Expert Focus Group on Driver Distraction:

Transcription

1 Expert Focus Group on Driver Distraction: Definition and Research Needs US EU Bilateral ITS Technical Task Force April 28, 2010 Berlin, Germany

2 Disclaimers The views expressed in this publication are those of the authors and do not necessarily reflect the European Commission's official view on the subject. Neither the European Commission not any person acting on its behalf is responsible for the use which might be made of the information contained in the present publication. The European Commission is not responsible for the external websites referred to in the present publication."

3 Introduction The US EU Bilateral ITS Technical Force was established in 2009 with the goal to promote enhanced collaboration between US and EU in research and deployment of Intelligent Transportation Systems. The Task Force (TF) identified five primary topic areas: Terminology, Assessment Tools, Application Roadmaps & Technology Issues, Standards Harmonization, and Driver Distraction. For each of these areas, small working groups (WGs) were formed with representatives from the US and EU. During the Task Force meeting in Washington DC, January 2010, the Distraction WG proposed a Focus Group meeting with a small group of selected experts, three from each continent, with the general objective to provide input to the Bilateral TF on future, potentially collaborative, research activities on distraction. The Focus Group was held in Berlin, Germany on April 28, 2010 with conveners from the US and EU working with the three driver distraction experts from each continent. The conveners, Johan Engström (Volvo), Stephanie Binder (NHTSA), and Chris Monk (FHWA), worked with the experts during one day to address the two primary objectives as laid out by the Distraction WG. Participants Objectives US Participants EU Participants Richard Hanowski VTTI Michael Regan INRETS Bill Horrey Liberty Mutual Alan Stevens TRL John Lee U. of Wisconsin Trent Victor Volvo One key issue in driver distraction research is a lack of a commonly accepted definition of the phenomenon of interest. The disparity in definition causes problems when attempting to synthesize distraction effects across studies if the experimenters use different understandings of distraction. Thus, the first objective of the Focus Group was to discuss and agree on a common definition of driver distraction. Driver distraction is a complex topic that can be addressed in a variety of ways. Accordingly, there are many research questions that need to be addressed in order to address the driver distraction problem in the most efficient way. The intense research efforts in the past decades have produced many answers, or partial answers, to some of these research questions. However, many questions remain unanswered. Therefore, the second specific objective of the Focus Group was to identify the top 10 most pressing research questions that need to be addressed in future research on driver distraction, and the type of data collection and analysis needed to answer them. By addressing these research questions, we will have a better understanding of key unknowns that may impact future versions of the definition. It is important to note that the Focus Group discussion was focused on scientific issues and countermeasure identification rather than political issues such as regulation or legislation.

4 Challenge to the experts Each expert was asked to prepare a 15 minute presentation that included the following: A short introduction to his research background in the field of driver distraction The proposed definition of driver distraction (including the reasoning behind it) The 5 prioritized research questions that they considered most important to address in order obtain a better understanding of driver distraction and how to best counteract it. The key needs for data collection and analysis linked to the identified research questions. The role of the different stakeholders (academia, industry, government) in each research need. After the presentations, the group discussed the definition options and research priorities until general consensus was reached. The key goals of the meeting were to develop (i) a definition and (ii) a list of research needs. Tangential items will be addressed at a later time. Definition of driver distraction The lack of a commonly accepted definition of distraction is problematic for several reasons. Perhaps most importantly, different definitions may lead very different estimates of driver distraction as a contributing factor in road crashes. Coming to consensus on a single, concise definition of driver distraction is no easy task. The Focus Group participants agreed that the definition needed to be succinct and straight forward to ensure greater adoption of the definition by researchers, policy makers, and the public. Each expert provided his own definition and then the group worked together to distill the options into a single, agreed upon definition. The experts generally agreed that driver distraction involves some failure in attention selection (potentially including failures related to perceptual analysis, response selection, and response processing). However, an attention selection failure may involve erroneous selection of driving related as well as non driving related objects, events, and/or actions. An example of the former would be a driver who performs a shoulder check during a lane merging maneuver and runs into a suddenly stopped lead vehicle. An example of the latter would be a driver texting on the cell phone. There may also be grayzone cases like checking the display of a navigation system, which could be regarded as driving related on a strategic level. After some discussion, it was generally agreed that the term distraction should be saved for diversion of attention from tasks that are critical to safe driving to tasks/activities that are not critical for safe driving. Thus, the driver in the merging example would not be regarded as distracted whereas the texting and the display checking drivers would. To capture this, the following definition was agreed upon:

