CARS that can drive themselves, a staple of science-fiction, have started to appear on roads in real life. Google’s self-driving vehicles are the best-known, but most carmakers are also developing them. In 2011 BMW sent a robotic car at motorway speeds from Munich, the German carmaker’s hometown, to Nuremberg, about 170km away (with a driver on board just in case). Audi got a self-driving TTS Coupe to negotiate 156 tight curves along nearly 20km of paved and dirt road on Colorado’s Pikes Peak, with nobody behind the wheel. Proponents say that driverless cars would reduce road deaths, ease congestion, reduce fuel consumption, improve the mobility of old and disabled people and free up time spent commuting. So how do they work?
