ISO 17488:2016 provides a detection-response task mainly intended for assessing the attentional effects of cognitive load on attention for secondary tasks involving interaction with visual-manual, voice-based or haptic interfaces. Although this document focuses on the assessment of attentional effects of cognitive load (see Annex A), other effects of secondary task load may be captured by specific versions of the DRT, as further outlined in Annex B. Secondary tasks are those that may be performed while driving but are not concerned with the momentary real-time control of the vehicle (such as operating the media player, conversing on the phone, reading road-side commercial signs and entering a destination on the navigation system).
NOTE According to this definition, secondary tasks can still be driving-related (such as in the case of destination entry).
ISO 17488:2016 does not apply to the measurement of primary (driving) task demands related to the momentary real-time control of the vehicle, such as maintaining lane position and headway or responding to forward collision warnings. However, this does not preclude that the DRT method, as specified in this document, may be adapted to measure such effects.
ISO 17488:2016 applies to both original equipment manufacturer (OEM) and after-market in-vehicle systems and to permanently installed, as well as portable, systems.
It is emphasized that, while the DRT methodology defined in this document is intended to measure the attentional effects of cognitive load, it does not imply a direct relationship between such effects and crash risk. For example, taking the eyes off the road for several seconds in order to watch a pedestrian may not be very cognitively loading but could still be expected to strongly increase crash risk.
Furthermore, interpret DRT results cautiously in terms of demands on a specific resource, such as cognitive load. Specifically, if the goal is to isolate the effect related to the cognitive load imposed by a secondary task on attention, avoid overlap with other resources required by the DRT (e.g. perceptual, motor, sensory or actuator resources). A particular concern derives from the fact that the DRT utilizes manual responses (button presses). Thus, for secondary tasks with very frequent manual inputs (on the order of one or more inputs per second), increased response times on the DRT may reflect this specific response conflict (which is due to the nature of the DRT) rather than the actual cognitive load demanded by the task when performed without the DRT (i.e. alone or during normal driving; see Annex E). Thus, for such response-intensive tasks, DRT results are interpreted with caution. This document defines three versions of the DRT and the choice of version depends critically on the purpose of the study and the conditions under which it is conducted (see Annexes A and B for further guidance on this topic).
ISO 17488:2016 specifically aims to specify the detection-response task and the associated measurement procedures. Thus, in order to be applicable to a wide range of experimental situations, this document does not define specific experimental protocols or methods for statistical analysis. However, some guidance, as well as examples of established practice in applying the DRT, can be found both in the main body of this document and in the annexes (in particular Annexes C and E).