[nfbwatlk] FW: [Caps] Fw: Economist article on our hybrid research

Mon May 11 23:56:48 UTC 2009

Great article! Me, I want one of those thundering mighty V-8 engine 
packages! Glass-packs forever!

Mike

----- Original Message ----- 
From: "Nightingale, Noel" <Noel.Nightingale at ed.gov>
To: <nfbwatlk at nfbnet.org>
Sent: Monday, May 11, 2009 11:26 AM
Subject: [nfbwatlk] FW: [Caps] Fw: Economist article on our hybrid 
research

Economist article on our hybrid research

Link also included.

  The sound of silence
  Economist - UK

Economist

Electric cars and noise

The sound of silence
May 7th 2009
>From The Economist print edition

Sound generators will make electric and hybrid cars safer

WHEN cars run on electric power they not only save fuel and cut 
emissions but also run more quietly. Ordinarily, people might welcome 
quieter cars on the roads. However, as the use of hybrid and electric 
vehicles grows, a new concern is growing too: pedestrians and cyclists 
find it hard to hear them coming, especially when the cars are moving 
slowly through a busy town or manoeuvring in a car park. Some drivers 
say that when their cars are in electric mode people are more likely to 
step out in front of them. The solution, many now believe, is to fit 
electric and hybrid cars with external sound systems.

A bill going through the American Congress wants to establish a minimum 
level of sound for vehicles that are not using an internal-combustion 
engine, so that blind people and other pedestrians can hear them coming.
The bill's proponents also want that audible alert to be one that will 
help people judge the direction and speed of the vehicle. A similar idea 
is being explored by the European Commission.

Although there is little data on accidents, the latest research suggests 
there is cause for concern. Vehicles operating in electric mode can be 
particularly hard to hear below 20mph (32kph), according to experiments 
by Lawrence Rosenblum and his colleagues at the University of 
California, Riverside. Above that speed the sound of the tyres and of 
air flowing over the vehicle start to make it more audible.

The researchers made sophisticated recordings of Toyota Prius hybrids 
running on electric power and petrol-engined cars approaching at 5mph 
from different directions. These were played to a group of subjects 
wearing headphones. The subjects were asked to press one of two buttons 
to identify which way the vehicle was coming from as quickly and 
accurately as possible. As expected, they could determine the direction 
of the petrol-engined cars much faster. When natural background sounds, 
like the engine tickover of a parked car, were added, the hybrids'
direction sometimes could not be detected until they were perilously 
close. Both sighted and blind subjects gave similar results.

Beep, beep

Dr Rosenblum and his colleagues recently repeated the experiment outside 
in a car park. This time blindfolded subjects stood three metres away 
from the point where the vehicles passed. The researchers found that the 
hybrid vehicles had to be around 65% closer to someone than a car with a 
petrol engine before the person could judge the direction correctly.

What sort of noise should electric-powered cars make? They could, 
perhaps, beep as some pedestrian crossings do, or buzz like a power 
tool. Having worked with blind subjects, Dr Rosenblum is convinced of a 
different answer: "People want cars to sound like cars." The sound need 
not be very loud; just slightly enhancing the noise of an oncoming 
electric vehicle would be enough to engage the auditory mechanisms that 
the brain uses to locate approaching sounds, he adds.

Systems to do this are already being developed. Lotus Engineering, the 
consultancy of a British sportscar-maker, recently signed an agreement 
with Harman Becker, a producer of audio systems, to commercialise one.
Lotus has worked on a number of hybrid and electric vehicles and it was 
while these were moving around its factory that the engineers thought 
they would be safer if they made a noise.

The system Lotus uses was originally developed for a different reason:
to cancel out intrusive noises inside a car. Sound-cancelling works by 
analysing any unwanted frequencies and then producing counteracting 
ones. The Lotus system was adapted so that it could also produce sounds 
that change with speed and use of the throttle, providing a familiar 
audible "feedback" to drivers of vehicles with a silent engine. Adding 
external speakers allows pedestrians to hear the noise too.

It is possible to create a different sound within a car from the one 
that is heard outside, says Colin Peachey, a chief engineer with Lotus.
Manufacturers could create their own sounds according to how they 
perceive their models. Carmakers already take engine noises seriously 
enough to use acoustic engineers to tune exhaust pipes, especially for 
high-performance cars. Drivers of electric cars might in future even be 
able to select different engine sounds, and maybe download them like 
ringtones.

Although some drivers might want to cruise in an electric car thundering 
to the sound of a mighty V8 engine, it is not necessary-and traffic 
police may have something to say about it. Synthesised engine noises 
could even help reduce noise pollution, says Mr Peachey. For instance, 
sound from the speakers at the front of an electric car (or the rear if
reversing) is highly directional. This means it is more likely to be 
noticed by pedestrians in front or behind the vehicle. The noise from an 
internal combustion engine, however, radiates in many 
directions-including upwards into offices and bedrooms.

Unique engine noises would still be possible. A sound-generator will be 
fitted to the Fisker Karma, a luxury plug-in electric hybrid which goes 
into production later this year. It will both alert pedestrians and 
enhance the "driver experience", says Russell Datz of Fisker, based in 
California. As the Karma uses new technology it is fitting that its 
sound should also be new, he adds. But Fisker still has to decide what a 
luxury electric car should sound like.

--
Lawrence D. Rosenblum
Professor
Department of Psychology
University of California
900 University Ave.
Riverside, CA 92521
USA
Office: 951-827-4400
Cell: 310-903-3079
FAX: 951-827-3985
rosenblu at citrus.ucr.edu
http://www.faculty.ucr.edu/%7Erosenblu/
Laboratory demonstration page:
http://www.faculty.ucr.edu/~rosenblu/lab-index.html
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