If you are like me, you can't wait to get yourself a self-driving car. Now, as you may already be aware, no one has one that is market ready and fully autonomous. Full autonomy is still a few years out. While, waiting for 2020 or beyond might seem too far out, I think you'll be happy to know that your car already has some autonomous capabilities. Newer models are already rolling out with incremental features. For example, just this week the 2019 Audi A8 became the first car to support level-3 self driving capabilities. You'll be able to get your hands on one of these starting in 2018.

If you are wondering what does level-3 mean? Or how do we define "full" autonomy Or when will we get there? please read on. 

In this post

In this post, I'll cover the basic levels of autonomy for a system that controls a car or vehicle (Note my careful choice of words here). The autonomy rating is for the system that controls the car and not the car itself. These levels are defined by SAE [1] to provide a consistent way for referring to how autonomous a system is. The taxonomy is also limited to on-road motor vehicles only. In other words, it doesn't apply to things that fly or sail or go off-road. 

If your car is relatively new, you'll be surprised to see that it does indeed already contain some autonomy features. I'll cover some work horses (like cruise control) and new and trendy favorites (like autosteer+ and smart summon in Tesla and traffic jam pilot in Audi).

The six levels of automation

There are six levels (level-0 through level-5) that go from no automation through full automation. The differences are mostly along two dimensions: awareness and control. In the first three levels, the human driver monitors the driving environment while the car gradually picks up control. In the last three, the automated driving system also takes over monitoring the driving environment. Driving environment here refers to the traffic on the road and any potentially risky scenarios like road construction and safety zones, presence of emergency vehicles, railroad crossings, etc.

The typical activities that determine SAE level are (a) monitoring (of the driving environment), (b) steering, and (c) acceleration/deceleration. When the automated driving system is only doing some of the work, the human driver needs to be alert and be ready to take over. The system is capable of being autonomous in certain modes and will back off to the human driver when it can no longer safely be autonomous. Not all driving scenarios are equally difficult. Driving modes categorize these for easy reference and incremental delivery of autonomous capabilities. Some example driving modes are: high speed cruising, low speed traffic jam, expressway merging, closed-campus operations, etc. 

The below chart from SAE provides definitions:

The most important is the transition from level 2 (partial automation) to level 3 (conditional automation). Starting at level 3, the automated driving system starts to take over the entire driving task under certain driving modes.

 At level 0, the human pretty much does everything. The system does nothing, no monitoring, no control.

At level 1, under certain driving modes, either the steering wheel or the accelerator & brakes are controlled by the system, but NOT both. All other work is done by the human, especially monitoring the driving environment.

At level 2, under certain driving modes, BOTH the steering wheel and accelerator & brakes are controlled by the system. The biggest difference between level 1 and level 2 is that the system is now able to perform (steering, acceleration, braking) together. All other work is done by the human, especially monitoring the environment. There is not a big difference between level 1 and level 2. 

At level 3, under certain driving modes, the system monitors the environment and takes control of the steering wheel, accelerator, and brakes. However, when the system encounters a scenario that it cannot handle, it backs off to the human, who must be ready to take control of the vehicle appropriately. As the system is monitoring the environment, it is able to determine when it is safe for it to control the vehicle and when to fall back to the human.

At level 4, under certain driving modes, the system is able to safely handle the dynamic driving task, even when a human driver does not respond appropriately, e.g. turn blinkers on and safely come to a stop or pull over to the side. This means that the human really doesn't have to be paying attention anymore, though if the car does bail on the driving task and come to a safe stop, they'd need to pick up from there.

At level 5, the system does all of the driving. At this point, cars won't need steering wheels, brake pedals, accelerator pad, windshields, etc. They also won't need humans for driving!

One liner: Feet off, Hands off, Eyes off, Brain off or Body out

Mercedes and BMW have simplified referring to these levels by calling them Feet Off (level 1), Hands Off (level 2), Eyes Off (level 3), and Brain Off or Body Out (level 4 & 5).

What level of autonomy is your car at?

Now that we have the abstract definitions of the six levels down, how do you go about determining your car's autonomy level? Here are some car features to determine that. 

If you have driver assistance features like cruise control, anti-lock brakes (ABS), or automatic emergency braking (AEB) then you are already at level 1. AEB is referred to by several different names depending on the car maker. For example, it is called the Collision Mitigation Braking System (CMBS) by Honda and Pre-Crash Safety System (PCSS) by Toyota.

You move from driver assistance to partial automation if your car can do multiple driver assistance functions at once. So, when features like adaptive cruise control combined with autosteer are available in your car, it has reached level 2. Tesla autopilot (hw1.0) is level 2, while the upcoming hw2.0 promises level 3 with future software upgrades. The 2019 Audi A8 is the first production car to support level-3 self driving capabilities. Some level 3 features in these cars include traffic jam pilot, automatic lane changes, and transitions from one freeway to another without requiring driver input. The traffic jam pilot manages starting, accelerating, steering, and braking functions of the car. It can be activated in slow moving traffic (less than 60 km/h = 37.3 miles/hr) on freeways and highways where a physical barrier separates the two carriageways. One interesting feature of the Audi A8's traffic jam pilot vs Tesla Model S' autopilot is that it uses a laser scanner (LIDAR) for accurate distance measurements. This is superior to using only a combination of camera, radar, and sonar sensors that are on the Tesla Model S (Audi A8 also has these.)

Current Predictions for when we'll have these capabilities in cars

Self driving car technology isn't too far off into the future. General consensus is that if legal and social regulations don't end up being blockers, we will have Level-5 autonomous cars between 2021 (optimistic) and 2025 (pessimistic).

Here is a timeline of when these are anticipated in "many" car models:

  • 2016 - Feet Off (Level 1) features already common in the market, with some car makers providing Level 2 capabilities.
  • 2018 - Hands Off (Level 2 and level 3) capabilities expected to be common with autonomous operation for up to three minutes at a time. You'll still need to keep your hands on the wheel while monitoring the driving conditions and be ready to respond to unexpected circumstances (including machine failures).
  • 2021 - Eyes Off (Level 3 and level 4). Steering wheel will still be present.
  • 2025 - Brain Off or Body Out (Levels 4 & 5). Steering wheel becomes optional with some models simply foregoing it.

References


Kumar Chellapilla

Kumar Chellapilla

Director Of Engineering at Uber Advanced Technologies Group

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