TOKYO: Toyota unveiled its vision for self-driving cars in a challenge to other automakers as well as industry newcomer Google Inc., promising to start selling such vehicles in Japan by 2020. Toyota Motor Corp. demonstrated on a regular Tokyo freeway Tuesday what it called the 'mobility teammate concept,' meaning the driver and the artificial intelligence in a sensor-packed car work together as a team. In the demonstration, a Lexus drove itself within the 60 kpm (37 mph) speed limit for about 10 minutes, changing lanes, braking and steering. The human at the wheel did nothing except turn on a button to kick in the technology.