The car horn has long been a tool for drivers to express themselves and their frustrations – far exceeding its intended use to alert others of your presence when driving.

Now, Google has revealed it is teaching its self-driving cars how to use the horn, but only with the aim of becoming “polite and considerate and only honk when it makes driving safer for everyone”.

Google car
(Eric Risberg/AP)

In its latest monthly report on the testing of driverless cars in the US, Google revealed that its latest new feature is to introduce a car horn to the computer powering the entire system.

“Our self-driving software is designed to recognise 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,” the report said.

Google car
(Tony Avelar/AP)

“During testing, we taught our vehicles to distinguish between potentially tricky situations and false positives, 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 added that the horn software has been in testing for some time, but initially the sound was only played inside the car in order for test drivers to note whether or not the car was using it appropriately. Having improved the algorithm behind it sufficiently, Google says the horn is now being broadcast fully.