Hacker News Reader

Comment by oatmeal1 | Hacker News Reader

Generally agreed, but the noise from cars is mostly friction and turbulence (and honking/sirens). Switching to electric won't solve that.

View on HN

The car noise problem is partially solved (or improved) by EVs, actually. The tires used on EVs tend to be efficient (low rolling resistance), which translates to less noisy tires. Additionally, their body shape tends to aim towards very aerodynamic so they have less turbulence noise. If they didn't do this, their efficiency would be much worse so it essentially becomes a necessity.

It's pretty evident when you drive next to a large vehicle with knobby tires meant for off-roading (Jeeps seem to commonly have these). The tire noise is easily MUCH louder, even ignoring any engine noise.

The other thing, broadly, is road construction can lead to a huge difference in noise from highways. I'm sure you've experienced huge differences depending on the road surface.

I think it is marginally reduced, definitely not solved. It also depends on the tires a consumer puts on their EV once it leaves the factory, and anything about 50kmph is still very noisy.

I think that is good in one aspect though, road noise is the only warning you get that an EV is approaching, which in a PED/Cylcing friendly city is important.

EVs already need to make noise at 19mph or under in the US.

Personally, I'd prefer strongly if road noise were eliminated entirely. It'd lead to a better society broadly by reducing noise pollution. Ped/cyclist safety is better handled by other policies than "just make more noise" IMO.

Well I agree with both points, especially the latter. But I would certainly prefer we solve for the latter first.

I was in Shenzhen recently, walking around the shopping districts, and I was constantly feeling a sense of unusualness. Eventually I figured out that it was because that despite all these cars and scooters on the road, I felt like I was waking in a forest, as most of the sounds I hear are from people, and the cars and scooters are pretty much silent, since so many of them are electric.

> The tires used on EVs tend to be efficient (low rolling resistance), which translates to less noisy tires.

EVs are just cars, any tire that you can put on an EV you can also put on an ICE car, so that is not a differentiator.

EVs tend to be heavier though, and weight is a primary factor in how fast a tire wears.

You can hear the difference with your own ears. Even if a freeway sounds the same, it's obviously different when an EV rolls through the alley or shared driveway vs an ICE car.

Not to mention the jerks intentionally making noise with loud engine mods but I guess there's no getting rid of them.

> 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.

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.

I would think having a vehicle be entirely electric must allow more options in terms of car body shape and even tyre shape/material that could possible reduce noise (and particulate) pollution even further. And certainly if we could reduce the vehicle weight (I gather the current generation of EVs typically weigh 25%+ more than their ICE equivalents - and cars have generally been getting heavier over the last couple of decades anyway, which is a trend that we desperately need to reverse, and won't happen without legislation). Having said that, as a cyclist the idea of not being able to hear cars around me is somewhat disconcerting.

I have no trouble hearing EVs approaching, they sound identical to modern ICE, which is to say 90% road noise.

Some ICE cars are noisier by choice of course but modern commuter cars are very quiet at the exhaust typically, the road noise is the dominant noise.

I have cars driving past me at about 50kph right now, I am barely hearing the engine for about 3 seconds or less as it passes, and the road noise continues to be audible for about 20-30 seconds. Pretty much all I am hearing is road noise. Same was true when I lived near a highway. Just a whooshing blob of road noise.

Driving both a gasoline car and an EV, I can surely tell you that pedestrians get out of the way when I approach with the former much more often than with the latter. So they are no identical. Of course where I live there's no law-mandated minimum noise level for EVs.

We might end up in the weeds here, but I imagine you are meaning when moving relatively slowly? I hope pedestrians aren't in need of moving out of the way of your driving over 25kmph!

Indeed at slow speeds EVs are quieter. That probably does make a difference for inner city traffic, which is also where you really want less tailpipe emissions, EVs help there too.

Reply on news.ycombinator.com