The little blue light used for intelligent driving, rumored to be banned outright, has actually been legitimised? In July, the authorities instructed car manufacturers to stop using the blue light in new models. But the story didn't end there. On October 20, the MIIT solicited public comments on five mandatory national standards. In the revised proposal, the blue light was not outright banned but granted a new identity: L3 and above autonomous vehicles need to be equipped with a sign light to indicate to other road users that the autonomous system is active. The sign light should be blue-green. Let's discuss why the blue light was banned, and why it was given a new identity, and most importantly, why the threshold is set at L3. One: Why did it go from a hit to a nationwide ban? First, a cold fact: The blue light was not invented by Chinese car manufacturers. In 2015, Mercedes-Benz debuted a future mobility concept car at CES, lighting up the first autonomous indicator light with blue LEDs. In 2019, SAE in the United States issued a recommended practice suggesting cyan-blue to indicate automated driving status. Key point: It's a recommendation, not a mandate. What really turned it into a signature cue was the Li Auto L9, which in 2022 put a blue light strip on its exterior mirrors. The script then became familiar: BYD, NIO, XPeng, AITO, Xiaomi, and over a dozen other manufacturers followed suit, from 100k-range family cars all the way up to million-dollar SUVs. According to data from Zoss Automotive Research, by the first half of 2025, the blue light assembly quantity in Chinese passenger vehicles reached 755,000 units, with an assembly rate of 7.1%, up 1,098% year-over-year. Why did this light become popular? Two reasons, one elegant, one not. The elegant one is safety: Whether the autonomous system is on or off, it's invisible to the outside world. Turning an invisible ADAS state into a visible light signal creates a new interaction channel between the car and the driver, reducing the risk of traffic accidents caused by information asymmetry, logically sound. The less elegant one is cut-throat competition. The electric vehicle market has already become homogeneous, and autonomous driving has become the only differentiator for car manufacturers. A single blue light, with its bright visual memory, is the lowest-cost "high-end" feature. But this light wasn't compliant from the start. Current national standards stipulate that only four colors—white, yellow, amber, and red—are allowed for external lights in civilian vehicles, and the "blue" color is exclusively for special vehicles like police cars and rescue vehicles. China Automotive Standardization Research Institute also pointed out the safety risks: The blue light could lead to light misuse, causing glare and discomfort for other drivers at night, leading to misjudgment of road conditions, and making it easier for vehicles with blue lights to be cut in front of or closely followed, increasing safety risks. Thus, on July 29, the authorities officially notified: New models should not use the blue light. Two: Eliminating pseudo-innovations in the industry. Why does the blue light have to be at L3? Because the gap between L2 and L3 is not just about the technical level, but also four words: Liability Subject. In the L2 stage, regardless of how capable the system is, the driver remains the subject of responsibility. But in L3, once an accident occurs during the system's activation period, the liability subject shifts to the manufacturer. Thus, the new regulation allocates the indicator light to L3, essentially aligning the responsibility and the signal light. This light more resembles a public announcement: The car is now being driven by the system, and any accidents will be the manufacturer's responsibility. What about old owners who have already spent money on the blue light? For older cars that cannot be upgraded to L3, automakers will most likely disable it via OTA, and the assisted-driving blue light will gradually disappear. New models need to meet most of the requirements of the "External Lighting and Optical Signal Requirements for Cars and Trailers" standard within seven months of its implementation. Vehicles that have already obtained type approval will start implementing the standard after 37 months of its implementation. The restrictions go beyond ADS marker lights at L2 and below. The draft also stipulates that apart from illuminated emblems, no lamp may use a translucent surface or projection to display any text, and lit patterns may not form faces, animal faces or any other anthropomorphic graphics. Additionally, the use of gestures or voice to turn off the light is not allowed, and if a lamp is switched on by voice, the vehicle must indicate where the manual switch is. Why is this so? A real incident happened recently: A car owner on a dark highway said to the voice system, "Turn off all reading lights," and the system interpreted it as "Turn off all lights," and all the lights went out! Deepal Auto Chairman Deng Chenghao posted a statement that day in support, saying, "Prohibiting lights to display text, prohibiting pure voice and gesture controls, fundamentally aims to eliminate pseudo-innovations and quick-fix fads in the industry. Cars are a matter of life and safety. Real intelligence means getting basic safety right, rather than chasing flashy gimmicks." Three: L3 regulations are being rapidly filled. One light turning official is the result of a whole set of regulatory frameworks needed for L3 autonomous driving to be implemented, which are being rapidly filled. Let's count the timeline: In August, the MIIT released the mandatory national standard "Safety Requirements for Combined Driving Assistance Systems in Intelligent Connected Vehicles" for implementation in January 2027. The United Nations also recently approved the global technical regulations for autonomous vehicles, which were jointly led by China, the EU, the UK, the US, Canada, and Japan. Based on the UN regulations, China has formulated its own mandatory standard "Safety Requirements for Autonomous Driving Systems in Intelligent Connected Vehicles," scheduled for implementation in July 2027. On August 28, the NPC released the draft amendment to the Road Traffic Safety Law, adding a chapter on autonomous vehicles, clarifying the legal requirements for autonomous vehicles on the road. The three pieces of the puzzle—technical standards, product access, and road rights—are being placed one by one. At the World Intelligent Connected Vehicle Conference on October 21, companies like BYD, XPeng, and Momenta all agreed that L3 autonomous driving will enter the commercialization phase in 2028. Looking back at the rise and fall of the blue light, it's almost a microcosm of China's intelligent automotive industry: From a rapid, uncontrolled expansion, it's moving towards a more refined and legalistic approach. Should the blue light only be on at L3? (By Autohome Peng Fei).