China’s traffic light industry has evolved rapidly over the past century, shifting from fully imported basic equipment to a self-developed, high-quality manufacturing sector. The first traffic signal was installed in Shanghai in 1923, with limited use in major cities until the 1980s. Post reform and opening-up, the industry standardized domestic production, and LED technology replaced traditional incandescent lights by the 2000s. Since the 2010s, smart, networked traffic lights have dominated, powered by big data and intelligent control, covering hundreds of thousands of intersections nationwide with near-full LED penetration.