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

<div class="section abstract"> <div class="htmlview paragraph">This Recommended Practice provides a taxonomy for motor vehicle <i>driving automation systems</i> that perform part or all of the <i>dynamic driving task</i> (<i>DDT</i>) on a <i>sustained</i> basis and that range in level from <i>no driving automation</i> (level 0) to <i>full driving automation</i> (level 5). It provides detailed definitions for these six levels of <i>driving automation</i> in the context of <i>motor vehicles</i> (hereafter also referred to as “<i>vehicle</i>” or “<i>vehicles</i>”) and their <i>operation</i> on roadways. These level definitions, along with additional supporting terms and definitions provided herein, can be used to describe the full range of <i>driving automation features</i> equipped on <i>motor vehicles</i> 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 users of <i>vehicles</i> of all classes and <i>driving automation</i> levels (including no <i>driving automation</i>), as well as motorcyclists, pedal cyclists, and pedestrians.</div> <div class="htmlview paragraph">The levels apply to the <i>driving automation feature(s)</i> that are engaged in any given instance of on-road <i>operation</i> of an equipped <i>vehicle</i>. As such, although a given <i>vehicle</i> may be equipped with a <i>driving automation system</i> that is capable of delivering multiple <i>driving automation features</i> that perform at different levels, the level of <i>driving automation</i> exhibited in any given instance is determined by the <i>feature(s)</i> that are engaged.</div> <div class="htmlview paragraph">This document also refers to three primary actors in <i>driving</i>: the (human) <i>driver</i>, the <i>driving automation system</i>, and other <i>vehicle</i> systems and components. These other <i>vehicle</i> systems (or the <i>vehicle</i> in general terms) do not include the <i>driving automation system</i> in this model, even though as a practical matter a <i>driving automation system</i> may actually share hardware and software components with other <i>vehicle</i> systems, such as a processing module(s) or operating code.</div> <div class="htmlview paragraph">The levels of <i>driving automation</i> are defined by reference to the specific role played by each of the three primary actors in performance of the <i>DDT</i>. “Role” in this context refers to the expected role of a given primary actor, based on the design of the <i>driving automation system</i> in question and not necessarily to the actual performance of a given primary actor. For example, a <i>driver</i> who fails to <i>monitor</i> the roadway during engagement of a level 1 adaptive cruise control (ACC) system still has the role of <i>driver</i>, even while s/he is neglecting it.</div> <div class="htmlview paragraph"><i>Active safety systems</i>, such as electronic stability control and automated emergency braking, and certain types of driver assistance systems, such as lane keeping assistance, are excluded from the scope of this <i>driving automation</i> taxonomy because they do not perform part or all of the <i>DDT</i> on a <i>sustained</i> basis and, rather, merely provide momentary intervention during potentially hazardous situations. Due to the momentary nature of the actions of <i>active safety systems</i>, their intervention does not change or eliminate the role of the <i>driver</i> in performing part or all of the <i>DDT,</i> and thus are not considered to be <i>driving automation</i>.</div> <div class="htmlview paragraph">It should, however, be noted that crash avoidance features, including intervention-type <i>active safety systems</i>, may be included in <i>vehicles</i> equipped with <i>driving automation systems</i> at any level. For <i>ADS</i>-equipped <i>vehicles</i> (i.e., levels 3-5) that perform the complete <i>DDT</i>, crash avoidance capability is part of <i>ADS</i> functionality.</div></div>