Driving in a city offers up a wealth of sounds and distractions, most notable among them is the roar of a gasoline engine and the irate honking of horns. Google’s self-driving car prototype has neither one of those things: it’s electric, and, so far, mostly silent.
However, the engineers behind the self-driving car know the importance of honking. Alerting surrounding drivers to a threat they may not have noticed before can go a long way to prevent crashes, especially when the car is weirdly silent. In order to teach the self-driving cars proper beeping protocol, they gave them driving lessons in test cities in Mountain View, Calif., Kirkland, Wash., Austin, Texas, and Phoenix, as shown in this progress report picked up by Endgadget.
At first, Google engineers minimized the risk of disturbing other drivers with errating beeping by having the car play the sound softly inside the cabin. After it had learned a little more, they gravitated to an external noise. Test drivers gave manual feedback to engineers about whether the software was behaving correctly.
The “driving lessons” included learning the difference between unusual but predictable behavior and recklessness, “i.e. the difference between a car facing the wrong way during a three-point turn, and one that’s about to drive down the wrong side of the road.”
Google has also experimented with using different kinds of sounds to indicate the severity of the situation: “two short, quieter pips” will get a driver’s attention, while “one loud sustained honk” will indicate severe distress and warn of an imminent collision.
In addition to making a polite but forceful beep, Google is working on creating a distinct sound for the car itself, which, without an internal combustion engine, could be dangerously quiet. They’re still working on a highly-engineered sound that would increase safety and “insert a little personality and create a unique voice for our self-driving car.” So far, they’ve worked on replicating the patterns of internal combustion engines, increasing a humming sound when the car speeds up and quieting again when it slows down.
