[nfb-talk] Fw: Accessible Devices (Hybrid cars article

Tue May 26 01:53:05 UTC 2009

Interesting article.
Sherri
----- 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 
>>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
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