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Comment by fire_lake | Hacker News Reader

Big improvements, but keep in mind that air and tyre resistance are the loudest aspects of driving at even moderate speeds.

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This. People always underestimate how much noise rolling resistance of tyres plays in the sound profile of traffic. Electric cars are worse under 50mph, basically because they're heavier.

An ICE engine is vastly louder stationary at a stoplight or stuck in heavy traffic. Both of which are is really common in cities.

Regenerative braking is also vastly quieter.

Electric cars start and accelerate noiselessly - both very common activities in the inner city driving.

The parent's point is that the engine isn't the largest contributor of noise. At low speeds the engine noise dominates, at "high" (meaning normal driving speeds) speeds the tire noise dominates.

Go listen to a highway and see if you can hear the engines over the wooshing.

A bit of an aside on this. The last 30 years or so have been amazing for cutting down engine noise levels. In trying to squeeze out ever last drop of efficiency they have also reduced the noise levels.

Nowadays the only times I really notice them is either when idling or something from before the 90's is driving past.

This is the point that makes all of the miserable noise pollution from modified cars so much more grating, knowing that whatever is making excess noise means potentially useful (in a performance sense) power is escaping as sound somewhere in their drivetrain, so insofar as their objective is to make their vehicles loud for the sake of loud, these people are achieving the opposite of what they're trying to signal they're achieving.

Efficiency and power are not equivalent. All you need to do is look at the most powerful (hp per liter) cars and the exhaust systems they use for proof.

The people were talking about are slapping shitty cat deleted straight pipe exhausts on what are typically engineered to be economy or family cars, or small displacement motorcycle engines. People who don't see the offensively selfish stupidity in tripling or quadrupling the noise output of their mode of transportation just to get an extra 10% power, if that.

They're not running million dollar F1 cars around closed environments dedicated to the purpose.

The other day I noticed a queue of suspiciously quiet gas cars. One or two had start-stop systems.

(Hybrids of course all implement start-stop, and after 20 years of wild success are still underrated)

On residential vehicles. Commercial vehicles are still a nuisance.

Cars in cities rarely travel quickly, spending lot’s of time stopped at traffic lights right where people cross the street or stuck in traffic.

The squeal of a worn out brake pads is largely mitigated by regenerative breaks which increase brake lifespan.

There are a lot of highways in American inner cities.

Those are frequently Highways in name only. If people are doing 2-3 mph in stop and go traffic it might as well have stop lights. Thus the frequent use of bypasses so people on long trips can actually get someplace quickly even if the distance increases.

Interstate 5 in Seattle would like a word with you. The traffic noise on that road is paradoxically loudest when nobody is driving on it.

It’s 8PM on a Sunday, and it currently has some traffic issues.

The only paradox is it seems louder when the rest of the city quiets down.

Another reason to limit inner city traffic to 30 km/h to 40 km/h :)

> Go listen to a highway and see if you can hear the engines over the wooshing.

I regularly walk a trail ~0.5mi from a highway and the main sound I notice is from straight piped WRX-esque cars gunning it.

I don’t think this is something that occurs to people. When I jog, i noticed pre-AirPods pro that I could listen to podcasts fine on the side street blocks that i normally run on, but once I hit the avenue (more traffic and 30-40 speed), it’s hard for me to hear without noise cancellation.

In Europe at least, where most (?) transmissions are still manual, you will still get way more noise from an ICE vehicle than an electric vehicle at low speed. This is my experience everywhere here in cities, on small roads, etc. This is largely caused by the fact that people tend to not drive in an optimal manner (i.e. using a low gear instead of a higher one).

No they are not. Electric cars are notably quieter under 50 mph. They are notably quieter at all speeds really.

Over 30km/h road noise dominates and EVs generate similar noise to ice cars: https://www.toi.no/getfile.php/1340825/mmarkiv/Forside%20201...

And that pollution of tire degradation is one of the biggest sources of particles from cars

Don’t forget the brakes. When the rotors get worn down, where did they go?

Not a big issue with evs, most use regenerative breaking.

As do hybrids! Even mild hybrids like those new pickups

The rotors aren't the problem, the pads are. Rotors are just cast iron, and they wear very slowly compared to the pads.

Do you have a source for that claim? Typically I see breakdowns by chemical formula

For example,

https://www.theguardian.com/environment/2022/jun/03/car-tyre...

https://www.washingtonpost.com/climate-environment/2023/07/0...

In residential and downtown areas, the sound is going to be dominated by engine idling, pulling away, and low speed cruising. It's ridiculous to argue that electric motors aren't a massive improvement in all of these cases.

Yup,Electric cars aren't quieter at all compared to movement I.C.E cars. Speeds need to be lowered to 35km/hr or lower.

Maybe inside of a regular electric car, but the worst noise pollution in cities comes from cars and motorcycles with modified exhaust and incessant honking. Cars are loud and that's a problem by itself, but a car with a bad driver is exponentially worse than one with a normal driver.

That’s one part, but the other massive part is noise from freeways and the baseline white noise from faster roads, where most of the noise comes from tires. EVs are not better (and typically worse since they’re heavier) — the only way to fix it is 1. No freeways in city centers. 2. Fewer cars. 3. Noise barriers. 4. Asphalt that reduces tire noise (uncommon in North American cities, where concrete is used to improve the lifespan).

I can’t use my balcony in a downtown city center because the baseline tire noise from the highway is so loud, and that’s without the obnoxious exhaust

Must really depend on the speed, because the experience I have with ICE vs electric at Europe city speeds, electric vehicles seem practically silent.

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