Lotus develops Safe&Sound hybrid system
6 Aug, 2008
6 Comments 
A third of the old stop, look and listen safety mantra became redundant with the introduction of new near-silent electric hybrid vehicles.
Lotus Engineering - yes, as in Exige - has developed a ‘Safe & Sound’ external sound system which enhances pedestrian safety for quiet vehicles.
It works by literally simulating the sound of a conventional petrol engine through a waterproof speaker mounted at the front of the car.
At low speeds when a hybrid such as the Prius would be running completely silently on its electric motor, throttle and speed dependent synthesised sound projects a realistic engine sound in front of the vehicle.
When the hybrid’s petrol engine starts operating, the control system automatically stops the external synthesis.
The system apparently fills a very real safety void, which up until this point has been the focus of many humorous hyperboles - as seen in this Clarkson review.
Whilst for the average pedestrian the idea seems almost comical, it has been mainly developed for the blind and partially blind who rely heavily on the sound of vehicles when approaching a cross walk.
“Guide Dogs believe further research and development is needed to address the issues of identifying ‘quiet vehicles’ for blind and partially sighted people. The charity recognises the environmental benefits of these vehicles however more consideration needs to be given to the safety implications to visually impaired pedestrians.”
The engine sounds were recorded using a ’suitable’ donor car which was analysed to establish the characteristic frequencies at different engine speeds.
Let’s hope Lotus has at least had a sense of humour when choosing the donor car, and dubbed the track from a Supercharged Exige - expect to hear more high performance Prius’ on the road!
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August 7th, 2008 at 7:55 am
Why not have all the electric cars equiped with “greensleeves” (as found on thousands of Mr Whippy vans nationwide). Then there would be no trouble spotting the electric cars on the road…
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August 7th, 2008 at 9:24 am
I stepped into the street the other day and almost got wiped out by a neighbour riding an electric scooter.
Damn thing frightened the life out of me, because it was totally silent.
I think I’ll make a recording of a Ducati and give it to him to use :)
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August 7th, 2008 at 10:01 am
Now this is funny, because on Sunday I was stepping out of my SUV on yet another sporting expedition to Bunnings warehouse. I was cross the crossing, like you do. But then my Jedi senses detect a presents behind me. I look round, and there it is… a pri-arse silently passes behind me. I was atleast expecting a golf cart noise, but no, nothing. So I was thinking i does need some audible noise.
Lets make it fun Toyota, how about downloadable sounds for your prius, a bit like your mobile phone. Everything from a Type-R screaming at 8000rpm to a friendly “Warning Warning I’m about to kill you”. :)
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August 7th, 2008 at 10:52 am
Bring back the road law that requires a person to be walking before the vehicle waving a red flag. (Did that law ever get expunged?)
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August 7th, 2008 at 10:23 pm
Why not just record the sounds made by an overworked 1.5L 4-pot engine?
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August 8th, 2008 at 10:47 am
Recall not long ago a mum with baby in arms walked out in front of me one night with hubby on the footpath looking on in disbelief at what almost happened.My car is not hybrid,I have a light foot in residential streets so not much noise I guess.
But headlights were on,she just did not look.
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