Visitors view a sand table about a smart system to improve public transportation network during the World Transport Convention held at China National Convention Center in Beijing, capital of China, June 14, 2019. Themed "Green and Intelligent Mobility for Future Transport", the event showcases the latest achievements in transport technologies. (Xinhua/Shen Bohan)

Visitors view a road disease inspection robot during the World Transport Convention held at China National Convention Center in Beijing, capital of China, June 14, 2019. Themed "Green and Intelligent Mobility for Future Transport", the event showcased the latest achievements in transport technologies. (Xinhua/Shen Bohan)

A visitor tries a system that can test a driver's ability to identify hazardous traffic situations during the World Transport Convention held at China National Convention Center in Beijing, capital of China, June 14, 2019. Themed "Green and Intelligent Mobility for Future Transport", the event showcased the latest achievements in transport technologies. (Xinhua/Shen Bohan)