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Nissan adds noises to Leaf electric vehicle as safety precaution

By Peter Whoriskey
Saturday, June 12, 2010; A10

It was quiet. Maybe too quiet.

With advocates for pedestrians and the blind warning that hybrid and electric cars could catch strollers unaware, the designers of the Nissan Leaf have added sound effects to the otherwise nearly silent vehicle.

After exploring a hundred sounds that ranged from chimes to motorlike to futuristic, the company settled on a soft whine that fluctuates in intensity with the car's speed. When backing up, the car makes a clanging sound.

Nissan says it worked with advocates for the blind, a Hollywood sound-design company and acoustic psychologists in creating its system of audible alerts.

"While silence is golden, it does present practical challenges," a Nissan statement said. The Leaf is scheduled to go on sale in part of the United States in December.

Nissan added the artificial noises as lawmakers and regulators study whether auto manufacturers should be required to install warning sounds in their vehicles to alert pedestrians.

With more than 1.6 million hybrid vehicles on the road, and the number of electric cars expected to rise with the introduction of more vehicles like the Leaf, a number of safety advocates have warned of the dangers to pedestrians.

According to a study by the National Highway Traffic Safety Administration last year, hybrid vehicles are twice as likely as conventional cars to be involved in a pedestrian crash in some low-speed situations.

Others have argued that adding sounds to cars works against decades of effort by automakers to make cars that run quietly. Some electric car companies complained that silence is one of the main virtues of the battery-run cars.

Nissan's sound system is the first created by a major manufacturer. The company says it is controlled by a computer and synthesizer in the dash panel. The sounds are delivered through a speaker in the engine compartment. A switch inside the vehicle can turn off the sounds temporarily, but the system automatically resets to "on" at the next ignition cycle.

At speeds greater than 20 mph, any car, electric or not, makes significant noise because of the tires slapping on the pavement, engineers say. The noises for the Nissan operate only at the lower speeds.

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