A driverless car (sometimes called a self-driving car, an automated car or an autonomous vehicle) is a robotic vehicle that is designed to travel between destinations without a human operator. To qualify as fully autonomous, a vehicle must be able to navigate without human intervention to a predetermined destination over roads that have not been adapted for its use.

Companies developing and/or testing driverless cars include Audi, BMW, Ford, Google, General Motors, Volkswagen and Volvo. Google's test involved a fleet of self-driving cars -- six Toyota Prii and an Audi TT -- navigating over 140,000 miles of California streets and highways. A single accident occurred during one of the infrequent occasions when a human was driving. Another test of over 1000 miles was completed successfully with no human intervention. 

Here’s how Google’s cars work:

• The “driver” sets a destination. The car’s software calculates a route and starts the car on its way.
• A rotating, roof-mounted LIDAR (Light Detection and Ranging - a technology similar to radar) sensor monitors a 60-meter range around the car and creates a dynamic 3-D  map of the car’s current environment.
• A sensor on the left rear wheel monitors sideways movement to detect the car’s position relative to the 3-D map.
• Radar systems in the front and rear bumpers calculate distances to obstacles.
• Artificial intelligence (AI) software in the car is connected to all the sensors and has input from Google Street View and video cameras inside the car.
• The AI simulates human perceptual and decision-making processes and controls actions in driver-control systems such as steering and brakes.
• The car’s software consults Google Maps for advance notice of things like landmarks and traffic signs and lights.
• An override function is available to allow a human to take control of the vehicle.

Proponents of systems based on driverless cars say they would eliminate accidents caused by driver error, which is currently the cause of almost all traffic accidents. Furthermore, the greater precision of an automatic system could improve traffic flow, dramatically increase highway capacity and reduce or eliminate traffic jams. Finally, the systems would allow commuters to do other things while traveling, such as working, reading or sleeping.

 

Sebastian Thrun, who helped develop Google’s cars, discusses self-driven cars at TED and shows a demonstration:

The history of driverless cars goes back much further than most people realize -- Leonardo da Vinci designed the first prototype around 1478. Leonardo’s car was designed as a self-propelled robot powered by springs, with programmable steering and the ability to run pre-set courses.

Self-driving vehicles are not yet legal on most roads. In June 2011, Nevada, US became the first jurisdiction in the world to allow driverless cars on public roadways.

 

See also: Global Positioning System (GPS) 

 

Continue reading about driverless cars:

> Wikipedia’s entry about driverless cars

> From Google’s blog: What we’re driving at

> The New York Times reports on Google’s driverless car tests

23 Sep 2011