Washington: The US patent for self-driving cars has been awarded to internet search giant Google.
The intellectual rights relate to a method to switch a vehicle from a human-controlled mode into the state where it takes charge of the wheel. It explains how the car would know when to take control, where it is located and which direction to drive in.
The search firm suggests the technology could be used to offer tours of tourist locations or to send faulty models to repair shops.
The application for Transitioning a Mixed-mode Vehicle to Autonomous Mode was applied for in May, but had been hidden from public view until this week.
The document describes using two sets of sensors. The first identifies a "landing strip" when the vehicle stops. This then triggers the second set which receives data informing the machine where it is positioned and where it should go.
Google says the landing strip could simply be a mark on the ground, a sign on a wall, or lines or arrows showing where the vehicle should be parked.
To detect which landing strip it has been parked at, the document says the car could activate a GPS (global positioning system) receiver to find its rough location and then use its sensors to detect trees, foliage or other known landmarks to determine its exact position.
Although the technology described may sound fanciful, Google has been testing a fleet of driverless cars for several years.
The vehicles combine artificial intelligence with the firm`s Google Street View maps as well as video cameras and a range of sensors.
Experts say Google`s "passion project" could end up creating a valuable revenue stream
They add that driverless cars could become a commercial prospect sooner than most people believe.