Levels of Automation for Autonomous Ground Vehicles
Self-driving cars research and development have been the focus of attention for the last decade or so. The main reason behind it is that automated driving is expected to improve safety, optimize traffic flow, help reduce fuel consumption, CO2 emissions and much more. This brought the need for a taxonomy and standard that defines different levels of automation. Society of Automotive Engineers (SAE) was one of the first internationally recognized organizations to release such standard under the name J3016. However US National Highway Traffic Safety Administration (NHTSA) and German Federal Highway Research Institute (BASt) have also slightly different levels of automation definition of their own. Understanding and differentiating between different levels of automation can be difficult specially for the mid levels. I’ll try to explain these levels according to SAE J3016 standard in simple terms. Finally I’ll show the correspondence between the SAE levels and the NHTSA and BASt levels.
SAE Levels:
According to SAE J3016 there are six different levels of automation from level 0 (no automation) to level 6 (full automation). Here’s the summary:
Level 0 (No Automation):
In this level the human driver is responsible for all the driving tasks including control of the car in both longitudinal (acceleration/deceleration) and lateral (steering) ways as well as monitoring the road and environment around the car.
Level 1 (Driver Assistance):
In this level the agent (automated system) will take care of controlling the car in either longitudinal (acceleration/deceleration) or lateral (steering) but not both.
Level 2 (Partial Automation):
In this level the agent will take care of both longitudinal (acceleration/deceleration) and lateral (steering) control of the car.
Level 3 (Conditional Automation):
In levels 0–2 human driver was solely responsible for monitoring the road and environment around the car. But for levels 3–5 this monitoring task is done by the automated driving system. Level 3 is level 2 with agent monitoring the driving environment.
Level 4 (High Automation):
In this level not only the agent controls the car in both longitudinal and lateral directions. and monitors the driving environment but also is capable of handling any failure in case the automated driving system fails. Note that Level 4 automated vehicles can handle some driving modes that’s why they’re referred to as high automation not full automation.
Level 5 (Full Automation):
Level 5 is the highest level and describes fully autonomous car i.e. robot taxis. The difference between level 5 and level 4 is that level 5 vehicles can navigate and handle all different sorts of driving modes, different driving conditions and roads autonomously without the need for human driver interaction.
Other Automation Levels:
Now that you got a better understanding of SAE levels of automation, lets compare them with the corresponding NHTSA (US) and BASt (Germany) levels int the table below:
As you can see both NHTSA and BASt have five levels instead of the SAE six. NHTSA considers both high automation and full automation as one level of full self-driving automation. BASt is similar to SAE except that they don’t consider conditional automation as a separate level.
References:
SAE J3016, SAE International, NHTSA, BASt, S. Grubmüller et al., Vox
