Sound of a hybrid car

I recently saw a news report about the noise level of hybrid cars. Apparently, because the cars are so quiet, it's difficult for pedestrians to hear them approaching, which makes them dangerous.

My dad knows about that news too. In fact, he recently had an experience where he didn't notice a hybrid car approaching until it was quite close. I thought to myself, it could definitely be dangerous.

The news said they also tested a sound-making device that emits a sound when a car approaches a person.

It seems they're considering emitting sounds to alert pedestrians. People use their five senses to understand their surroundings, but especially when it comes to things they're not in contact with, they rely on visual and auditory information. However, visual information can only perceive what's within their field of vision, so when something moving, like a car, is approaching from behind, auditory information is necessary to confirm safety. If the sound of an approaching car, like a hybrid, is quiet, then emitting a sound to alert people is a natural idea in a way.

Well, since there aren't many hybrid cars yet, maybe it's okay to have cars that make noise, but when hybrids and electric cars become more common, it feels kind of strange to deliberately make noise. After all, lower noise levels and quieter cars are generally a good thing...

That might be true, Otono. I think they'll probably start implementing technical measures to keep the environment quiet while also ensuring safety.

They also said that quiet cars are a problem for visually impaired people, so it's not just cases where cars approach from behind.

That's right. Have you ever heard of universal design?

Universal design? Does that mean barrier-free?

Yes, they are sometimes used interchangeably, but the following explanation is probably the clearest way to understand the difference. First, barrier-free design is when the target, problem, and purpose are clear from the start, for example, eliminating steps for wheelchair users. But what if the target of the design is a sidewalk, and the target users are visually impaired? Conversely, they might be afraid to walk if there are no steps. Universal design is about developing and designing with as many diverse people as possible in mind. [Reference 1]

Does adding a "noticeable sound" to hybrid and electric vehicles require a universal design perspective?

That's right, ensuring safety for everyone is one of the most important requirements for a car.

In that case, it will become increasingly difficult to reconcile this with efforts to reduce noise levels.

That's where the ingenuity comes in. The sound that alerts you should not be a sound that's inconspicuous, in other words, not noise. Even with home appliances these days, rice cookers make a beeping sound when the rice is cooked, right? Sounds like that that indicate completion or other operational status are called notification sounds, but those notification sounds aren't just random sounds.

A notification sound? Are game sounds also notification sounds?

Most game sounds are sound effects, but even then, when you make a mistake, a short buzzer-like sound plays to let the player know that they didn't perform the correct action. It's important to design notification sounds so that their characteristics (pitch, length, timbre) evoke meaning or nuance. And what's more, they should be pleasant for anyone to hear.

Oh, I see. The sound you hear when you pass through the automatic ticket gates at the station is a short, high-pitched beep when you're allowed to pass, but it makes a ping-pong sound when you're denied entry. Is it a recent development to design notification sounds?

The importance of design has perhaps only been recognized in the last few years. First, automated machines have become commonplace in our cities. Second, things that used to run on machines are now run on electricity. It's a bit of an old analogy, but like how steam locomotives became electric trains, and how gasoline-powered cars became electric vehicles. Machines make sounds that correspond to their mechanical movements, but electricity doesn't. That might be the difficult part. I think sound design will become increasingly important.