Proposed Minimum Sound Requirement Rule for Hybrids and EVs - Please comment

Proposed Minimum Sound Requirement Rule for Hybrids and EVs - Please comment

Here are is the article published by the NHTSA about their rule proposal for noisemakers on Hybrids and EV's. The proposal was sent for publication in the Federal Register yesterday. After publication in the Federal Register there is a 60 day public comment period. You will find a link to the proposal at the bottom of the article. Instructions for submitting comments are in the document.

I would encourage thoughtful comments on this proposal. Personally, I think that the requirements are excessive and I am not convinced that it will have any impact at all on their safety goals. I think that constant noisemaking at speeds of 18 mph and below will just add to the problem by increasing ambient noise and confusion making it even more difficult to identify moving Hybrids and EV's.

I think that they can do much better.

dborn | 11 januari 2013

While I wouldn't want noise either, is it technically possible to " focus" noise so that it is projected in a very restricted ( collimated) cone and not audible within the vehicle? This can be done with x rays, so why not sound? That way it achieves the stated object, does not contribute to general noise pollution, and keeps the vehicle as is, quiet.

Timo | 11 januari 2013

...unless you happen to be on the path of the sound beam.

LRAD does just what you are talking about.

Problem with sound is that once it hits anything it deflects and scatters and in city environment where that would be needed most and where sound pollution as problem is worst you quite fast end up in situation where sound would be coming from all directions anyway.

Captain_Kong | 11 januari 2013

Ringtone of an ice cream van, no less

BYT | 11 januari 2013

"Ringtone of an ice cream van, no less"

Don't want that, disappointed kids will pelt your car with eggs.

wonder | 11 januari 2013

Emit Led Zeppelin or maybe Italian Opera :-)?

wonder | 11 januari 2013

Maybe the sound of a baseball card on a bicycle wheel anyone :-).

Sudre_ | 11 januari 2013

I was walking thru an underground parking garage today and I heard the sound of just tires on pavement approaching me slowly. I turned hoping it saw a Model S but it was a Prius. No engine noise, it was traveling about 5-10 mph, and I had no problem hearing it from behind me.
Good thing I wasn't blind or I'd probably be dead. (Mel, for your information the last bit there was sarcastic and meant to be humor.)

jgreenhall | 11 januari 2013

We don't need more noise. We need more quiet electric cars.

Captain_Zap | 1 maart 2013

I'm bumping this topic because we are getting close to the close of the comment period.

Please act!

GeekEV | 1 maart 2013

I don't know about most people, but I tend to drive around with the stereo bumpin' - so you'd hear me coming anyway...

Superliner | 1 maart 2013

No, and No! Our State and Federal Government have MUCH bigger fish to fry than worrying how much noise my BEV makes or does not make. I can already make noise if I want to ... it's called a HORN! and has worked for all kinds of vehicles for over a hundred years.

stimeygee | 1 maart 2013

Anecdotally, a guy I work with was just run over (ankle broken) by a Prius running in electric mode which he did not hear. Yes, he was jaywalking, and no he doesn't blame the Prius. But if it had been an ICE he probably would have heard it. Just sayin.

Captain_Zap | 1 maart 2013


Let it be known here:!submitComment;D=NHTSA-2011-0148-0049

Thoughtful comments at this site are our only hope at this point and the 60 day comment period is nearly gone.

Superliner | 1 maart 2013

@ stimyg

That's the Fault of the Driver of the Prius. You cannot run into things that appear in your windshield view, especially pedestrians who ALWAYS have the right of way!

It's unfortunate as you say but you can't fix stupid with any noise.
Pedestrians still get hit by trains! And it's not like you can't hear them coming! or expect them to swerve to miss you!

Captain_Zap | 1 maart 2013

+1 Superliner


Probably need to add a maximum volume for personal entertainment systems while walking rule to the bill. Or how about a minimum number of times a pedestrian is required to look around per minute rule.

jbunn | 1 maart 2013

Question, Nick. What noise should my car make to prevent me from running into parked cars? Or is it the responsibility of the driver to not hit parked cars, pedestrians, trees, ect?

