Audio Pedestrian Warning Sound

[rostym]

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?

 

[alohart]

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.

 

[Mustrum Ridcully]

Is the actual sound made defined or only something like a range of frequencies and how loud it must be at a set distance?

 

[eNate]

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

 

[Mustrum Ridcully]

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.

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.

 

[eNate]

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).

 

[robthebold]

. . . 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.

 

[robthebold]

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.

 

[Mustrum Ridcully]

Still, it is more math than I can handle these days. In just a few years I expect to be back to counting on my fingers and toes if I can't ask Siri.

 

[alohart]

For those who don't want a pedestrian warning system, the 2019 U.S. i3 is the latest model year without it yet it has all other features of later model years, some color choices excepted.

 

[tongsli]

in my 2021, I was able to disable the sound (using bimmercode) except for in reverse, which I liked. That car was totaled and I'm back into another i3, 2019

 

[websterize]

in my 2021, I was able to disable the sound (using bimmercode) except for in reverse, which I liked. That car was totaled and I'm back into another i3, 2019

I assigned activation of the ghost in the machine to one of the programmable macro buttons. Read 'Bmw i3 acoustic pedestrian warning failure'
https://www.mybmwi3.com/threads/bmw-i3-acoustic-pedestrian-warning-failure.18426/post-75222

 

[TheAirman]

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.

 

[robthebold]

in the parking lot, under 25mph, deadly silence.

That's an interesting turn of phrase . . . Yikes . . .