The finalized prototype of Google self-driving car.

(Tech Xplore)—Google has revealed in its latest monthly report on how things are going with its autonomous car testing program, that it has recently been testing the automatic use of the horn by the vehicle. They note that the original reason for adding a horn to a car or truck, was to alert other drivers or pedestrians to its presence, thereby preventing clearly avoidable accidents. Since, that time, using the horn has become a sort of emotional extension to driving by some, but Google promises that adding horn honking to the automated features of its cars, will be strictly designed to follow the original purpose.

Before adding automatic horn honking to its driverless vehicles, Google engineers studied the conditions under which horn honking is appropriate, and determined that instead of a single honk sound, maybe two would be more appropriate. Letting someone know that they are straying from their lane, might really only necessitate a couple of quiet "pips" for example—a gentle, yet polite means of waking someone to what is occurring. On the other hand, if a is about to back into the road just ahead, a loud blare is clearly needed to gain immediate attention and hopefully incite quick action by the other driver.

Google engineers have also noted that many people find horn honking by others to be irritating—especially when it was not really needed. To test autonomous honking, they only played the honks inside their cars for a period of time, with the lone passenger taking notes and reporting back to engineers. The company apparently believes they have the kinks worked out as they have now begun allowing their cars to honk at others when the software deems it necessary.

Honking was not the only noise on the minds of the engineers though, they have also been brain-storming ideas regarding causing its vehicles to emit noise in general, so that others will know that they are there on city streets. Google's cars are electric, and like other electric vehicles, pedestrians sometimes do not see them, because they expect to hear them. Also, blind pedestrians have no other way to detect them. Google has begun experimenting with having their vehicles emit different sounds, such as a hum that simulates gasoline powered cars. But, they are also apparently interested in giving their vehicles a unique sound, one that will soon become associated with Google vehicles—work on that front, they note, is still progressing.

More information: www.google.com/selfdrivingcar/