Second question, once every car starts making all manner of noises, how do we hearing impaired people sort out the real important stuff from noise. Fyi, for some of us hearing impared, its not soud, but noise, that prevents us from hearing properly.

Pungoteague_Dave | 1 maart 2013

I noticed something interesting about silence when driving the car. We have several thousand deer on our farm. Our driveway is about a mile long. We encounter deer nearly every night on both the nearby road and our driveway. In all of our ICE vehicles, the deer look up and then scatter. In the Model S, the deer NEVER even flinch. They just keep munching away, and we drive on, with no disturbance. Sometimes I have to beep the horn to get them out of the way. Onthe one hand, I have a new hunting technique. On the other, we are concerned that one day a deer will jump out on a larger road when we are at speed.

I have hit two deer on my motorcycle inthe past three years, one bad enough to put me in the hospital for a few days with a brain bleed. I like that the Model S is nearly silent. However, this may be a legitimate issue - people and animals use all kinds of visual and auditory indicators for self-preservation, and not having the auditory signals may count for more than we want to think.

I don;t like the idea of a government-imposed sound mandate, but this may be a necessary change for our cars, especially in urban areas where the blind depend on sound for mobility.

DouglasR | 1 maart 2013

Whether it's a good idea or not, the regulation will not affect our cars. It is proposed to have a slow phase-in, and it will not be retroactive to cars produced before it takes effect.

cloroxbb | 1 maart 2013


Since when do pedestrians always have the right of way when not in a crosswalk? Jaywalking is ticketable for a reason, just barely enforced in most places.

Of course if the Prius had time to AVOID the pedestrian, or stop, then its definitely on the Prius, but if not, then its the pedestrians fault. But that doesnt give the pedestrian a right to cross a street whenever and wherever they like.

Captain_Zap | 1 maart 2013

Time is of the essence. Comments should be directed to the NHTSA.

The NHTSA public comment period for rulemaking for noise makers on hybrids and EVs close in a couple days. This is the last chance that I know of for anyone to have any say in the rule before it is written in indelible ink.

This is a summary of the rule from the news release:

"The sounds would need to be detectable under a wide range of street noises and other ambient background sounds when the vehicle is traveling under 18 miles per hour. At 18 miles per hour and above, vehicles make sufficient noise to allow pedestrians and bicyclists to detect them without added sound. Each automaker would have a significant range of choices about the sounds it chooses for its vehicles, but the characteristics of those sounds would need to meet certain minimum requirements. In addition, each vehicle of the same make and model would need to emit the same sound or set of sounds."

The news release about the rule is here:

The place to make comments is here:!submitComment;D=NHTSA-2011-0148-0049

Superliner | 1 maart 2013

@ cloroxbb

IMHO, Pedestrians have the right of way wherever you encounter them (including when they are where they should not be) Don't think so? Try hitting and injuring a few and see what happens.

That said "by letter of the law" Yes a pedestrian CAN be at fault in a car / ped. wreck. but that's a law I personally don't want to test or even flirt with. So "TO ME" the right of way will always belong to the people who are afoot.

cloroxbb | 1 maart 2013

Meh, we are only arguing semantics. I wouldn't say they have the "right of way" but of course, I am not going to hit one just because they are in the wrong. I understand where you are coming from, and I agree. I just wouldnt say they have the right of way.

Same page :)

Brian H | 1 maart 2013

Geek EV;
One of those, huh? Let me get my resolver ...

jbunn | 1 maart 2013


Here on the Left Coast, pedestrians ALLWAYS have the right of way. Streets, parking lots, crosswalks, whatever.

I understand on the East Coast they are legitimate targets, but not here. You get used to it. I say that as both a driver and a pedesterian.

skymaster | 1 maart 2013

The Chevrolet Volt has a "pedestrian horn" on the tip of the turn signal. It works fantastic.

