Trying to validate subjective reports with a naturalistic driving data - a case against questionnaires and surveys to quantify driver distraction

The effects of different forms of driver distraction on driving distracting activities, however, is less clear. Available are comparatively well understood. How often drivers actually engage in different methods are either not able to provide a complete picture, or are extremely expensive. Post-drive questionnaires and surveys might provide a cheap solution to the problem. As part of a naturalistic driving pilot survey/questionnaire that is intended to capture the occurrence and duration of different secondary tasks. However, for a variety of reasons, this attempt was unsuccessful. It became clear that there was a huge discrepancy between the drivers’ naïve understandings of secondary tasks (what is it, what is part of it, how long is it, etc.) and scientific definitions of the same concepts. Further problems arose from the fact that even though questioned directly after the trip, many accounts appeared to have been reconstructions, rather than recollections of secondary task engagement. We conclude that subjective accounts of secondary task engagement are largely inappropriate to quantify driver distraction