For months, Google has been testing its self-driving car to properly steer, brake, turn, and change lanes like a proper driver – but in the latest report, it has learned the number one rule of road rage: Honking.

According to the report, the team taught the car’s artificial intelligence to honk as a way to give other drivers on the road a heads up, such as toward a car driving down the wrong way of a one-way street or backing out of a blind driveway.

When it first learned to honk, each time the car decided to sound the horn, it first played only inside the vehicle so the researcher sitting inside could mark whether the honk was appropriately used. Then, the team allowed the car to honk at its own discretion.

The car also uses two types of honking sounds: two short beeps for a heads-up type alert, or a loud, sustained honk for emergency situations. Google did not report having to use the emergency honk so far.

So the next time you come across a Google autonomous car and hear a horn, it’s definitely not because it found your “Honk if you’re horny” bumper sticker amusing.

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