Captain_Zap | 2 maart 2013


c.bussert67 | 2 maart 2013

I feel like BYT...
This annoys me. How about they mandate eye contact. I see you, you see me. Its as much the drivers responsibility as the pedestrians. If I walk or ride my bike, I've got my head on a swivel looking for clueless drivers. When I drive, I look for dummies on the wrong side of the road buzzing down the street.
The fact it applies to EVs? Has anybody 'heard' a new Jag?
Blood pressure rising...
Rage taking over...
Must exit now!

Captain_Zap | 2 maart 2013

Don't exit! Please go comment at the site.

The place to make comments is here:!submitComment;D=NHTSA-2011-0148-0049

My ICE was just as quiet as my Model S too.

c.bussert67 | 2 maart 2013

Aye, cap'n!
I will comment. I just feel these are uphill battles. But fight while you can. Might stave it off for now. Going against groups of politicians that get paid to do these laws. They just push and reword until they get what they want. Saying what I said earlier about silent ICE, doesn't mean I want it applied to them. I think it should be dropped as a whole. But I doubt it will. Like a virus, it'll be back as a different form. But I will fight. >:-/

Mark E | 2 maart 2013

Most modern vehicles are too quiet to hear anyway. It'd be interesting to see if there are any statistics out that show hybrids as being involved in any more accidents than regular ICE machines. My guess is that there wouldn't be, and if the study were done it would be negligible.

Brian H | 2 maart 2013

Mark E;
Exactly. I bet there's no data supporting this. Nor even visually impaired association support (they tend to want less auditory "clutter", and this will increase it!)

Pbfoot | 3 maart 2013

This proposed rule almost certainly came about as a result of a push from the visually impaired. My friend is national manager for safety for a major car company. Last year he and his other safety engineer peers from other companies were all invited to a meeting with a national organization for blind people, at which time they were presented with information regarding the blind people's concern for silent vehicles and the risk for blind pedestrians due to inability to hear oncoming hybrids and EVs. So it is not surprising to hear that this has become a mandate from NHTSA.

cerjor | 3 maart 2013

What is being done for the deaf? The sound won't help them. It would be interesting to see statistics about injuries to the deaf vs injuries to the blind.

Pungoteague_Dave | 3 maart 2013

This is being supported financially and legislatively by the National Federation of the Blind. Many studies have shown that EV and hybrid cars create increased danger to pedestrians with impaired vision. Perhaps we shouldn't have our head in the sand on this issue:

From Wikipedia:

"Research conducted at the University of California, Riverside in 2008 found that hybrid cars are so quiet when operating in electric mode (EV mode) that they may pose a risk to the blind, small children, the elderly, runners, cyclists, and other pedestrians, as they may have only one or two seconds, depending on the context, to audibly detect the location of approaching hybrid cars when the vehicles operate at very slow speeds. This research project was funded by the National Federation of the Blind.

The experiment consisted of making audio recordings of a Toyota Prius and combustion engine Honda Accord approaching from two directions at 5 miles per hour (8.0 km/h) to assure that the hybrid car operated only with its electric motor. Then test subjects in a laboratory listened to the recordings and indicated when they could hear from which direction the cars approached. Subjects could locate the hum of the internal combustion engine car at 36 feet (11 m) away, but could not identify the hybrid running in electric mode until it came within 11 feet (3.4 m), leaving just less than two seconds to react before the vehicle reached their position. In a second trial, the background sounds of two quietly idling combustion engine cars were added to the recordings to simulate the noise of a parking lot. Under this condition, the hybrid needed to be 74 percent closer than the conventional car before the subjects could hear from which direction the cars approached. Subjects could correctly judge the approach of the combustion car when it was about 28 feet (8.5 m) feet away. This result means that under closer to normal environmental noise, a pedestrian would not be able to correctly determine the hybrid's approach until it was one second away."

