In 2007 the National Federation of the Blind reported that hybrid cars, because they make little noise at slower speeds, posed a hazard to blind pedestrians
"I'm used to being able to get sound cues from my environment and negotiate accordingly. I hadn't imagined there was anything I really wouldn't be able to hear," said Deborah Kent Stein, chairwoman of the National Federation of the Blind's Committee on Automotive and Pedestrian Safety. "We did a test, and I discovered, to my great dismay, that I couldn't hear it."
Now two Stanford University graduate students have solved that problem by creating a soft, high-pitch hum that can be heard when the silent electric motor of the hybrid is engaged.
Everett Meyer, co-founder of Enhanced Vehicle Acoustics, who will graduate next week with an M.D./Ph.D. degree in immunology, and fellow founder Bryan Bai, who also will graduate next week with a Ph.D. in electrical engineering, say that adding the sound is a public safety issue, especially for blind people who use their hearing to maneuver.
The Palo Alto Daily News says the California blind community already supports their invention.
"The specter is that any time you cross a street, you don't know if it's safe to cross. ... That's a fundamental change that's happened only in the past few years,'' said Brian Bashin, a member of the California National Federation of the Blind's Quiet Cars Committee. "In the previous 100 years, cars have always made enough noise.''
The patent-pending system designed by Meyer and Bai still will be quieter than most gasoline-engine cars.
"At less than 50 decibels, the sound is practically inaudible inside the car. But the system externally emits a soft engine noise from four speakers attached to the vehicle's front and rear," the Daily News reports.
The sound system plugs into the hybrid's computer system and takes less energy than a car radio.
