Audio Pedestrian Warning Sound

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rostym

Member
Joined
Oct 20, 2018
Messages
8
I recently sold my 2017 i3 REX and replaced it with a 2021 i3s BEV and could not be happier with the 2021 other than the Pedestrian Warning noise that it makes. I read that BMW added this because it became law in some countries. I've also read that it is no the law in the US. So, can a BMW dealer silence the sounds legally and is it ok with BMWNA?
 
The U.S. Pedestrian Safety Enhancement Act of 2010 set in motion the requirement that all EV's emit a pedestrian warning sound below 30 km/h (18.6 mph). The rules were finalized in February, 2018. Disabling the pedestrian warning system on 2020 and later model EV's would be illegal, so no BMW dealer would do so.
 
The precise sound is not defined but frequencies, decibels, and speeds are. Dig in to FMVSS 141, S6.7.3 "Minimum Sound Requirements for Electric Vehicles."

There was an industry push to allow custom sounds but the the original rule was maintained to limit sounds by model. The NPRM write-up specifically mentions the rule does not apply to individuals (owners who modify the sounds on their own), but that state laws probably prevent this by requiring owners to maintain their vehicles to original specifications.

https://www.federalregister.gov/doc...requirements-for-hybrid-and-electric-vehicles
 
First, Thank you, eNATE, for digging up this multi-page/screen full of regulations. Then, do all BMW 'i' cars have the same sound, or is that sound used on all plug-in electric cars from BMW made after that date? Do they have to change that sound for cars sold in different countries?

I am just wondering if the US has adopted the same rule as everyone else in the 'developed' world. I expect many small independent countries to just rubber stamp the EU or US regulations and call it good. Somehow, I doubt that the USA and the EU have exactly the same requirements. But perhaps sanity was found, and they got together at a "CONFERENCE," that is to say, an expense junket where they all drank too much.

I started reading this document, and if I had continued, I would have had some problems when I attempted to solve this first-year calculus problem: I last used Calculus when I was a student at university 60-odd years ago, and thankfully, I have not had to use it since.
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FMVSS 141, S6.7.3 "Minimum Sound Requirements for Electric Vehicles
Here is less than a 10% extract from this mind-numbing document

§ 571.141 Standard No. 141; Minimum Sound Requirements for Hybrid and Electric Vehicles.​

S1. Scope. This standard establishes performance requirements for pedestrian alert sounds for motor vehicles.
S2. Purpose. The purpose of this standard is to reduce the number of injuries that result from electric and hybrid vehicle crashes with pedestrians by providing a sound level and sound characteristics necessary for these vehicles to be detected and recognized by pedestrians.
S3. Application. This standard applies to—
(a) Electric vehicles with a gross vehicle weight rating (GVWR) of 4,536 Kg or less that are passenger cars, multipurpose passenger vehicles, trucks, or buses;
(b) Hybrid vehicles with a gross vehicle weight rating (GVWR) of 4,536 Kg or less that are passenger cars, multi-purpose passenger vehicles, trucks, or buses; and
(c) Electric vehicles and hybrid vehicles that are low speed vehicles.
S4. Definitions. Band or one-third octave band means one of thirteen one-third octave bands having nominal center frequencies ranging from 315 to 5000Hz. These are Bands 25 through 37 as defined in Table A1, Mid-band Frequencies for One-Third-Octave-Band and Octave-Band Filters in the Audio Range, of ANSI S1.11–2004: “Specification for Octave-Band and Fractional-Octave-Band Analog and Digital Filters” (incorporated by reference, see § 571.5).
Band sum means the combination of Sound Pressure Levels (SPLs) from selected bands that produce an SPL representing the sound in all of these bands. Band sum is calculated with the following equation:

