SAE International Issues Updated Chart to Clarify Vehicle Autonomy Levels

But will the changes be enough to stop the rampant confusion amongst consumers and automakers?

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Not all self-driving cars are created equal. SAE International's autonomy scale has become the de facto way for explaining the capabilities of individual vehicles. But the scale, which ranges from Level 0 (100-percent human control) to Level 5 (full autonomy) can be ambiguous, which is why SAE International issued an updated chart clarifying the meanings of some of the levels.

The chart was meant to more clearly explain the autonomy levels to consumers, an SAE International press release said. Zero automation and full automation don't take much explaining, but the levels in between can be a bit murky. For example, both Level 2 and Level 3 cars have some degree of automation, but can't drive themselves. Yet what separates the two levels hasn't always been clear.

SAE International hopes to address this by definitively separating Levels 0 through 2 and Levels 3 to 5 into separate groups. In the former, the human driver is responsible for controlling the vehicle at all times, according to SAE International. Levels 3 to 5 include features that allow the car to take over driving at least some of the time, the group said.

The new chart also specifically tells human drivers what they need to do. For Levels 0 to 2, drivers must "constantly supervise" the vehicle and "steer, brake, or accelerate as needed to maintain safety." For Level 3, drivers must be prepared to take over "when the feature requests," meaning when the car is not capable of completely controlling the steering, throttle, or brakes. Levels 4 and 5 "will not require" human involvement in most cases, according to the chart.

SAE International also included examples of features that correspond to each level. A car is still considered Level 0 even if it has some driver aids, like blind-spot monitoring and lane-departure warning. Adaptive cruise control is considered a Level 1 feature, but when combined with automated lane centering (as in Tesla's Autopilot or Nissan's ProPilot Assist), that bumps things up to Level 2. The only specific Level 3 feature mentioned is "traffic jam chauffeur," which may refer to systems like Audi's Traffic Jam Pilot, which can handle acceleration, braking, and steering in stop-and-go traffic.

Level 4 and Level 5 refer to cars that can drive with no human intervention; the main difference is that Level 4 cars may have backup manual controls. While SAE International's clarifications could prove helpful to car buyers, continuing to describe fully autonomous cars on the same spectrum as human-driven cars equipped with assist features could still lead to confusion over the limitations of driver aids.

Hyundai Nexo Prototype with Level 4 Autonomous Capabilities
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