电动汽车很安静，但也许太安静了

There's an ongoing controversy over whether electric vehicles (EVs) should emit sounds to let the blind and other pedestrians know they're on the scene. Some think those sounds should be standardized — like the "beep, beep, beep" of heavy machinery backing up, so you'll think "something heavy this way comes" when you hear it.

关于电动汽车是否应该发出声音让盲人和其他行人知道他们在现场，一直存在争议。有些人认为这些声音应该标准化——就像重型机械倒车时发出的“哔，哔，哔”的声音，所以当你听到它的时候，你会认为“有重物从这边来了”。

Several car companies have created their own sounds, especially for cars marketed outside the United States.

一些汽车公司已经创造了他们自己的声音，尤其是针对美国以外市场的汽车。

If an electric car goes down the road and no one is around to hear it, does it make a sound? (Photo: Scharfsinn/Shutterstock)

This is a serious subject, though. Plug-in hybrid cars and battery EVs are super-quiet, and a study at the University of California, Riverside concludes that people listening to recordings on headphones can hear a regular gas car coming from 28 feet away, but a hybrid in battery mode only when it's seven feet away.

不过，这是一个严肃的话题。插电式混合动力汽车和电动汽车的电池非常安静，加州大学河滨分校的一项研究得出结论，戴耳机听录音的人可以听到28英尺(约合1.8米)外的普通汽油汽车发出的声音，但只有在7英尺(约合1.8米)外的时候，才能听到电池模式的混合动力汽车发出的声音。

In response, the European Union has put new rules into play: As of July 1, all new electric vehicle models must have a noise-emitting device, which sounds like a traditional engine. Starting in 2021, all new electric vehicles of any model will need the acoustic vehicle alert system or AVAS. That sound will come into play when the car is reversing or when it's traveling at less than 12 miles an hour.

作为回应，欧盟出台了新的规定:从7月1日起，所有新型电动汽车必须配备一个噪音排放装置，听起来像传统发动机。从2021年开始，所有新型电动汽车都将需要声学车辆警报系统(AVAS)。当汽车倒车或以低于每小时12英里的速度行驶时，这种声音就会开始发挥作用。

That's a nice start, say representatives for the blind, but more is needed.

盲人代表说，这是一个良好的开端，但还需要做得更多。

This action followed in the steps of Japan, which was an early adopter, passing its rules in 2010. Meanwhile, the National Highway Traffic Safety Administration passed its final ruling in February 2018, requiring vehicles to emit sound if they're traveling slower than 18.6 mph.

这一行动紧随日本的步伐，日本是最早的采纳者，于2010年通过了相关规定。与此同时，2018年2月，美国国家公路交通安全管理局通过了最终裁决，要求汽车行驶速度低于18.6英里每小时时必须发出声音。

Drivers in most instances have the ability to shut off the device when needed.

在大多数情况下，驱动程序能够在需要时关闭设备。

My guess is that they will eventually be standardized so your mind will automatically register "electric car" when you hear it. And that's probably a good thing to reduce the mayhem on the roads.

我的猜测是，它们最终将被标准化，因此当你听到“电动汽车”时，你的大脑将自动登记。这可能是一件好事，以减少道路上的混乱。