"After Nissan's new sounds were publicized, the U.S. National Federation of the Blind issued a statement saying that "while it was pleased that the alert existed, it was unhappy that the driver was able to turn it off."[13] The NFB approves the Nissan Leaf's forward motion sound, but it said the forward noise should also be used for reversing because the "intermittent sound is not as effective as a continuous sound" and that the car should emit warning sounds when it is idling, not only when it's moving slowly. Nevertheless, their main complaint is that they don’t think the driver should be able to switch the sound off."

nickjhowe | 3 maart 2013

@P_D - I'd love to see them do the same test with an executive sedan, Rolls Royce, Bentley, etc. My guess is that a <10 mph they are as quiet as an EV. I posted this on the NHTSA thread.

If this regulation gets passed, then any car that falls below a certain dB level needs to be subject to the rule, not just EVs and hybrids.

penguin_brian | 3 maart 2013

Link to Wikipedia article?

Sudre_ | 3 maart 2013

Pungoteague_Dave already blew his argument when he mentioned how the deer did not scatter at the lack of sound from his Model S yet he has hit two deer on a motorcycle.... because we all know how quiet motorcycles are.

I can see now that once the cars start making noise the drivers will have an excuse after they run someone over, "Well my car makes a pedestrian warning sound."

Pungoteague_Dave | 3 maart 2013


Just because I hit two deer on the quietest ICE motorcycle BMW K1600GTL) does not mean that the quiet car issue isn't there with respect to deer. As I described, the deer don't flinch or seem to recognize this car, even when I am within feet - we drive right on buy with no reaction. On all of our other vehicles, including a Prius, tractors, trucks, etc., they look up when we are hundreds of feet away, and then scatter when we are about a hundred feet from them.

The problem with deer is that when they do move, they are unpredicatble. The issue isn't quiet vs noisy. They move BECAUSE of the noise, but often when it is too late to react. MOST of the time, they move out of danger. Some of the time, they move directly into the hit zone. That's what happened to me, both times at highway speeds on interstates - I saw the deer, but when they reacted, it was directly into my path. With the Model S, I can drive right up to them and they don't move at all. I happen to own land with several thousand deer, so experience this all the time, but only when I am driving at driveway speeds of 15 or so, so can stop before hitting them. It will be interesting to see how many peoiple hit imobile deer with these cars - because of LACK of sound.

I am NOT advocating for sound makers on the Model S, just pointing out some facts that we should be alert to.

Pungoteague_Dave | 3 maart 2013

The same Wiki piece did refer to other quiet ICE cars beginning to have the same issue, and that the blind activists are asking for noisemakers there too.

There is argument on both sides, my point is that contrary to some other posts here, this is being pushed and funded by the National Federation of the Blind, and there have been many studies from several angles.

More commentary form the wiki piece:

"A separate 2008 study from Western Michigan University found that hybrids and conventional vehicles are equally safe when travelling more than about 20 miles per hour (32 km/h), because tire and wind noise generate most of the audible cues at those speeds. Hybrid cars were also tested safe when leaving a stoplight and it was found that under this condition they do not pose a risk to pedestrians. All Prius models used in the study engaged their internal combustion engines when accelerating from a standstill and produced enough noise to be detected.[9]

A 2009 study conducted by the U.S. National Highway Traffic Safety Administration found that crashes involving pedestrians and bicyclists have higher incidence rates for hybrid electric vehicles than internal combustion engine (ICE) vehicles in certain vehicle maneuvers. These accidents commonly occurred in zones with low speed limits, during daytime and in clear weather. The study found that a HEV was two times more likely to be involved in a pedestrian crash than was a conventional ICE vehicle when a vehicle is slowing or stopping, backing up, or entering or leaving a parking space. Vehicle maneuvers were grouped in one category considering those maneuvers that might have occurred at very low speeds where the difference between the sound levels produced by the hybrid versus ICE vehicle is the greatest. Also the study found that the incidence rate of pedestrian crashes in scenarios when vehicles make a turn was significantly higher for HEVs when compared to ICE vehicles. Similarly, The NHTSA study also concluded that the incidence rate of bicyclist crashes involving HEVs for the same kind of maneuvers was significantly higher when compared to conventional vehicles."

