Acoustics & Audio Technology

What are the decibel noise differences between an EV and say a Lexus sedan rolling down a city street? I have noticed a number of cars that the engine is so quite that you can hardly hear it. Predominantly, the tires are the noise makers and you need to be going with some speed.

However, that may be a mute point (no pun intended) since many cars have their stereos turned up so loud that even the deaf can feel them coming.

Still, the only case I can see is an issue is for the blind and I am weary of that claim a little because there are still bicycles racing down the street.. Clearly, if you have functioning eyes, then I can't see an excuse for not looking out for yourself.

Another GA for the Anonymous Hero. Truly it is the tires that make the most noise on most of todays vehicles. If you are deaf and blind out on the street you are looking for trouble.

That said, it is still the drivers responsability to look out for pedestrians and any other obstructions. Accidents do happen, however. Some unthinking pedestrian, perhaps distracted by the music from thier Ipod, perhaps stumbling out of the local bar having had one too many.

We, in this society, seem bent on trying to protect everybody from everything. Perhaps we should all be wrapped in bubble wrap.

I agree with Shadetree. 99.5% of the people are already inconvienced 99.9% of the time by having to park farther away from stores and businesses bypassing parking spaces that are never used, having to bend over way too far to get a drink of water at public water fountains and making sure we men have really accurate aim trying to hit too low urinals in the Men's Restrooms. Now we have to put up with annoying noises just because we are trying to save on gas by using electric powered cars.

#1. The 50-90% of motorcyclists (and a few cars, trucks of all sizes) are louder then legal, i.e. many straight pipes. This is in the US & Canada.

Someone from that group is who put this subject up for discussion, i.e. deja vu, seen this before. They said the Model T would frighten the horses with all the noise it made.

Those of us who enjoy riding a motorcycle for the sake of riding a motorcycle do it quietly.

There are those who want to make obnoxious noise and use a motorcycle (car, truck)to do it.

An electric car ( www.teslamotors.com ) or performance car needs to make noise like adding playing cards to the wheel spokes of a coasting stock Corvette.

The driver of the vehicle is responsible for avoiding pedestrians, deer, squirrels, policepersons and police cars, other vehicles abandoned in the roadway, construction sites, rubble from hillsides, flooding, collapsed bridges, potholes, poorly marked exits and highways,... and driving safely while having access to the radio, cell phone, GPS,...

I can't remember the last time I saw a blind person cross the street, I've been in 25 states and 8 Canadian Provinces this year.

Great discussion. Bikers & Hotrodders have been saying " LOUD PIPES SAVE LIVES" for years

It is not that electric vehicles are that quiet, as the other respondents have already said, tire noise is still heard. The problem is the combination of loud noise from trucks, busses, and other loud noises that drown out an electric vehicle in the city. To add a sound will only make the noise pollution in the city worse.

What needs to be done is a positive move in the right direction by identifying and reducing the excessive noise from other sources.

Any solution will help:, designated truck routes and times, electric public transportation, smaller busses etc,etc.

In problem solving the first step is to identify the root of the problem. A quiet vehicle is not a problem. Noise is the problem.

Instead of adding to the problem, fix it!

In fact the only people that are calling it dangerous is the current auto industry that has no vision. Instead of converting their vehicles to electric drive, they spend all their time finding reasons not to. Talk about a bad case of resistance to change. These are the same people that have spent billions in making the IC engine quiet!

The funny thing is that they refuse to change because they think they make more money in IC parts and oil. How much money will they make when they are bankrupt and the whole world has backlashed against them!?

How true. Have to be especially careful in supermarket parking lots. If only one could attach motor from the Black& Decker electric lawn mower, pedestrians would stay out of the way. Love that car, though. Kelsy

One good reason to only cross at crosswalks.

Like an automatic garage door or a fighter jet, they should be designd to automaticly brake and/or steer to avoid collision. Naturally this would cause accidents if all traffic didn't adhere to the same standard.

Anyone concerned could carry a reciever designed to warn them of the presence of any vehicle, but this would be a stop-gap, pragmatic approach since it is the drivers responsibility to yeild to pedestrians. Preserving that responsibility important.

Pedestrians should look both ways before crossing.

If I hit somebody because they do not look both ways, etc., I know I will not play the blame game but live with the horror of it for the rest of my life.

It seems to me that peds are and have always been in danger of getting run over by even very loud cars, trucks, bikes, etc, so therefore, adding sound to quite cars is not going to change the rate of car to ped accedents at all. Just my thoughts on it.

But what the hell, one more mommy law, faily soon we will not be able to go outside of our house without full body armor with brain bucket on.

This is just another attempt at putting seat belts on motorcycles.

No science, no engineering, no reallity. Appears as if belief (the lowest form of knowledge) is running the gov, country, and world.

Dangerously silent vehicles, BMW motorcycle. At least electric drive cars have a high pitch whine.

I didn't see mention in of any of the responses as to whether or not the writers had actually DRIVEN a SILENT vehicle. Silent at a cross walk etc. at least.

I have - Several versions of the Plug-In EV1. The later versions of it were well into the "real car" usefulness range - but pedestrians REALLY DO WALK RIGHT INTO A BRIGHT RED CAR when it is totally silent when stopped. Honest - it's weird.

The EV1 had a neat little "solution" to this problem that was really fun to use... Below 5mph using the high beam flasher would produce a moderate "Meep Meep" on the horn. It sounded for all the world like the Warner Bros "Road Runner."

Any of you who believe this isn't a real phenomenon should try driving a truly silent car. Quiet ICE are NOT the same - they are quite far from silent.

As to the question of absolute DANGER- that's maybe different. It's just the danger of someone waling into the side of your car, while looking straight ahead... They fall onto your hood and drop their coffee all over it. Messy, but maybe not terrifically dangerous.

The bleeting horn seemed like an appropriate level of mitigation.

Bleeting the horn when someone was about to walk into the car was quite funny. The looks on people's faces as your bright red car appeared out of nowhere were priceless. They'd just stop and stare in bewilderment.

So, Bleet Bleet to those of you who are doubting this issue! It's right in front of you!

This may well be a bit of a "red herring" problem in that most pedestrian accidents may have nothing to do with the noise or lack of generated by the vehicle, and which the actual amount of money spent per life saved could be in the many millions. But still, presuming a noisy car making does save injuries and lives over a quiet one, safety is always important. I'm in favor of an "active" solution because it would: 1. not (usually) make noise unnecesarily, and 2. make more work for engineers.

Sound from a "quiet car" need only be generated when there is someone nearby who might be in danger if they didn't hear it. Some of the latest cars already have detection of slow-moving vehicles directly ahead which sounds an alarm to the driver, and at the last moment applies the brakes to prevent an accident. Modern technology should detect a pedestrian or bicyclist at a significant distance (perhaps 100 feet) ahead, which could then activate an external sound generator to alert then a car is coming. It would be better to simulate engine and exhaust noise rather than blow a horn, so it would sound more "naturally" like an IC engine powered car (speaking as a bicyclist, not much is more annoying than a car behind blowing its horn. Yes, we KNOW there are cars behind us who may pass at any time). Such a device would also detect external noise generated by other traffic and increase the volume of the generated sound enough to be heard over it. (Have I thought of all the objections?)

Reliable computer detection of pedestrians and bicyclists is problematic, but the DARPA challenge has demonstrated that such object detection (and even avoidance, if programmed in) is possible. In short, We Have The Technology.