Autonomous Driving Levels Explained

From driver assistance features to full self-driving, we explore the levels of autonomous driving and what they mean for the future of driving.

There are Levels to This

When is “self-driving” not actually self-driving? Always; at least with today’s technology. Yet you might not know that given how current driver assistance technologies are marketed. Terms like “hands-free,” “Autopilot,” and even “Full Self-Driving” get tossed around without regard to what they actually mean to engineers, regulators, or the driving public. We don’t have self-driving cars. At least not yet.

It turns out, vehicle autonomy has specific, codified levels as outlined by the SAE or Society of Automotive Engineers. These levels cover everything from basic safety equipment like your rearview camera to fully autonomous vehicles whisking us about in some future Blade Runner-esque cityscape.

So why is this important to the non-engineers out there? Because carmakers are enthusiastic about the commercial potential of current driver assistance technologies. Plus, those current technologies are the foundation upon which further levels of autonomy are being built. (If nothing else, the trove of data Tesla is accruing with their Autopilot and Full-Self Driving beta testing helps explain their sky-high stock evaluation.) In other words, car companies are incentivized to fudge the language surrounding autonomous driving technology.

But it’s not just carmakers getting things confused. Just last month, the New York Times published an editorial expounding the virtues of GM’s SuperCruise in their new Cadillac Escalade. In that article, the author repeatedly, though perhaps unintentionally, clouds the line between driver assistance technologies and self-driving.

Given the general opacity surrounding this issue, it’s important for consumers to know what level of driver engagement is required in the vehicle they’re buying (both legally and technologically speaking).

Level 0

Level 0 means no driver assistance technology. The vehicle is controlled solely by a human at the wheel. This covers traditional and new safety technologies like anti-lock brakes, blind spot warning systems, stability control, and lane departure warnings.

Level 1

Adaptive cruise control - hyundaiusa.com

Level 1 is where we enter the realm of driver assistance technologies. Occasionally the car may control either speed (acceleration and/or braking) or steering, but never both at the same time. Drivers still retain full control of the vehicle at all times. Examples of these driver assistance features include things like lane centering/lane-keep assist or adaptive cruise control. These features have become common and even standard on new vehicles.

Level 2

Jumping to level 2 might be one increment on this scale, but it’s a significant leap in technological sophistication. Level 2 indicates vehicles equipped to control both steering and speed in specific circumstances. Often this takes the form of “hands-free” driving technologies where the vehicle can manage tasks like lane centering and even lane changes in relatively simple driving environments such as highway driving. Tesla’s Autopilot and Full-Self Driving, despite the name, fall under level 2, as does GM’s SuperCruise system. Critically, all level 2 systems require an attentive human behind the wheel ready to take full control of the vehicle at a moment’s notice. No napping, no texting, no cooking a bowl of Ramen on a hotplate on your passenger seat.

Level 3

Level 3, while not here yet, appears right around the corner. This level includes systems that will include true “hands-free” driving in some situations like highway driving and in traffic jams. Even level 3 technology will still require a human driver to take over in many complex driving scenarios including heavy urban traffic, construction zones, or those involving inclement weather. It’s yet unclear the exact contours of when such systems will require a hand-off between the vehicle’s driving assistance systems and a human driver. In 2019, Audi said it was ready to deploy a level 3 system in their A8 sedan, but US and European regulations weren’t met, and the project has since been shelved. Still, Tesla, Mercedes, and GM are just a few carmakers on the cusp of deploying some version of level 3 autonomy, pending regulatory approval, of course.

Level 4

By the time we get to level 4 autonomy, we have vehicle systems that no longer require human intervention. Basically, level 4 is where you get to text to your heart’s content, guilt free. Such vehicles may or may not have manual driving controls like a steering wheel or pedals. The most likely path to level 4 is through ridesharing/taxi vehicles and public transportation like buses. Such vehicles would operate under a system of geofencing that restricts them to a pre-programmed route and specific speed limits. As sophisticated as these systems are likely to be, they may still run into trouble with inclement weather.

Level 5

Mercedes autonomous concept car - media.mbusa.com

Fully autonomous driving arrives at level 5, where no human intervention is needed regardless of the scenario or conditions. It’s unclear what this will ultimately look like. For a time, even with level 4, traffic is likely to be a mix of human and autonomously controlled vehicles. A century or more may pass before all vehicles are fully autonomous. Though some experts question whether level 5 is even achievable, let alone desirable.