AUG 11

Hybrids are lovable. They’re cute, kinda awkward looking and much less demanding when it comes to meal times at the fuel pump. One good thing about hybrids is also one of the bad things about these cars: they’re silent and to a concerned group of pedestrians, that silence could be very dangerous.

The National Federation of the Blind have raised their concerns about the hazards posed by hybrids, especially problematic for children, seniors and blind pedestrians who depend on the sound emitted by cars in order to travel safely and independently. The federation is calling on the industry to design an inoffensive sound that will give pedestrians a signal that a car is coming.

Two new solutions may solve the problem of too-silent hybrids. A year ago, Stanford University researchers in electrical engineering, the biosciences and sound engineering founded Enhanced Vehicle Acoustics, which markets external sound systems for hybrids. EVA’s sound system for the Toyota Prius, which runs only on electricity at low speeds, emits sounds similar to that of a regular combustion engine, but at a fraction of the sound level. When the hybrid reaches speeds of 20 to 25 mph the sound produced by the tire noise and wind generated by the car is normally sufficient for bystanders to hear so EVA’s system shuts off.

Now Lotus, one of the premier automakers in the world known for its high-performance vehicles, is also coming up with a similar technology to help give hybrids a bigger voice on the road. It’s outfitting a Prius with a waterproof speaker under the hood of the car giving it the roaring sound of regular vehicles. Lotus says its “safe and sound hybrid technology” simulates a real engine sound making it instantly recognizable that the vehicle is in motion.

To synthesize the engine sound, a road speed signal is taken from the vehicle and the waterproof loudspeaker system emanates the sound from the front of the vehicle. Once the vehicle has passed, the sound is not heard. When the car is operating on the electric motor only, throttle and speed synthesize sounds projects a realistic engine sound. If the hybrid’s engine starts operating, at higher speeds or throttle demands or lower battery levels, the control system automatically stops the external synthesis. When the powertrain control system switches the car back to running on the electric motor only, the synthesis controller instantaneously sets the system running again.

It is all completely automatic and the driver hears almost none of the additional sound. The device kicks in automatically to produce an artificial engine noise when the hybrid car runs on its electric motor. When the car's combustion engine takes over, sensors fitted to the engine and suspension turn off the sound. The engine noise is produced by a waterproof loudspeaker positioned next to the car's radiator, making the sound seem to originate from under the bonnet. The system produces a pitch and frequency designed to help pedestrians identify the car's speed and distance. Lotus adapted the system from technology previously developed to block outside noise from the inside of its cars.

Via WIRED, Enhanced Vehicle Acoustics, Lotus

Comments (18)

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This is stupid on so many levels
written by JIm, August 11, 2008

First, the streets are loud enough as it is and they want to ADD noise pollution? Second, just because someone is hard of hearing doesn't mean they should raise the sound levels of everything and make ME hard of hearing. If you hard of hearing, you probably should be walking with someone else. If I was hard of hearing, I would still think the same way, no different. Plus adding cost of the car to me because of your disablity? If you have a disability, deal with it. Don't put your responsibility on someone else. Sorry to sound cold, but that is what needs to be said.

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This is stupid on so many levels
written by JIm, August 11, 2008

First, adding noise pollution to already loud streets is dumb. Second, if your hard of hearing and walking near a road you probably should have someone with you. Third, if you have a disability don't put the burden on someone else. It's your responsibility and someone shouldn't have raise the cost of the car because of your responsibility. Sorry to sound cold, but that is what needs to be said.

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Video Story on This Topic
written by Damien, August 11, 2008

We did a story on this topic. Check it out here:

http://zaproot.com/2008/06/blind-hit-with-hybrid-zaproot-035/


Damien
ZapRoot Producer
http://zaproot.com/

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...
written by Josh, August 11, 2008

That's pretty ridiculous. We have an opportunity to rid the world of some of machine noise we create and now people are going to complain about it? That's stupid. I don't mean to be insensitive, but forcing all hybrids to integrate under-hood speakers with annoying engine noises seems like overkill to me. Not just overkill, but idiotic.

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written by dolores, August 11, 2008

Laughable. So your hybrid doesn't make enough noise to scare those pedestrians and cyclists out of your way - deal with it! - by taking full responsibility for the velocity of that hunk of junk. Don't expect to be able to take priority by force anymore. In fact I think I'll fit one of these gizmos to my bike, or my shopping trolley.

