What is the difference between L2 and L3 autonomous driving?

[VonMalia]

Autonomous driving L2 is semi-autonomous driving, while L3 can achieve partial autonomous driving operations in specific environments. Here are the detailed introductions: 1. L2: L2 achieves semi-autonomous driving, allowing the vehicle to perform multiple functions, and the driver can take short breaks with their hands, but they still need to be ready to take over the driving task at any time. The functions included in L2 level are: full-speed adaptive cruise control, automatic parking, active lane keeping, speed limit recognition, automatic lane changing, etc. 2. L3: L3 enables the vehicle to perform partial autonomous driving operations in specific environments. It can judge whether to continue autonomous driving or return to manual operation by the driver based on road conditions, which can be considered as autonomous driving. The vehicle can almost independently complete all driving operations.

[VanConnor]

As a commuter with years of driving experience, I have a deep understanding of the differences between L2 and L3. L2 is like having adaptive cruise control and lane-keeping assist—the car can steer and adjust speed automatically, but I have to keep my eyes on the road and traffic at all times, with my hands ready to take over the wheel. There’s no room for relaxation. Using it during rush hour on the highway saves some effort, but even a moment of distraction, like glancing at my phone, could lead to an accident. L3 is different. Under specific conditions, such as on highways, the system can fully control the driving, allowing me to occasionally read a book or handle emails. However, if the car alerts me to take over, I must react immediately. Unfortunately, most cars today only support L2 because L3 requires infrastructure and regulatory support, and if the system fails, the responsibility still falls on me. Overall, L2 is practical but limited, while L3 is smarter but carries higher risks. When choosing, it’s essential to check the vehicle specifications carefully.

[LaIker]

From a technical perspective, L2 autonomous driving primarily relies on cameras and radar sensors to assist drivers with steering and acceleration, while requiring continuous human monitoring of the environment to handle unexpected situations. L3, however, represents an upgrade by incorporating lidar and high-precision map algorithms, enabling full control of driving tasks in specific scenarios like highways or urban expressways. Drivers can temporarily disengage but must respond to system prompts. The core distinction lies in the control level: L2 is partial automation with driver responsibility, whereas L3 is conditional automation that reverts to human control only during system failures. Sensor accuracy and data processing capacity remain bottlenecks, with L3 potentially experiencing more failures in rainy conditions and higher maintenance costs. In daily use, L2 features like adaptive cruise control are more prevalent, while L3 testing remains limited due to regulatory restrictions. Future upgrades to L4 will demand even higher reliability.

[StellaFitz]

In terms of safety responsibility, for L2 autonomous driving systems like lane-keeping assist, the driver bears full responsibility in case of an accident because the system is merely an assistant and requires constant supervision. L3 differs in that the system takes over driving on permitted road sections, allowing the driver to relax slightly, but immediate action is required upon takeover prompts. If an accident occurs during system operation, the manufacturer may share liability, though many gray areas exist. In practice, L3 is less common due to uncontrollable risks, and even insurance companies struggle with claim rules. Driving advice: always prioritize safety and don't over-rely on these features.

[MilaFitz]

Current regulatory restrictions significantly impact the distinction between L2 and L3: L2 features like assisted driving are widely approved globally and directly available; L3, however, is only piloted in certain regions such as German highways requiring road condition certification, while China is still reviewing safety and hasn't approved it yet. This stems from the dispute over liability - accidents under L3 may fall on automakers, but delayed responses still rely on humans. When choosing a car, prioritize models with manuals to understand limitations and avoid using L3 in restricted areas. Inconsistent standards slow adoption, making a unified testing framework crucial for the future.