ISO 17488:2016

INTERNATIONAL ISO
STANDARD 17488
First edition
2016-10-01
Road vehicles — Transport
information and control systems
— Detection-response task (DRT)
for assessing attentional effects of
cognitive load in driving
Véhicules routiers — Systèmes d’Information et de commande du
transport — Tâche de Détection-Réponse (DRT) pour l’évaluation des
effets attentionnels de la charge cognitive lors de la conduite
Reference number
©
ISO 2016
© ISO 2016, Published in Switzerland
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ii © ISO 2016 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Abbreviated terms . 5
5 DRT methodology: Principles and overview . 5
6 Measurement methods and procedures . 6
6.1 Participants . 6
6.2 Experimental setup . 6
6.2.1 Non-driving experimental setup . 6
6.2.2 Surrogate driving experimental setup . 6
6.2.3 Driving simulator experimental setup . 6
6.2.4 On-road experimental setup . 6
6.3 Stimulus presentation. 6
6.3.1 Stimulus presentation timing . 7
6.3.2 Visual stimulus specifications . 8
6.4 Response method .10
6.5 Primary driving task .11
6.6 Instructions to participants .11
6.7 Training procedure .11
6.7.1 Secondary task training .12
6.7.2 DRT training .12
6.7.3 Primary task training .12
6.7.4 Training on multitasking .12
6.8 Performance measures .12
6.9 Analysing and interpreting DRT performance data .13
6.10 Checking data quality .13
6.11 Use of DRT data in decision making .14
Annex A (normative) Rationale .15
Annex B (normative) Guidelines for selecting between variants of the DRT method .23
Annex C (normative) Additional factors affecting DRT performance .25
Annex D (informative) DRT variants .27
Annex E (informative) Summary of results from the ISO-coordinated studies .38
Bibliography .69
Foreword
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The committee responsible for this document is ISO/TC 22, Road vehicles, Subcommittee SC 39,
Ergonomics.
iv © ISO 2016 – All rights reserved

Introduction
Driving is a complex task consisting of a range of sub-tasks such as keeping the vehicle in the lane,
avoiding other traffic and obstacles, observing road signs and signals, planning and initiating specific
manoeuvres, scanning mirrors and navigating. In addition, drivers often engage in secondary tasks, not
directly related to driving, such as operating the media player, conversing on the phone and reading
road-side commercial signs.
These different activities place varying, and sometimes conflicting, demands on the driver. In order to
manage the various driving and secondary tasks, the driver thus needs to allocate different resources,
such as the eyes, hands, feet, perceptual systems, motor control systems and higher level cognitive
functions, to the different sub-tasks in a dynamic and flexible way. This allocation of resources to
driving and non-driving activities may be generally conceptualized as driver attention. In most driving
situations, attention is determined by an interaction of proactive (top-down, endogenous) processes
based on anticipation of how the upcoming situation will develop and bottom-up processes (driven by
exogenous stimuli) which can trigger attention to the situation when it does not develop as expected,
even leading to a corrective action.
There is a need for methods that can be used to assess how engagement in secondary tasks affects driver
attention. In general, the effect of a task on attention depends on the amount and type of resources
demanded by the task. As outlined in further detail in Annex A, resources can be conceptualized at
three general levels: sensory-actuator resources, perceptual-motor resources and cognitive resources.
Sensory/actuator resources refer to the basic interfaces between the driver and the environment used
to sense the environment and perform overt actions. Examples include the eyes, the ears, the skin, the
feet, the hands, the mouth, the vocal cords, etc. Perceptual/motor resources can be regarded as brain
functions for controlling specific perceptual-motor activities, e.g. visual perception, manual tracking
and hand-to-eye coordination. Finally, cognitive resources refer to brain systems implementing higher-
level cognitive operations such as planning, decision making, error detection, sustaining information
in working memory, dealing with novel or difficult situations and overcoming habitual actions. These
types of high-level cognitive functions may be conceptualized in terms of cognitive control. While
sensory-actuator and perceptual-motor resources are, at least to some extent, modality-specific,
cognitive control can be regarded as a single resource with strongly limited capacity, not associated
with any particular sensory modality. Cognitive load thus refers specifically to the demand for cognitive
control that a task imposes on the driver.
Several existing and draft ISO standards address the assessment of secondary task demand in the
[1] [2]
context of driving. ISO 15007-1 and ISO/TS 15007-2 provide guidance on how to measure glance
[3]
behaviour and ISO 16673 focuses exclusively on the viewing time required to perform a task using an
in-vehicle information system. Hence, these methods focus mainly on the assessment of (visual) sensory
[4]
demand (i.e. the demand for the eyes). ISO 26022 provides a technique for evaluating the combined
effect of sensory-actuator, perceptual-motor and cognitive demands on a driver’s performance in a
combined event detection and vehicle control task.
However, a standardized measurement method that specifically addresses cognitive load is lacking.
While, for example, ISO 26022 is sensitive to cognitive load, it lacks specificity since its main
performance metric (MDEV) is also sensitive to visual sensory motor interference (i.e. visual time
sharing; see Annex A). A standardized method specifically addressing cognitive load is particularly
needed in order to evaluate the attentional demands of new driver-vehicle interfaces designed to
minimize visual interaction such as voice-based interfaces, haptic input devices and head-up displays.
The detection-response task (DRT) method defined in this document intends to fill this gap. More
specifically, the DRT is mainly intended to measure effects of the cognitive load of a secondary task on
attention. However, some versions of the DRT specified in this document may also be used to capture
other forms of secondary task demand (e.g. visual sensory demand). The general rationale behind the
DRT methodology is further outlined in Annex A.
Annex B provides guidance on how to select among the different DRT versions defined in this
document. Annex C reviews factors that could potentially affect DRT performance and thus need to be
accounted for when designing DRT experiments. Annex D offers a review of existing alternative DRT
methodologies not covered by thi
...