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Self-drive cars

Google self-drive test carGoogle self-drive test car US tech giants, such as Google and Apple, along with traditional carmakers such as BMW and Volvo, are racing to build the first self-drive car. The cars will use existing technologies, such as lidar radar and GPS, to enable them to sense their surroundings in fine detail and navigate without human control. The number of road accidents—most of which are caused by human error—may one day fall dramatically as a result. There are two kinds of self-drive cars: autonomous cars, which take over from the driver for only part of the time, and full driverless cars, in which the vehicle does all the driving. Once driverless vehicles became common on our roads, no one would need to own one. They could be left anywhere and serve as taxis for everybody to use.

Inside a Mercedes-Benz driverless carInside a Mercedes-Benz driverless car

How LIDAR worksHow LIDAR works


Light Detection and Ranging (or lidar) technology is used to build a constantly changing 3D map around the car. It allows the car to “see” any potential hazards ahead by bouncing a laser beam off objects surrounding it in order to calculate exactly their distance and shape. Lidar is already commonly used by geologists, seismologists and other researchers to make high-resolution maps. Because lidar cannot accurately monitor the speed of surrounding vehicles, radar sensors also send signals to the car’s computer to apply the brakes, or move out of the way, whenever other vehicles come close.

In this animation showing how lidar works, a beam (coloured red) from a laser range finder is reflected by a rotating mirror. The laser scans the object (the green disc), gathering distance measurements, which are represented by blue crosses in the lower diagram.


Worldwide 1.2 million people are killed each year road accidents. In the US alone, 33,000 people are killed—the equivalent of an airliner crashing five days a week.

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