Automakers are still years away from the ideal of fully autonomous, self-driving vehicles, but significant progress toward that goal is evident today.
The Society of Automotive Engineers (SAE) defines six levels for autonomous vehicles and these are intended as short hand for a given vehicle’s level of automation. The self-designated levels range from Level 0 (no automation) to Level 5 (able to operate under any conditions that a human driver could). With Levels 0-2, human drivers monitor the driving environment. With Levels 3-5, the automated driving system monitors the driving environment. The levels are designated by the maker of a system; they’re not assigned by an outside agency. It is also worth noting that a particular vehicle may have multiple driving automation features such that it could operate at different levels depending upon the individual features that are enabled.
So where are we now?
Level 0 is defined as no automation and would pretty much cover every commercial vehicle produced through last year. SAE says that the human provides the “dynamic driving task” although there may be systems in place to help the driver. An example would be the emergency braking system. Since it does not “drive” the vehicle it would not qualify as automation.
Level 1 is defined as driver assistance. Here a system provides either steering or acceleration assistance such as cruise control. Adaptive cruise control, where the vehicle can be kept a safe distance behind the next car, qualifies as Level 1 because the human driver monitors other aspects of driving such as steering and brakes.
Level 2 is defined as advanced driver assistance systems. Here the automation falls short of self-driving because a human remains in the driver seat and can take control of the car at any time. Both Tesla’s Autopilot and General Motors’ Super Cruise systems qualify as Level 2.
The leap from Level 2 to Level 3 is substantial from a technological perspective, yet subtle from a human perspective. The primary operation of the vehicle effectively shifts from the human driver to an automated system. In both levels the degree of automation is limited.
Level 3 is defined as “conditional automation.” This means a vehicle can drive itself but only under strictly limited circumstances (such as only on a highway). Like Level 2, Level 3 systems require a human driver to be alert and ready to take control quickly, however the design in this higher level emphasizes that the system controls the vehicle, not the human. While some automakers have stated they will skip Level 3, possibly because it is a variation on Level 2, Volkswagen’s Audi is rolling out its first Level 3 vehicles in 2018.
When talking about self-driving vehicles, Level 4 (or “high automation”) is the goal for most automakers. Like Level 3, Level 4 means a vehicle system can do most of what a human driver can do, but here the limitation is a geographic area, such as an urban area. Most of the ride-sharing or vehicle-for-hire autonomous vehicle systems likely to come to market soon will be Level 4 systems.
Alphabet’s Waymo already has a Level 4 vehicle. Navya, a French company, has also rolled out the Autonum Cab, a Level 4 autonomous vehicle designed without a steering wheel, mirrors, or brakes. Canadian automaker Magna is predicting Level 4 vehicles in time for 2025. China’s Baidu is also working on Level 4 vehicles.
More still needs to be done to get to the ideal, Level 5 or full-blown autonomous driving. Here the definition is that a vehicle can go anywhere and do anything that an experienced human driver can. These will be the vehicles where you state “take me to work” and the car will handle all the details while you work on that presentation or take a conference call. This will require, among other things, improved communications networks and artificial intelligence.
Additional autonomous vehicle definitions can be found within the SAE J3016 and other SAE standards.