Google’s latest report on its self-driving vehicle project focuses on a feature that could easily be overlooked: the car’s sounds. Engineers are now teaching Google’s autonomous cars how to honk effectively, yet politely. At first, they tested the car’s honking intelligence by keeping the noise inside the vehicle in order to avoid confusing other drivers. Now that the technology has been finalized, honks can be heard on the road while Google’s cars log an average of 10,000 to 15,000 autonomous miles per week.
During the testing period, cars learned not to honk for “false positives” such as a car that appears to be going in the wrong direction but is actually backing up for a three-point-turn. They learned how to properly respond to different situations—two quiet honks provide a friendly head’s up in certain scenarios, while a loud, long honk will be used for urgent and potentially dangerous situations.
In addition to honking, Google’s cars are now equipped to make another sound: a hum that imitates the familiar sound of traditional cars. Since the self-driving cars are electric, they are nearly silent, which isn’t always ideal. A humming sound has been added so that pedestrians, cyclists, and people who are visually impaired will be warned of an approaching car. It mimics the sounds of traditional vehicles—increasing pitch when accelerating, and decreasing pitch when decelerating. But in true Google style, engineers also wanted to add a unique personality to the car’s “voice,” so to find the right sound they tested everything from consumer electronics to ambient art sculptures and even experimented with Orca whale songs.
