My old driving instructor always told me that a horn is for warning, not for retribution. Humans may use it for all kinds of reasons—to tell someone you've arrived to pick them up; to inform the driver in front that the light has turned green; to harass someone who is driving the speed limit when you yourself would prefer they drive faster. In its variety of uses, the horn is probably the most expressive part of your car.
But until now, driverless cars have never raised their voices. That's changing, because Google is teaching its autonomous cars to honk.
"The human act of honking may be (performance) art," says Google's self-driving car project May monthly report, "but our self-driving cars aim to be polite, considerate, and only honk when it makes driving safer for everyone."
Because Google's cars are constantly aware of their surroundings, in 360 non-retributive degrees, they notice things humans might not and can administer a sharp honk as a warning.
"Our self-driving software is designed to recognize when honking may help alert other drivers to our presence—for example, when a driver begins swerving into our lane or backing out of a blind driveway," says the report.
To begin, the honks only sounded inside the car, so Google's test passengers could decide whether they were appropriate and hone the car's horn-blowing algorithm.
Deciding when to sound the horn isn't the whole of it either. A human can use the horn for more than just warning, in part because we can be quite expressive with it. A sharp jab on the horn issues could tell another driver that their light is broken, or it could say "Thanks," for letting you pass. A long blare usually indicates that the horn-honker is pissed off or panicked, and two short pips can mean a jolly goodbye as you drive away. Google's algorithms will take a while to match that.
Google has also been tweaking the sounds its cars make, which is a worrying harbinger of future clamor. People often cite silence as a problem with electric cars—you can't hear them coming. But this is only because we're used to jumping out of the way for an impatient driver. In cities, the cars are the intruders. If you want to drive in a dense area, full of soft people going about their lives, then you should have to creep slowly through them, not rely on your vehicle's noise to plough the pedestrians aside. Silence isn't a bug of electric cars, it's a feature, and the only reason we accept car noise is because we're so accustomed to it.
Nonetheless, Google has added gas engine noises to its electric cars. "Our prototype mimics the sound characteristics of traditional cars, such as increasing the pitch when it accelerates, and decreasing the pitch when it decelerates," says the report. But we all know that car makers won't stop at that, and Google has already succumbed: "But we also wanted to insert a little personality and create a unique voice for our self-driving car," it says.
There will surely be a Nissan whistle, a Honda hum, and a Dodge growl in future electric cars, and maybe—like early ringtones—annoying, self-selected sounds for your car. Imagine, if you will, the sound of the future: It's the Crazy Frog, blaring out of the fake grill of an electric BMW, forever.
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