What Does Level 4 Autonomous Driving Mean?

[VonAniyah]

Level 4 autonomous driving refers to high-level autonomous driving that can achieve the entire driving process without any driver intervention, but it also has certain limitations, such as restricting the vehicle speed to a certain limit and operating within relatively fixed driving areas. It generally relies on real-time updated road information data to support functions like automatic vehicle pickup/return, automated platooning, and obstacle avoidance in real-world driving scenarios. In the SAE Levels of Driving Automation published by SAE International (Society of Automotive Engineers), besides Level 4 autonomous driving, there are five other levels. Level 0 is manual driving, where, according to SAE's definition, the driver fully controls all operations including steering, braking, and acceleration. The vehicle only executes commands, so this level is not considered autonomous driving. Level 1 is driver assistance, where the driver still needs to operate the vehicle, but safety systems like ACC (Adaptive Cruise Control) provide assistance. The driver must keep hands on the wheel and eyes on the road. Features such as adaptive cruise control, lane-keeping assist, and automatic braking in luxury brands like Volvo and Mercedes-Benz fall under Level 1 autonomous driving. Level 2 is partial automation, where the vehicle can simultaneously control acceleration/deceleration and steering, meaning adaptive cruise control and lane-keeping systems can work together. Most automakers have already achieved Level 2 autonomous driving technology. Level 3 is conditional automation, where the vehicle can autonomously handle acceleration, deceleration, and steering in specific environments without driver input or monitoring of surroundings. However, the driver must remain attentive and ready to take over if the system encounters unmanageable situations. The Audi A8 is the world's first production car capable of Level 3 autonomous driving on public roads. Level 5 is full automation, requiring no driver intervention under any conditions. It can operate in all weather and geographic conditions, allowing the driver to focus on rest or other tasks. However, legal and technological breakthroughs are still needed before widespread adoption. Autonomous driving demand analysis: The essence of autonomous driving technology is to replace human labor with artificial intelligence in specific scenarios, improving efficiency and reducing labor costs. Its underlying logic is similar to industrial robotics' "machines replacing humans," profoundly impacting industries like transportation, logistics, and commercial services. Thus, labor cost savings directly reflect the economic value of autonomous driving. All vehicles that do not require human operation fall under autonomous driving. Based on scenario openness, speed (divided by 20 km/h), and cargo type, autonomous applications can be categorized into open/closed, high/low-speed, and passenger/cargo dimensions. High-speed open-road autonomous driving is the most challenging and promising, attracting top-tier companies, but commercialization remains distant. In contrast, limited-scenario autonomous applications have lower technical barriers and faster commercialization. Fully manual driving models are rare, with Tesla being one example. The market categorizes driving modes into six levels: L0 (manual), L1 (assisted), L2 (partial automation), L3 (conditional automation), L4 (high automation), and L5 (full automation). Currently, the highest commercially available level is L2, which still requires human oversight for safety.