What’s different about this autonomous test drive is that it took place not in a prototype but in a model that began selling in Japan last year. It’s a huge bet not just for its manufacturer but for the island nation’s car industry. Nissan and other Japanese automakers have a goal to bring semiautonomous vehicles to city roads by 2020, the same year the Summer Olympics will take place in Tokyo.If Japan’s auto industry misses that opportunity to show off its self-driving prowess, it could fall further behind. Once a colossus that threatened America’s image as the world’s primary industrial superpower, Japan now finds itself flat-footed in the race to develop driverless vehicles. As agile code development has supplanted lean manufacturing as the key ingredient for future cars, Silicon Valley holds a clear advantage.