A nuTonomy self-driving taxi drives on the road in its public trial in Singapore, Aug. 25, 2016. Developer nuTonomy invited a select group of people to download their app and ride for free in its “robo-taxi” in a western Singapore hi-tech business district. The cars - modified Renault Zoe and Mitsubishi i-MiEV electrics - have a driver in front who is prepared to take back the wheel and a researcher in back who watches the car's computers. (Photo/Agencies)