Students' prototype counters quiet creep of hybrid cars
From: Stanford News Service - 05/28/2008
By: Massie Santos Ballon

Graduate students Everett Meyer, in the School of Medicine, and Bryan Bai, in
the School of Engineering, have invented a system that emits sounds from
small speakers intended for mounting to the exterior of hybrid vehicles. 

The problem is that hybrid vehicles running on electric motors are moving so
quietly that pedestrians, especially blind people, can't hear them. Last
month federal lawmakers introduced a bill called the Pedestrian Safety
Enhancement Act of 2008. If the bill passes, the Department of Transportation
will do a study to establish minimum sound levels for all hybrid vehicles,
whether they're idling, speeding down the freeway or slowly making their way
through parking lots and residential streets. Prius owners are debating the
bill they call the "Bell the Hybrid Act" in online chat forums across the
nation. 

Their PANDA system, Meyer said, is about 5 decibels quieter than a regular
combustion engine from the front and 10 to 20 decibels quieter from the back.
They're working on a commercial version of PANDA they hope to have ready by
early June. (PANDA stands for "Pedestrian Awareness Noise-emitting Device and
Application.)  

The sound comes from small speakers the size of one's palm installed in the
front wheel wells and under the back bumper, said Meyer. They can handle all
weather conditions and a wide temperature range, he added. 

In October, they demonstrated the PANDA speaker system at a convention of the
California chapter of the National Federation of the Blind. Driving by a
group of blind people, Meyer and Bai played two different sounds on the car's
speakers. One sound mimicked diesel engine noise, the other a diesel
accompanied by higher-pitched pinging. 

"Universally, the blind people didn't like the pinging noise," Meyer
recalled. "They thought it was distracting even though they could hear it
better."  

Read the entire article at:
http://news-service.stanford.edu/news/2008/may28/prius-052808.html

View a video at:
Graduate students demonstrate the audible Prius
http://news-service.stanford.edu/news/2008/may28/videos/331_flash.html

Links:
National Federation of the Blind
http://www.nfb.org/

Enhanced Vehicle Acoustics
http://evacoustics.com/

UCR research shows dangers of hybrid cars to visually-impaired pedestrians
http://www.pe.com/localnews/inland/stories/PE_News_Local_D_blind05.35c9684.html

Stanford students make silent cars noisy
http://www.paloaltoonline.com/news/show_story.php?id=8211

Stanford graduate students solve the silent Prius problem
http://blogs.spectrum.ieee.org/tech_talk/2008/05/stanford_graduate_students_sol.html

Are hybrids too quiet?
http://features.csmonitor.com/environment/2008/05/29/are-hybrids-too-quiet/

The Whistle's Go Woooooo!
http://www.youtube.com/watch?v=YK18wQA-tHs

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Nearly Silent Hybrid Cars May Endanger the Blind
-http://www.npr.org/templates/story/story.php?storyId=7555520

How Many Blind People Have Been Hit By A Prius?
-http://www.treehugger.com/files/2008/04/how-many-blind-people-hit-by-prius.php

NHTSA to Hear 'Silent Killer' Complaints
-http://www.consumeraffairs.com/news04/2008/06/prius_nhtsa.html

Blind People Say Nearly-Silent Hybrid Cars Pose Safety Risk
-http://www.foxnews.com/story/0,2933,299079,00.html

Blind pedestrians protest quiet hybrid cars
-http://rawstory.com/news/2007/Blind_pedestrians_protest_quiet_hybrid_cars_1004.html