http://media-newswire.com/release_1065176.html
Quote:
(Media-Newswire.com) - RIVERSIDE, Calif. – Hybrid cars are so quiet when operating only with their electric motors that they may pose a risk to the blind and some other pedestrians, research by a University of California, Riverside psychologist suggests.
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In one study, the background sounds of two quietly idling combustion-engine cars were added to simulate the noise of a parking lot. With these stimuli, the hybrid needed to be 74 percent closer than the combustion-engine car before the subjects could hear from which direction the cars approached.
“Subjects could correctly judge the approach of the combustion car when it was about 28 feet away,” Rosenblum said. “But they could only judge the hybrid’s approach direction when it was seven feet away.” This means that a pedestrian would not be able to correctly determine the hybrid’s approach until it was one second away, he said.
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At speeds above 20 to 25 miles per hour hybrid cars likely generate enough tire and aerodynamic noise to make them sufficiently audible, Rosenblum said.
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Rosenblum changed his March 2008 results, which were not impressive, to addition of background noise, adding additional idling engines. He had to do this because his earlier results without out the background noise could easily be handled by having the blind use hearing aids.
The obvious answer is to repeat the test using bus and delivery truck noises ... and a marching band or even a boom-box car. Don't forget the low flying airplane and the screaming child. In fact, add diesel engine noises and the person talking on the cell phone. To me the real conclusion is we should eliminate the hazards of all other noises so quiet cars can be clearly heard.
Don't forget the obvious that of six blind people killed in pedestrian accidents in 2006 out of all 5,000 pedestrians and cyclists, all were struck by noise emitting vehicles. It would a terrible thing if the last sound they heard was a faux noise maker on a hybrid.
We need effective solutions to the 5,000 deaths, not more useless noise makers!
Bob Wilson