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written by Robbert, August 11, 2008

I live next to a highway. Trust me, it's not the engines that keep me awake at night. The tires however...

This is just plain silly, I know plenty of high-end cars whose engines are practically inaudible at the below 50kmh (30 mph) speeds. Nobody ever got them to fit speakers. The same applies to anyone driving downhill. Many people will idle their engine while doing that, which means that the tire-noise will obliterate any engine-noise that might escape at that point.

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written by Nate, August 11, 2008

If this happens I want to be able to change the noise that my car makes so it sounds like the Jetsons flying car.

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Irrational Fear of the Unknown
written by odograph, August 11, 2008

Why do people freak out at very small, but new, risks?

Has anyone actually been hurt by a Prius, or does it only seem new and scary.

Q1: what is the injury ratio between drunk drivers and prius drivers?

Q2: why do we concentrate on the prius rather than universal alcohol sensors?

..... because we are a bunch of monkeys.

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BTW, they aren't actually silent
written by odograph, August 11, 2008

In all electric mode a prius sounds like a golf cart.

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I'd be with the skeptics here, except...
written by Doug, August 11, 2008

I had a firsthand experience with a silent Prius in a parking lot. I was walking past some behemoth SUV which blocked my view of the corridor I was about to walk across, when I suddenly saw a Prius coming down the line, extremely close to me, requiring a hard stop on my part. I heard nothing from the car before I saw it.

It was a startling experience, and it is now easy for me to see how just a few tweaks to that situation could result in severe injury (say, the Prius driver going a bit faster, and being inattentive, and the pedestrian not looking in the right direction in time).

So I welcome this kind of change -- if it's done right. The sound shouldn't be annoying, or too loud. And shutting it off a higher speeds also makes perfect sense.

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Look both ways
written by Codesuidae, August 12, 2008

So... We should look both ways before stepping out where there may be cars?

I think I learned that somewhere once....

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written by Jacob, August 12, 2008

How can anyone claim fully intelligence and then read the article and somehow derive that blind = hard of hearing?

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creative
written by hey, August 12, 2008

It doesn't have to make the sound of an old-style car. Perhaps it could sound like something more pleasant.

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written by dolores, August 12, 2008

You people just don't get it do you? The days of being able to bully your way through a city street by encasing yourself in metal and making engine noises are over! Engine-like or not the spectacle of grown people making artificial noises to clear the way will be pure entertainment and no one will take you seriously. The end of the ICE will herald a profound change in how we get around town. Adapt and enjoy.

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Another idea
written by jh, August 12, 2008

I think they should turn this around. Make the blind person wear a necklace that receives a wireless transmission from the hybrid/EVs. When a hybrid/EV is near, their necklace will beep or vibrate; they could even make the beeping more frequent as the car draws nearer to the person.

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Ridiculous!
written by Tom Saxton, August 12, 2008

The whole premise here is completely wrong. With respect to engine noise, all modern sedans are virtually silent except when they are starting the engine or strongly accelerating.

Regardless of the type of vehicle, it's the driver's responsibility to yield right of way to pedestrians. Engine noise has nothing to do to it.

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Does that mean
written by Tim Sexton, August 13, 2008

We should put bright blinking lights on cars for the deaf? (or are those kept off for the epileptics?)

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This actually make sense
written by CA3, January 16, 2011

I can gather that some of the folks reading this might be offended by the idea of this happening, but from my own experience with electric powered vehicles, this is actually a sound issue to put into consideration. No pun intended. I'm even surprised that so many readers would have an issue with a bill that they have nothing to loose, or gain from seeing enacted.

I've used electric powered vehicles from little golf carts to warehouse forklifts and they're pretty silent running. I've usually had to honk the horn to make sure people are aware that I'm there, if they're not paying attention. If commercial electric cars are as silent running as an electric forklift, then children, seniors and blind pedestrians will inadvertently be put at risk. We've got two options in this situation, lower speed limits on pedestrian accessible streets to 20 mph, or equip electric vehicles with a way to automatically alert folks to their presence.

As things stand, equipping the car to make a little less noise then an internal combustion vehicle is just the more expedient way of solving the problem.

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