The Six Levels of Autonomous Driving Technology

Table of Contents

Self-driving cars were once a mere dream portrayed in science fiction. Today, they are becoming increasingly realistic, with automakers working tirelessly to bring fully autonomous vehicles to life. 

While many manufacturers claim their cars are ready to drive themselves, legal and regulatory restrictions currently prevent this technology from being fully utilized. 

To standardize the understanding of autonomous driving capabilities, the Society of Automotive Engineers (SAE), a renowned American engineering group, has outlined six levels of driving automation. 

These levels detail the progression of automation technology in vehicles, from no automation to full autonomy.

The Six Levels of Autonomous Driving Technology

Understanding these six levels helps to determine how advanced your vehicle is and what lies ahead for the automotive industry. Let’s explore each level.

Level 0 – No Driving Automation

At the foundational Level 0, there is no automation whatsoever. The driver is entirely responsible for controlling the car, regardless of whether it operates using a manual or automatic gearbox. 

While vehicles at this level may include features to assist the driver, such as cruise control or warning systems for lane departure or blind spots, these functions require manual activation and are not considered automated. 

Even automatic emergency braking systems fall under Level 0, as they only kick in momentarily and do not represent continuous automated operation.

Level 1 – Driver Assistance

Level 1 begins the journey toward automation, introducing at least one feature that aids the driver in steering, braking, or acceleration under limited circumstances. 

Examples include adaptive cruise control, which adjusts speed to maintain a safe distance from other cars, or lane-keeping assistance systems that help prevent the vehicle from drifting out of its lane. 

Parking assistance is another common Level 1 feature, where the car can reverse park on its own. While these systems enhance driver convenience, they require the driver to remain actively engaged with the vehicle’s operation.

Level 2 – Partial Driver Assistance

Level 2 takes automation a step further with advanced driver assistance systems (ADAS) that combine multiple Level 1 functions. With ADAS, the car can steer, accelerate, and brake autonomously in certain approved conditions, such as specific road areas or weather zones. 

However, the driver must remain attentive and ready to intervene if necessary. For this reason, Level 2 driving is often described as “hands-off” rather than fully autonomous. 

While current technology has made these systems prevalent in modern vehicles, they remain a support function rather than a comprehensive self-driving solution.

Level 3 – Conditional Driving Automation

At Level 3, cars are capable of fully autonomous operation in specific conditions and areas. Here, the human occupant technically becomes a passenger rather than a driver. 

The vehicle manages steering, braking, and acceleration entirely on its own, allowing the occupant to remove their hands from the wheel and eyes from the road. However, this hands-free driving isn’t without limitations. 

The car requires the passenger to remain alert and ready to take control upon request, making activities like sleeping off-limits.

Although Level 3 technology demands advanced sensors and AI, regulatory restrictions mean that most countries do not yet permit Level 3 systems on public roads. A notable exception lies in Japan, where Honda launched a Level 3-capable vehicle under strict regulations.

Level 4 – High Driving Automation

Level 4 represents a significant leap forward in autonomous driving capabilities. Vehicles at this level are capable of fully self-driving operation in most scenarios, making it possible for passengers to take a nap or otherwise disengage during trips. 

However, this level is geographically limited to predefined zones known as "geo-fenced areas," which come equipped with highly detailed maps and optimal weather conditions. Speed limitations may also apply in these areas to ensure safety.

While passengers can regain manual control of the vehicle under Level 4, this action is entirely optional and only permitted when deemed safe. 

The introduction of Level 4 technology is expected to lead to new urban solutions, such as driverless “robotaxis” designed for ridesharing services. 

Furthermore, as shared autonomous vehicles become widespread, car ownership may decrease significantly, resulting in transformative changes for transportation systems worldwide.

Level 5 – Full Driving Automation

Level 5 marks the pinnacle of driving automation: vehicles that are capable of independent operation in all driving conditions. 

Unlike Level 4 vehicles, which are geographically constrained, Level 5 vehicles can drive anywhere, including off-road terrain in the case of applicable vehicle types. 

This level is expected to redefine automotive design—it eliminates the need for traditional controls like steering wheels and pedals, as the car no longer requires human intervention at any stage of the journey.

Current Development and Challenges

While advancements in driving automation continue rapidly, global regulations and public safety standards present barriers to widespread adoption. 

SAE has recently updated its definitions, distinguishing Levels 0 through 2 as “driver support systems” and Levels 3 through 5 as "automated driving systems.” 

This clarification emphasizes the increasing shift of legal responsibility: at Levels 0 to 2, the human driver remains fully accountable, while Levels 3 to 5 place the majority of decision-making on the vehicle.

Technological progress varies between manufacturers and regions. Many modern vehicles already feature Level 2 systems, offered by companies such as Tesla, General Motors, Volvo, and Mercedes. 

Level 3 automation, however, sparks debates about safety and liability. Some automakers, like Ford, are bypassing Level 3 entirely due to concerns about overlap between human and machine control, shifting their focus to Level 4 systems instead.

Tesla remains a prominent name in autonomous driving due to its “AutoPilot” program, which is classified as Level 2. Its much-anticipated “Full Self-Driving” upgrade, currently in beta testing, will eventually classify as Level 3 once launched for public use.

The Road Ahead

Autonomous vehicles are steadily becoming a reality, with production-ready technologies multiplying each year. 

Although challenges remain regarding regulatory approvals, safety, and technological hurdles, it’s clear the automotive industry is heading toward a future where self-driving cars will transform transportation. 

From enhancing convenience and safety to reshaping car ownership, the potential of autonomous driving systems is vast.

With companies like Tesla, Honda, and others continuing to push boundaries, the dream of self-driving cars is no longer science fiction—it’s only a matter of time before fully autonomous vehicles become the norm.