Press release on hybrid cars

Greetings. Following is a press release on hybrid cars I received yesterday through email. Please excuse any formatting errors and enjoy.

University of California, Riverside Press Release:

Hybrid Cars Are Harder to Hear

Quiet vehicles may pose greater risks to pedestrians, UCR psychologist finds.

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.

Preliminary results of the on-going research
project show that hybrid cars operating at
very slow speeds must be 40 percent closer to
pedestrians than combustion-engine
vehicles before their location can be audibly
detected, said Lawrence Rosenblum,
professor of psychology. Those findings have
implications for pedestrians who are blind,
runners, cyclists, small children, and others, he said.

"There is a real difference between the
audibility of hybrid vehicles and those with
traditional internal combustion engines that
could have effects on the safety of
pedestrians which need to be studied," Rosenblum
said. "Our preliminary findings could
mean that there is an added danger with hybrid
cars, particularly at intersections and in
parking lots."

In a research project funded by the National
Federation of the Blind, Rosenblum made
audio recordings of hybrid and combustion-engine
cars in a quiet parking lot. The
vehicles moved no faster than 5 miles per hour
to assure that the hybrid car operated only
with its electric motor. Subjects in a lab
listened to the recordings and indicated when
they could hear from which direction the car
approached. Subjects could make these
judgments sooner when listening to the
combustion-engine car than when listening to the
hybrid car.

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.

"This research provides evidence that hybrid
cars, when operating in silent mode, pose a
substantial risk to blind people and other
pedestrians. We hope that regulators and car
manufacturers will take notice of these results
and take steps to eliminate this risk," said
Dr. Marc Maurer, president of the National
Federation of the Blind, a 50,000-member
advocacy organization for people who are blind or have low vision.

Rosenblum, who is an adviser to the Society of
Automotive Engineers and sits on
committees that make recommendations to the auto
industry, has spent many years
researching perception of approaching cars and
whether there are similarities between
visual and auditory perception of approach.

"I really do feel this is an issue for more than
those who are blind," he said. "We're also
talking about bike riders, runners and others.
Walking around with my kids in a parking
lot makes it very clear that I'm using hearing
and vision to determine where things are."

Rosenblum is continuing the study with greater levels of background noise and
eventually will test people who are blind in
parking lots to determine the level of risk. In
April he will meet with Stanford University
researchers who are developing different
sounds that would enhance the ability of
pedestrians to hear approaching hybrid and
electric cars.

"Everyone's aware of the issue," he said.
However, Rosenblum said, "We are not talking
about major changes to the way automobiles are
designed, but about slightly increasing
their audibility when they are traveling slowly.
Only a subtle sound enhancement should
be required."