5 Driver distraction is the diversion of attention from activities critical for safe driving to a competing activity. Whereas there was common agreement on the general formulation of the definition (which is similar to that proposed by Lee, Young, and Regan, 2008), it was clear that several more specific issues required further consideration. It was thus agreed to further complement this general definition with a set of explanatory notes, once these issues have been settled. The following were some of the key issues discussed: Activities critical for safe driving: According to the agreed definition, driver distraction refers to diversion from activities critical for safe driving. Hence, we need to be precise about what these safety critical activities are. There was a general agreement that safe driving activities are those that allow the driver to avoid or not cause a crash. However, exactly what is critical for safe driving depends on the specific situation at hand and a universally applicable list of such activities has yet to be defined (if possible at all). Moreover, when analyzing a crash scenario, we know after the fact which activities were safety critical in a particular case. Thus, there may be a hindsight bias in assigning distraction as a contributing factor. This seems to be most problematic for broader definitions that count diversion of attention to other safety critical activities (e.g., looking for other vehicles, checking traffic lights, etc.) as distraction (since what was most safety relevant can often only be assigned in hindsight). If the majority of crashes can be partly attributed to distraction after the fact, distraction may be greatly diminished in terms of explanatory power. However, the question remains how to draw the line, in an objective manner free from hindsight bias, between safety critical and non safety critical activities. Clearly, this issue needs further consideration, and impacts all estimations of distractionrelated crashes. Competing activity refers to driver engagement in the distracting task, which might involve objects inside or outside the vehicle and is not limited to interactions with technologies. Importantly, the competing activity, as defined here, is not critical for safe driving. Again, exactly what activities should be considered critical for safe driving needs further consideration as this depends on the driving context. Moreover, the perception of what is critical may differ between drivers. Distraction as a binary or continuous phenomenon: An important issue concerns whether distraction should be regarded as a binary, all or none, phenomenon (attention is either diverted or not), or whether it best viewed as a continuous phenomenon where attention can be regarded as more or less diverted to the competing activity. Here the views of the experts differed somewhat. One view was that (at least conscious) attention is either diverted or not but that the interference resulting from this diversion varies continuously, depending, for example, on driving demand, driver characteristics and the degree of self regulation in response to the diversion. The alternative view was that the degree of distraction itself varies continuously depending on driving demand and driver characteristics. Clearly, this issue requires further discussion.

6 Distraction thresholds: Specifying the degree of distraction or interference that poses a reliable threat to safety, considering both the momentary and total time the eyes and mind (and perhaps also hands and feet) are diverted from the driving task, is desirable. However, exactly how such a threshold could be operationalised, and for what purpose (e.g., regulation or product evaluation), is still an open issue. Does distraction require the presence of a triggering event? Here the opinions of the experts were again somewhat mixed. Some argued that the presence of an external (exogenous) trigger makes the difference between true distraction and daydreaming and general internal thoughts. However, others wanted to include daydreaming and internal thoughts in the scope of distraction. The current definition supports the second approach, thus including daydreaming and general internal thoughts as diversions of attention from activities critical for safe driving. Distraction and volition: Opinions were also mixed regarding whether distraction can or cannot be voluntary. Whereas some argued that distraction should be limited to involuntary activities, others argued that this would exclude many driver initiated activities such as texting from distraction, which would clearly be in conflict with the layperson s view of distraction. Moreover, it may be difficult to define unambiguously what is voluntary and what is not. Other types of attention related failures : Even if excluded from the proposed definition of distraction, competition for attention between activities critical to safe driving is a very important issue as it is a key mechanism behind crashes (as demonstrated, for example, by the relatively frequent eyesoff road crashes and near crashes in the 100 car study). As an example, consider again the distinction between rear end crashes caused by looking over the shoulder (an activity critical for safe driving) versus looking at a cell phone (non critical and therefore distracting). It could be argued that diversion of attention towards other activities relevant for safe driving are not really failures, but just the natural outcome of managing a multi task environment (see Moray, 2003; it is also interesting to think of how collision warnings would mitigate or exacerbate this sort of situation). In any case, these types of general inattention related factors need to be accounted for in research and crash/incident analysis. Issues such as fatigue and poor hazard awareness in young drivers and UFOV and age related cognitive decline in older people should also be addressed. Subsequent to the meeting, a discussion on how to classify different types of inattention related factors continued in post meeting s. This topic needs to be followed up thoroughly as it is critical for consistent classification of attention related failures in upcoming field operational tests and naturalistic driving studies on both sides of the Atlantic. Common Research Needs Once a generally agreed upon definition of driver distraction was achieved, the Focus Group members turned their attention to the most pressing research needs related to driver distraction. The following list was generated based on each expert s individual list, from which the top 10 topics were selected as a group. Research needs are not ordered by priority, but range from defining metrics to assessing the impact of distraction types.

