[il-talk] Manufacturers Determine Hybrid Cars Should Have Noise Generators

[Bill Reif]

It seems that much of the sighted community is beginning to agree on this 
one.


Bill

Manufacturers Determine Hybrid Cars Should Have Noise Generators
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.

www.vipconduit.com
and
www.accessible-devices.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: 
<http://mail.accessible-devices.com/pipermail/a-d_accessible-devices.com/attachments/20090525/9ad6dc29/attachment.html>
This is an Announce only list.  Subscribers are not able to post to this 
list.
To unsubscribe from the Accessible Devices list copy the line below.  Paste 
it inthe To: line of a blank message and send it.
a-d-unsubscribe at accessible-devices.com
You may download our podcasts from this link,
http://www.accessible-devices.com/Podcasts.html
Or if you're using a podcatcher of some type the subscribe URL is.
http://www.accessible-devices.com/feed.xml
Visit our website at:
www.accessible-devices.com
Please feel free to pass this message on to a friend who might like to 
subscribe.
To subscribe to Accessible Devices send a blank e mail to:
a-d-subscribe at accessible-devices.com
Just follow the directions in the confirmation message when it comes.
Please Note: Accessible Devices is not able to provide tech support for 
software or products that we supply information about.


_______________________________________________
A-d mailing list
A-d at accessible-devices.com
http://mail.accessible-devices.com/mailman/listinfo/a-d_accessible-devices.com