Google self-drive test car Driverless taxis could soon be a common sight on our streets after two private car-hailing apps, Lyft and Uber, both recently announced plans to test them on US roads “within a year”. 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. And once driverless vehicles are common on our roads, no one needs to own one. They could be left anywhere and serve as taxis for everybody to use.
Inside a Mercedes-Benz driverless car
How LIDAR works
Lidar, radar and GPS
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 (left), 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.
An advanced Global Positioning System (GPS) tracks the course of the car and plots a route to its destination. This is a much more accurate version of today’s satnav systems, capable of measuring, for example, the height of the kerbs, the position of the traffic lights and the exact width of the lane the car is travelling in. The system combines GPS data and driving speed to determine the precise position of each vehicle, accurate to within a few centimetres, while making constant corrections for traffic congestion, road construction and accidents.
An accident scene
Robot vs Human
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