appealing aspects of the car," said Tesla spokeswoman Rachel Konrad. "Thanks to widespread electric vehicle adoption, we will all enjoy far less noise pollution in the future."
Evidence that the hybrid sales spurt poses a safety threat has been scant, in part because the phenomenon is new and the hybrid cars represent only a small fraction of the more than 230 million vehicles on the road, transportation officials said.
But an as-yet-unreleased NHTSA study of accidents in 12 states compares accident rates for some hybrid vehicles and their internal combustion engine counterparts.
Covering more than 8,000 hybrid electric vehicles and nearly 600,000 gasoline-fueled cars, the analysis suggests that during certain low-speed maneuvers such as turning and backing up, hybrid vehicles are 50 percent more likely to be involved in an accident with a pedestrian, said Ronald Medford, acting deputy administrator of NHTSA.
"We certainly know that blind pedestrians rely heavily on the sound of vehicles as a means of determining when it is safe to cross the road," Medford said. "But all of us are susceptible."
The potential problem arises at speeds less than 15 mph, when the electric and hybrid vehicles are notably quiet, almost silent. At higher speeds, the rush of air and the slap of tires makes the electrics almost as noisy as their gasoline-powered counterparts.
Rep. Edolphus Towns (D-N.Y.) has introduced a bill that would require the Department of Transportation to establish a safety standard under which cars would have to be equipped to issue "non-visual alerts" so that pedestrians can determine the vehicle's location, motion and speed.
It has garnered 139 sponsors, among them Cliff Stearns (R-Fla.), who says he has been startled by a quiet car.
"I was down in Florida in the parking lot of a shopping center, and I was wheeling my groceries with my wife, and I didn't hear a car come up behind me," Stearns told reporters. "If all the cars are silent in the future, it does pose a problem."
But if electric cars are to be equipped with sound, there is little agreement over what the sound should be, how loud it ought to be and whether manufacturers should be allowed to create their own distinctive audio tracks.
Some automakers are already experimenting with or planning to develop noises.
The Fisker Karma, a luxury electric vehicle, will have an integrated audio system that will both alert pedestrians and give the car a "distinctive audio signature" that will be "reflective of the car's advanced technology," a spokesman said.
Officials with the National Federation of the Blind, which has pressed the safety issue with automakers and regulators, have advocated that electric cars make sounds similar to those of gas-powered cars.
"Society is conditioned to that sound," said John Par?, director of strategic initiatives for the group.
There is some concern that if a variety of noises are permitted, then electric cars could merely add another layer to the urban cacophony, potentially conflicting with state and local laws governing decibel levels.
"If we all do it differently, we will confuse the heck out of the consumer,'" said Nancy Gioia, director of hybrid and sustainable technology at Ford.
Nissan declined to release the audio tracks being considered but said it would make its final decision in consultation with regulators.
It is also seeking approval from drivers, some of whom have been fussy about the various sounds tested.
"They are too flat and irritating in hearing for more than even five minutes," one respondent in a Nissan test said.
"Monotonous sound makes me sleepy," said another.
Said Par?: "We are certain that there is a safe level of sound that isn't burdensome to society."