Hacker News new | ask | show | jobs
by bmitc 993 days ago
> the noise from cars is mostly friction and turbulence

Agreed. I can't even hear the engine in my car on the highway over tire and wind noise.

2 comments

People on the outside can hear it though.
I don't think they can unless the car is not moving. The point is: the dominating sound pollution from a car is from sources that are not removed in EVs.
> not moving

You mean like at a stop light or even a stop sign? A very common thing to be near in a city?

You mean when other cars are still moving?

And what is your point, in general? Engines make noise. That's not under dispute.

Unless you're on the far corner, you're only living by one side of the road. Hearing ICE engines rev up to accelerate from a light is a non-trivial amount of noise.
EV “engines” don’t. Way to miss the point.
And the overall point has been that is literally in the noise.
EVs are significantly less noisy on residential streets though. You know, where people live.
Only below 18mph or 30kph.

> As required by the PSEA, (1) this rule proposes to establish FMVSS No.141, Minimum Sound Requirements for Hybrid and Electric Vehicles, which would require [quiet vehicles] to produce sounds meeting the requirements of this standard. This proposed standard applies to EVs and to those HVs that are capable of propulsion in any forward or reverse gear without the vehicle's ICE operating. The PSEA requires NHTSA to establish performance requirements for an alert sound that is recognizable as motor vehicle in operation that allows blind and other pedestrians to reasonably detect a nearby EV or HV operating below the crossover speed. The crossover speed is the speed at which tire noise, wind noise, and other factors eliminate the need for a separate alert sound.

>[...]

> This standard will ensure that blind, visually-impaired, and other pedestrians are able to detect and recognize nearby hybrid and electric vehicles by requiring that hybrid and electric vehicles emit sound that pedestrians will be able to hear in a range of ambient environments and contain acoustic signal content that pedestrians will recognize as being emitted from a vehicle. The proposed standard establishes minimum sound requirements for hybrid and electric vehicles when operating under 30 kilometers per hour (km/h) (18 mph), when the vehicle's starting system is activated but the vehicle is stationary, and when the vehicle is operating in reverse.

https://www.regulations.gov/document/NHTSA-2011-0148-0075

In residential areas 30 is the usual speed limit where I live.
So the 405 will finally be whisper quiet.