Autonomous driving, or self-driving, involves vehicles equipped with systems capable of performing driving tasks with minimal or no human intervention. The Society of Automotive Engineers (SAE) has classified six levels of driving automation, each with distinct capabilities and limitations.

The Six Levels of Autonomous Driving:

• Level 0 (No Automation): The driver is fully responsible for all aspects of driving at all times. Any support systems, such as lane departure warnings or forward-collision alerts, only provide alerts or brief interventions to help the driver, without taking control of the vehicle.
• Level 1 (Driver Assistance): Under specific conditions, such as on a well-marked highway, the vehicle can assist with either steering or acceleration/deceleration but not both simultaneously. An example is adaptive cruise control, which adjusts speed to maintain a set distance from the car in front. However, the driver must remain actively engaged, hands on the wheel, and eyes on the road.
• Level 2 (Partial Automation): In certain conditions, like highways with clearly defined lanes, the vehicle can control both steering and speed simultaneously. Systems like Tesla’s Autopilot or GM’s Super Cruise are examples, where the vehicle can stay within its lane and maintain speed or following distance. However, the driver must always be ready to take over immediately if needed, as these systems cannot make complex decisions or respond to unpredictable scenarios.
• Level 3 (Conditional Automation): The vehicle can fully control steering, acceleration, and braking in very controlled settings, such as low-speed traffic on highways. Level 3 systems may allow the driver to take their hands off the wheel temporarily. However, the driver must remain alert and ready to intervene upon request, as the vehicle cannot handle unexpected or complex situations (e.g., construction zones or merging traffic) on its own. Honda’s Legend sedan and Audi’s A8 are early examples of Level 3 vehicles, though their availability is limited.
• Level 4 (High Automation): The vehicle can perform all driving functions without human assistance in specific, pre-defined conditions, such as geo-fenced urban areas or certain highways. In these controlled zones, the car can manage complex driving tasks, like navigating intersections and dealing with pedestrians. However, outside these areas, or if weather conditions exceed the vehicle’s limits (e.g., heavy snow or fog), the vehicle may require human intervention or may not operate at all. Waymo’s autonomous taxis operate at Level 4 in selected areas within set geographic and environmental parameters.
• Level 5 (Full Automation): Level 5 represents complete autonomy, with the vehicle able to handle all driving tasks under any conditions, from highways to rural roads, in various weather conditions, without any human input. These vehicles would not need a steering wheel or pedals, as they’re designed to be fully self-sufficient. Level 5 remains the ultimate target for the industry, though it has not yet been achieved and may require further technological breakthroughs and regulatory approvals.

Why Levels and Conditions Matter for Consumers and the Industry

Each level has specific conditions that dictate how, where, and when it can operate autonomously. Levels 0 to 2 are widely available in consumer vehicles, primarily providing driver assistance features for highway driving. Levels 3 and 4 are in the testing and early deployment stages, with Level 4 beginning to see commercial use in limited areas. Level 5, the ideal of true autonomous driving in all conditions, remains a goal for the future.