where SPLi is the sound pressure level in each selected band.
Electric vehicle means a motor vehicle with an electric motor as its sole means of propulsion.
Front plane of the vehicle means a vertical plane tangent to the leading edge of the vehicle during forward operation.
Hybrid vehicle means a motor vehicle which has more than one means of propulsion for which the vehicle's propulsion system can propel the vehicle in the normal travel mode in at least one forward drive gear or reverse without the internal combustion engine operating.
Rear plane means a vertical plane tangent to the leading edge of the rear of the vehicle during operation in reverse.
Trim level is defined to mean a subset of vehicles within the same model designation with the same body type and which are alike in their general level of standard equipment, such as a “base” trim level of a vehicle model. Vehicles with only minor trim differences that are unlikely to affect vehicle-emitted sound are not considered different for the purposes of this safety standard.
 
I can't offer any help with interpretation, just to point out that the sound is defined but not strictly defined. I found the Q&A more interesting because auto makers really really wanted their customizable fart sounds (actually Toyota wanted to differentiate their more expensive trim levels).
 
. . . state laws probably prevent this by requiring owners to maintain their vehicles to original specifications.
No vehicle inspections in Kansas, so if I ever get a newer EV, it's gonna get the Six Million Dollar Man "Death Probe" sound for maximum pedestrian safety.
 
There's no calculus there, just taking the two Sound Pressure levels (SPL(1) and SPL(2) -- defined elsewhere, I guess), converting decibels (dB, or one tenth of a bel) to bels, then converting the bels to linear values, summing those values, converting the sum back into logarithmic bels and finally scaling back to decibels. Or more basically: adding up the two signal SPLs.
 
Damn the Fed's and their noise laws. On the i3, I coded it out.

On my Genesis, you just pull the VESS fuse, and wonderful, in the parking lot, under 25mph, deadly silence.

Strangely, on the Genesis, you can through the menu, turn on a sound that is only heard on the interior by the driver or passengers, of either a gas engine, or an electric motor, or a futuristic space ship noise. That off too.

I guess some people just have to noise in their cars.
 
After consulting with this site's administrator, and in keeping with this site's Terms of Service, I have deleted the post describing a method to bypass the pedestrian acoustic warning.

The applicable portion of the TOS reads:

"You agree to not use the Service to submit or link to any Content which is defamatory, abusive, hateful, threatening, spam or spam-like, likely to offend, contains adult or objectionable content, contains personal information of others, risks copyright infringement, encourages unlawful activity, or otherwise violates any laws. You are entirely responsible for the content of, and any harm resulting from, that Content or your conduct.​
"We may remove or modify any Content submitted at any time, with or without cause, with or without notice. Requests for Content to be removed or modified will be undertaken only at our discretion. We may terminate your access to all or any part of the Service at any time, with or without cause, with or without notice."​

As with another recent thread discussing this topic, and I have no intention of closing this one, nor silencing the discussion of this topic. This deleted post wasn't as black-and-white as the former, but due to the "new member" status of the member who posted it, I deleted it. The site will not host this content and will not provide links to these instructions.
 
And here I am wanting to go the other way with it. (But I do have an Adafruit soundboard I am working to integrate in an external speaker system.)
I'm thinking the standard high/low tuba notes, often used to accompany your favorite cartoon character of girth, would be about right.
 
As with another recent thread discussing this topic, and I have no intention of closing this one, nor silencing the discussion of this topic. This deleted post wasn't as black-and-white as the former, but due to the "new member" status of the member who posted it, I deleted it. The site will not host this content and will not provide links to these instructions.
Nuance is important.

It's all in how people use it, as to my understanding NHTSA equipment requirements after sale are up to states to regulate. So while mandated for OEMs on new production, I can't find a state law regulating them (but assume nothing without searching for that yourself).

My external mirror deletion is the same kind of thing. Oregon does not require them to be there if other means of adequate rear view are present, like camera monitors, despite federal law requiring them at the time of original sale.

'Ooom-pah' sounds may be on the near horizon for my car regardless. :LOL:
 
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