[nfb-talk] Fw: Accessible Devices (Hybrid cars article
flmom2006 at gmail.com
Tue May 26 01:53:05 UTC 2009
----- Original Message -----
From: "Parker at Vip conduit" <Vipcomm at mchsi.com>
To: "Accessible Devices" <a-d at accessible-devices.com>
Sent: Monday, May 25, 2009 12:54 PM
Subject: Accessible Devices (no subject)
> It seems that both the blind and sighted community agree on this one.
> 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
> 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
> of the vehicle. A similar idea is being explored by the European
> 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
> The researchers made sophisticated recordings of Toyota Prius hybrids
> running on
> electric power and petrol-engined cars approaching at 5mph from different
> 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
> 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
> that the brain uses to locate approaching sounds, he adds.
> Systems to do this are already being developed. Lotus Engineering, the
> 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
> 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
> out intrusive noises inside a car. Sound-cancelling works by analysing any
> 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
> 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
> to say about it. Synthesised engine noises could even help reduce noise
> says Mr. Peachey. For instance, sound from the speakers at the front of an
> 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.
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