'It's a long-term journey we're on': taking a ride towards self-driving cars

The journey in a self-driving Nissan across Woolwich in south-east London begins smoothly enough: fitted with cameras and sensors, the electric car confidently handles pedestrian crossings, vans cutting into its lane without warning and even scurrying jaywalkers. Then comes an unexpected obstacle: a football-sized rock, fallen from the back of a lorry on to the middle of the road. The specially trained safety driver hastily grabs the steering wheel, taking back control to avoid a nasty crunch. It is hardly a major incident – and it is the only human intervention during five miles of navigating busy traffic in a demonstration of the ServCity research programme being carried out by the carmaker and partners in London. Nevertheless, it highlights the difficulties facing autonomous driving technology before it can become mainstream – particularly on Britain's busy and often chaotic urban roads.