China's autonomous car market has tripled in size since 2015, and it's expected to top 10 billion yuan this year. Meanwhile, Shenzhen is allowing autonomous vehicles on the road from today, but there are conditions. While the driver's seat can be vacant, somebody must still be present in the vehicle. Regulations are in place to help other drivers on the road, as well as pedestrians who may be walking nearby. For instance, the autonomous vehicles must have on a special light to indicate they're in "self-driving" mode.