I don't normally view wiki as a good source for anything, but this seems factual. link here:

penguin_brian | 3 maart 2013

So my question is:

Is the higher incidence rates for hybrid electric vehicles due to pedestrians expecting to hear a car approaching and as such don't "see" it approaching?

Or is it that hearing takes priority over sight in certain situations?

If the first case is true, as people become more and more aware of silent vehicles (bikes, quiet ICE, and BEV) they will start paying more attention.

I think there is a lot of research too that proves under certain circumstances, if you don't expect to see something, you wont see it, even if you stare straight at it. e.g. This is a significant safety issue in Australia for motorbikes and bikes; drivers, etc, don't expect to see them and as a result don't see them even if they look.

Here is the video that illustrates this point. Make sure you are paying attention before watching it.

Some documentation (watch the video first before looking at this):

Superliner | 3 maart 2013

And once everything out there is blaring away with alert noises their effectiveness will be diminished. Anyone remember driving before "High Mount Stop/Brake Lights" became a requirement? Once they were required they got everyone's attention for awhile because no one was used to seeing them so for a time the bright red lamp directly in your forward line of sight was effective. But how about now? When is the last time you remember even noticing one? or making a distinction between a high mount or any other brake lights?

A non sighted individual is little different than a seeing individual blasting his/her headsets while walking and looking the other way as it pertains to oncoming traffic.

All accidents cannot be legislated away or every possible eventuality prepared for. Nor can stupid be fixed. As in most cases, no "new" laws or requirements seem in order here. Just "enforcement" of existing laws and for "us" as EV drivers to realize what our choice of transportation beings into the mix in the wild.

@ penguin_brian;

Great Videos,
The gorilla video has been used in awareness training for some time. I remember seeing it "or similar" back in the 80's and could not believe how I could have missed it. Classic not seeing the tree for the forest!

Mark E | 4 maart 2013

I can vouch for the fact that even with a noisy ICE vehicle, people walk in front. I drive a V8 with a rumbling exhaust. It doesn't stop pedestrians from walking in front without looking - especially at low speed.

Adding noisemakers to EVs won't help, and will just cause noise pollution.

Pungoteague_Dave | 4 maart 2013

The same arguments were used against seat belts (I will be trapped, I am not stupid enough to hit anything), air bags, crumple zones, rollover standards, side impact standards, elevator announcements, talking crosswalks, helmet use, etc. l won't call naysayers Luddites, but the solution on the Volt appears pretty reasonable and many Volt owners think it is effective. It puts the onus for pedestrian warning on the driver, so as to not automatically pollute with sound, but does it with a sound that is less noxious than a standard horn. If we go in saying "no" like the environmentalists did on Keystone, we will be seen as the crazy fringe that are represented in some of this thread's alarmist responses, and will be steamrolled just like the pipeline naysayers are about to be. It might be better to manage this process than to end up under the bus entirely.

Pungoteague_Dave | 4 maart 2013

The Volt's pedestrian alert system is demonstrated here:

Seems reasonable.

Brian H | 4 maart 2013

Yes, but is irrelevant to a mandate for a continuous warning tone, which is the subject of the legislation. Every EV, noise-making, all the time.

Captain_Zap | 4 maart 2013

Very true. Brian H

EV's and Hybrids are everywhere around here. There can be a dozen or more in an intersection or garage moving at low speed at the same time.

As more EV's and Hybrids hit the road the constant noise will be more of a hazard than help.

Captain_Zap | 4 maart 2013
TeslaRocks | 5 maart 2013

If you're going so slow that you don't make a sound, it doesn't look like the setup for a very violent accident now does it? Seems to me that some people are looking for any way possible to lower the appeal of electric cars and hopefully (to them) delay their supremacy.

Brian H | 24 september 2014

Buy a cowbell, lower your window and shake it. Use little or a lot of force, depending on need. |:-p