A quick user-guide to the levels of vehicle automation

We’ve all been told to ready ourselves for the new world of autonomous vehicles rapidly approaching. But what exactly does that mean and what characteristics will the cars of the future have? Perhaps more urgently what semi-autonomous systems are available in vehicles already being sold today and what do they do for us humans? 

In this blog post, we attempt to translate the Society of Automotive Engineers (SAE) Levels of Automation guidelines for the rest of us and give real-world examples as to how you might experience new driver assistance technology (also called ADAS) whether in the next car you buy or when booking an autonomous taxi ride.

Level 0: 

Manual, human driving. No assistance from vehicle.

The driver is in total control of the vehicle. The driver initiates every aspect of the drive including steering, braking, acceleration, and navigation.  

Real-world example: The first 50 years of automobile production.    

Level 1:

Feet off sometimes. Assisted driving

At Level 1, ADAS safety features can assist the driver with some automatic braking, or steering, however, these features are not able to be used at the same time in an automated capacity. The driver still does most of the driving manually, but can engage ADAS (Advanced Driver Assistance Systems) while operating the vehicle. We call this “feet off” and assisted. Feet can come off while cruise control is engaged, for example. Additionally, the vehicle provides some safety assistance, however, the driver must retain full control.  

Real-world example:  Using advanced cruise control during a long highway drive.

Level 2: 

Hands off, sometimes. Partially automated.

Most of today’s semi-autonomous vehicles are considered Level 2. This means that automated steering and automatic braking features can be engaged simultaneously. The driver must still pay attention to the road and be ready for any potential hazards, but in some models, drivers can take their hands off the wheel for a short amount of time while the car steers, brakes and manages speed for them. Importantly, these Level 2 systems do not yet reliably recognize stop signs or traffic lights and most auto manufacturers only recommend using them for highway driving. 

Real world example: You use Tesla Autopilot, GM SuperCruise, Nissan ProPilot, Audi Jam Assistant, Mercedes-Benz Drive Pilot, or Volvo Pilot Assistant to make your daily commute somewhat less stressful. However, if your hands are off the wheel for too long or you otherwise indicate that you are not paying attention, the system will display a warning and turn off.

Level 3: 

Mind off. Highly automated. 

When operating a Level 2 vehicle, the driver must have their hands upon the wheel at least some of the time for the system to continue operating. However, in Level 3 vehicles, the human driver can relax their mind and let the vehicle do even more of the driving. According to NHTSA, the difference between L2 and L3 is that “the vehicle is designed so that the driver is not expected to constantly monitor the roadway while driving.”  It uses the Automated Driving System (ADS), which means the car is highly automated and can perform most driving functions. The Level 3 definition has led to much debate in the industry because, despite the advanced system, most maintain that the human driver still needs to be engaged enough to act if a hazard approaches, or if the semi-autonomous system disengages. 

Real world example: This is the most controversial of the levels because it is the most difficult to pinpoint responsibility and liability if a collision were to occur. At this point in time, we cannot find a single case of a manufacturer currently describing their tech as Level 3. 

Level 4: 

Eyes off. No human intervention in most cases.

The difference between Level 3 and Level 4 automation is in the eyes. The mind can relax in  Level 3, but the driver still has to be somewhat engaged. In Level 4, extremely limited human intervention is required. The driver does not have to pay attention in most situations. The difference between Levels 4 and 5 is the slight possibility of human interference. In Level 4 there is a possibility of human intervention if something goes wrong with the system, however that is not the case with Level 5 autonomy. 

Real world example: Waymo cars currently in testing across the U.S. 

Level 5: 

No human driver.  Full Automation. AKA self-driving or fully autonomous. 

There is zero driver intervention in all circumstances. Everyone in the car is a passenger, and drivers are not necessary. Steering wheels probably aren’t required. Envision a new-age taxi system to get you from point a to point b without a human driver. 

Real world example: Zoox, Waymo, Lyft et al. are busy building these vehicles. At this time, only beta vehicles or remotely controlled robo taxis exist. From what we know, in all of these cases, humans are surveilling the drives remotely and can take over the drive via direct computer access if needed.