J3016_202104 Taxonomy and Definitions for Terms Related to Driving Automation Systems for On-Road Motor Vehicles



Issuing Committee
This document describes [motor] vehicle driving automation systems that perform part or all of the dynamic driving task (DDT) on a sustained basis. It provides a taxonomy with detailed definitions for six levels of driving automation, ranging from no driving automation (Level 0) to full driving automation (Level 5), in the context of [motor] vehicles (hereafter also referred to as “vehicle” or “vehicles”) and their operation on roadways:
  1. Level 0:
    No Driving Automation
  2. Level 1:
    Driver Assistance
  3. Level 2:
    Partial Driving Automation
  4. Level 3:
    Conditional Driving Automation
  5. Level 4:
    High Driving Automation
  6. Level 5:
    Full Driving Automation
These level definitions, along with additional supporting terms and definitions provided herein, can be used to describe the full range of driving automation features equipped on [motor] vehicles in a functionally consistent and coherent manner. “On-road” refers to publicly accessible roadways (including parking areas and private campuses that permit public access) that collectively serve all road users, including cyclists, pedestrians, and users of vehicles with and without driving automation features.
The levels apply to the driving automation feature(s) that are engaged in any given instance of on-road operation of an equipped vehicle. As such, although a given vehicle may be equipped with a driving automation system that is capable of delivering multiple driving automation features that perform at different levels, the level of driving automation exhibited in any given instance is determined by the feature(s) that are engaged.
This document also refers to three primary actors in driving: the (human) user, the driving automation system, and other vehicle systems and components. These other vehicle systems and components (or the vehicle in general terms) do not include the driving automation system in this model, even though as a practical matter a driving automation system may actually share hardware and software components with other vehicle systems, such as a processing module(s) or operating code.
The levels of driving automation are defined by reference to the specific role played by each of the three primary actors in performance of the DDT and/or DDT fallback. “Role” in this context refers to the expected role of a given primary actor, based on the design of the driving automation system in question and not necessarily to the actual performance of a given primary actor. For example, a driver who fails to monitor the roadway during engagement of a Level 1 adaptive cruise control (ACC) system still has the role of driver, even while s/he is neglecting it.
Active safety systems, such as electronic stability control (ESC) and automatic emergency braking (AEB), and certain types of driver assistance systems, such as lane keeping assistance (LKA), are excluded from the scope of this driving automation taxonomy because they do not perform part or all of the DDT on a sustained basis, but rather provide momentary intervention during potentially hazardous situations. Due to the momentary nature of the actions of active safety systems, their intervention does not change or eliminate the role of the driver in performing part or all of the DDT, and thus are not considered to be driving automation, even though they perform automated functions. In addition, systems that inform, alert, or warn the driver about hazards in the driving environment are also outside the scope of this driving automation taxonomy, as they neither automate part or all of the DDT, nor change the driver’s role in performance of the DDT (see 8.13).
It should be noted, however, that crash avoidance features, including intervention-type active safety systems, may be included in vehicles equipped with driving automation systems at any level. For automated driving system (ADS) features (i.e., Levels 3 to 5) that perform the complete DDT, crash mitigation and avoidance capability is part of ADS functionality (see also 8.13).
This revision of SAE J3016 was undertaken in close cooperation between the SAE On-Road Automated Driving (ORAD) Committee and ISO TC204/WG14 through a Joint Working Group formed in 2018. This collaboration brought to bear the knowledge and expertise of global experts in driving automation technology and safety. Several new terms and definitions have been added and multiple corrections and clarifications have been made to address frequently misunderstood concepts and improve the utility of the document, especially for non-native English speakers. As in the previous version, it provides a taxonomy describing the full range of levels of driving automation in on-road motor vehicles and includes functional definitions for advanced levels of driving automation and related terms and definitions. This document does not provide specifications, or otherwise impose requirements on, driving automation systems (for further elaboration, see 8.1). Standardizing levels of driving automation and supporting terms serves several purposes, including:
  1. 1
    Clarifying the role of the (human) driver, if any, during driving automation system engagement.
  2. 2
    Answering questions of scope when it comes to developing laws, policies, regulations, and standards.
  3. 3
    Providing a useful framework for driving automation specifications and technical requirements.
  4. 4
    Providing clarity and stability in communications on the topic of driving automation, as well as a useful short-hand that saves considerable time and effort.
This document has been developed according to the following guiding principles; namely, it should:
  1. 1
    Be descriptive and informative rather than normative.
  2. 2
    Provide functional definitions.
  3. 3
    Be consistent with current industry practice.
  4. 4
    Be consistent with prior art to the extent practicable.
  5. 5
    Be useful across disciplines, including engineering, law, media, and public discourse.
  6. 6
    Be clear and cogent and, as such, it should avoid or define ambiguous terms.
The document reflects lessons learned from various stakeholder discussions, as well as from research projects conducted in Europe and the United States by the AdaptIVe Project and by the Crash Avoidance Metrics Partnership (CAMP) Automated Vehicle Research (AVR) Consortium, respectively.
Italicized terms used in this document are also defined herein. Bracketed text within a term name indicates optional inclusion when using the term (i.e., bracketed text may be unnecessary, given the usage context).
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SAE International Recommended Practice, Taxonomy and Definitions for Terms Related to Driving Automation Systems for On-Road Motor Vehicles, SAE Standard J3016_202104, Revised April 2021, Issued January 2014, https://doi.org/10.4271/J3016_202104.
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Apr 30, 2021
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Recommended Practice