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Discussion Starter #1
Was reading something posted by MotorTrend and it says that by 2019, all new hybrid and electric vehicles are going to be required to make some sort of sounds alerting pedestrians that they are there.

US regulators say it'll prevent 2,400 injuries annually

The noise apparently doesn't have to be constant though. If the vehicle is under 10,000lbs, it must make audible noises when moving up to 19mph. After that wind noise, tire noise, etc, should be loud enough according to the NHTSA

What kind of noise are they going to be making ? I'm expecting something out of the Jetsons..


To comply with this final rule, hybrid and electric vehicles will
instead have to meet a requirement specifying either two or four one-third octave
bands. Vehicles complying with the four-band requirement must meet minimum
sound pressure levels in any four non-adjacent one-third octave bands between
315 Hz and 5000 Hz, including the one-third octave bands between 630 Hz and
1600 Hz (these bands were excluded in the NPRM). Vehicles complying with the
two-band requirement must meet minimum sound pressure levels in two non-
adjacent one-third octave bands between 315 Hz and 3150 Hz. For the two-band
requirement, one band must be below 1000 Hz and the second band must be at or
above 1000 Hz, and the two bands used to meet the two-band requirement also
must meet a minimum band sum requirement.

The NPRM proposed that the fundamental frequency of the sound emitted by a
hybrid or electric vehicle must vary as the vehicle changes speed by one percent
per km/h for speeds between 0 and 30 km/h to allow pedestrians to detect vehicle
acceleration and deceleration. This requirement was referred to as “pitch
shifting,” and it is not required in the final rule. Instead, the final rule assists
pedestrians in detecting increases in vehicle speed by requiring vehicle-emitted
sound to increase in sound pressure level by a specified amount as the vehicle’s
speed increases. The agency acknowledges that the concept of increasing sound
pressure level with increased speed is not a direct replacement for pitch shifting,
but we believe it is a reasonable alternative that will provide useful audible
information to pedestrians about the operating state of nearby vehicles.
 

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I would be surprised if the rule was limited to EV's as there are quite a few combustion vehicles that are very quiet.
 

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What kind of noise are they going to be making ? I'm expecting something out of the Jetsons..
Full document can be found here:
https://redirect.viglink.com/?format=go&jsonp=vglnk_147916325479911&key=5571228bb04e008b467a126d6af6bf81&libId=ivinh3d901011kx5000DAb44pk17b&loc=https%3A%2F%2Fwww.cnet.com%2Froadshow%2Fnews%2Fits-the-law-electric-cars-must-make-noise-after-september-2019%2F&v=1&out=http%3A%2F%2Fwww.nhtsa.gov%2Fstaticfiles%2Frulemaking%2Fpdf%2FQuietCar_FinalRule_11142016.pdf&ref=https%3A%2F%2Fmail.google.com%2Fmail%2Fu%2F0%2F&title=It%27s%20the%20law%3A%20Electric%20cars%20must%20make%20noise%20after%20September%202019%20-%20Roadshow&txt=the%20full%20rule%20(PDF)%20right%20here.
As to the sound:
To comply with this final rule, hybrid and electric vehicles will
instead have to meet a requirement specifying either two or four one-third octave
bands. Vehicles complying with the four-band requirement must meet minimum
sound pressure levels in any four non-adjacent one-third octave bands between
315 Hz and 5000 Hz, including the one-third octave bands between 630 Hz and
1600 Hz (these bands were excluded in the NPRM). Vehicles complying with the
two-band requirement must meet minimum sound pressure levels in two non-
adjacent one-third octave bands between 315 Hz and 3150 Hz. For the two-band
requirement, one band must be below 1000 Hz and the second band must be at or
above 1000 Hz, and the two bands used to meet the two-band requirement also
must meet a minimum band sum requirement.

The NPRM proposed that the fundamental frequency of the sound emitted by a
hybrid or electric vehicle must vary as the vehicle changes speed by one percent
per km/h for speeds between 0 and 30 km/h to allow pedestrians to detect vehicle
acceleration and deceleration. This requirement was referred to as “pitch
shifting,” and it is not required in the final rule. Instead, the final rule assists
pedestrians in detecting increases in vehicle speed by requiring vehicle-emitted
sound to increase in sound pressure level by a specified amount as the vehicle’s
speed increases. The agency acknowledges that the concept of increasing sound
pressure level with increased speed is not a direct replacement for pitch shifting,
but we believe it is a reasonable alternative that will provide useful audible
information to pedestrians about the operating state of nearby vehicles.
 

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Toyota system, as weird as it sounds in person and through video, is effective and I like it, much better than most of the Camry hybrid Taxi's i've come across which some people might not hear. If you have headphones on or are just on the phone it's possible you might not pick up on it.

 

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Not surprising. From the Spark EV's manual

Your vehicle is equipped with an automatic sound generation and a manual alert.

The automatic sound is generated to indicate the vehicle presence to pedestrians. The sound changes if the vehicle is speeding up or
slowing down. It is activated when the vehicle is shifted into a forward gear or R (Reverse), and up to 30 km/h (19 mph).


I don't know if it meets the proposed standard but it's not really obnoxious.
 

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I would be surprised if the rule was limited to EV's as there are quite a few combustion vehicles that are very quiet.
How about a new law with a very high fine for all vehicle that make too much noise, including motorcycles? BTW, one of the benefits of EV and hybrids is the little (fans and audio systems only) or no noise while stationary.

Now imagine all those same cars with their crazy noisemakers coming on as they accelerate from a traffic stop!!:(
 

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My Leaf has a pedestrian warning sound effect. It sounds like you are hearing the car's electric motor whir, even though that is actually inaudible. Very discreet.
 

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Discussion Starter #9
Toyota system, as weird as it sounds in person and through video, is effective and I like it, much better than most of the Camry hybrid Taxi's i've come across which some people might not hear. If you have headphones on or are just on the phone it's possible you might not pick up on it.

http://www.youtube.com/watch?v=63AaD8vYTag
Hit the nail on the head when you said weird... But this definitely gives me an idea of what it sounds like. Kinda reminded me of a horror movie sound effect at the beginning but then I just started thinking of the great unknown (space)
 

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That sounds so weird on the Prius C, I can just see myself getting irritated when I'm slowly cruising around a parking lot.
 

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That's a sound I can get behind! The Bolt already has a shark fin antenna, just need to paint it in grey and you're all set.
 
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