7 1. Determine which performance indicators best define crash risk (includes modeling). Specifically, which metrics should be used when analyzing laboratory and naturalistic driving data? This will facilitate more robust comparisons between studies. 2. Identify and develop standardized test or experimental procedures to be used across studies to measure the impact of distraction on activities critical for safe driving. These procedures should include: a. Reliable, objective measures b. Reproducible analytic and empirical methods c. Factors (e.g., roadway, etc.) that matter most in terms of safety This too will facilitate more robust comparisons between studies. 3. Determine the generalizability of different methods and how to improve them. This determination would specifically address the differences between laboratory (including parttask and simulator), test track, and naturalistic studies, addressing ecological and external validity. 4. Investigate drivers willingness to engage and disengage in distracting activities. Consideration should be given to different driver groups, how engaging and disengaging is related to behavior regulation and change, and how social norms influence willingness to engage and how such norms may be changed over time (e.g., socially accepted risk). 5. Investigate cognitive distraction, specifically its definition, categorization, and relationship to other types of distraction, measurement, and impact/real world implications. 6. Determine the risk associated with different, technology and non technolology related, activities. Of particular interest are: a. Exposure, including willingness to engage; b. Workload from both the driving task and competing task; c. Individual differences; d. Multitasking strategies and self regulation; and e. Taxonomies for defining and coding driver engagement in distracting activities. 7. Given the range of distracting tasks, determine the most effective countermeasures for preventing driver distraction and mitigating its effects. 8. Investigate distractions outside of the vehicle, including potential sources of distraction from infrastructure elements (e.g., advertizing on variable message signs) as well as roadside

8 elements unrelated to driving (e.g., billboards). Appropriate scope of these distraction sources should be considered in light of their impacts on safety and the ability to offer countermeasures. 9. Examine the work induced distractions and activities that drivers and other road users (e.g., pedestrians and bicyclists) engage in across transportation modes. These activities include checking voic , , and other activities directly related to one s job. 10. Explore the impact of cognitive underload and the potentially protective effects of distracting activities. There are thresholds for overload and underload (i.e., under stimulation, boredom) that need to be considered. Some driving contexts that are similar to vigilance tasks (i.e., tasks that require prolonged, sustained attention) are prone to underload and therefore may actually benefit from additional activities that would be distracting in other circumstances. The Focus Group members also noted the need to share information on inattention research in general, particularly concerning modern attention theory. There has been a history of driver distraction researchers employing simple information processing theories of attention, disregarding both seminal studies in basic attention research and more contemporary, neurologically grounded models and theories. In addition, this focus on the attentional processess of the driver needs to be balanced with a focus on the rapid changes in the range of potential distractions, and in the increasingly sophisticated attentional processes being developed for vehicles in the form of collision warning and vehicle control systems. The attentional capacity of the joint driver vehicle cognitive system is likely to have emergent properties that could have substantial consequences for driving safety. References Lee, J.D, Young, K L. and Regan, M.A. (2008). Defining Driver Distraction. In Regan, M.A., Lee, J.D. & Young, K. (Eds) (2008). Driver distraction: Theory, Effects and Mitigation. Florida, USA: CRC Press (Chapter 3) Moray, N. (2003). Monitoring, complacency, scepticism and eutactic behaviour. International Journal of Industrial Ergonomics, 31(3),