Drivers sometime report a feeling of `waking up' while driving and having no clear recollection of the preceding road environment. Such reports have been variously described as time-gap experiences, highway hypnosis and driving without attention mode. In this study we used questionnaires to explore the frequency with which subjects report experiencing such events and attempted to relate such reports to performance on laboratory tests. Subjects completed the Driver Behaviour Questionnaire, the Cognitive Failures Questionnaire and a specific time gap questionnaire and performed two additional vigilance tasks. The first of these was an artificial task which required the monitoring of two lines on a computer screen, while the second was a video-based motorway driving task in which the driver had to remain vigilant for unpredictable infrequent events. As well as performance measures we also recorded the rate of self-reported Task-Unrelated Images and Thoughts (TUITs) in subjects while they performed each of the tasks. Interrelationships between these measures and subjective reports of time-gaps while driving are discussed. We found a variety of strong relationships between performance measures and the questionnaire responses. Subjects who reported frequent time-gaps while driving had lower hit rates, slower reaction times and more TUITs than those who reported fewer time gaps in everyday driving. Interestingly these relationships only emerged clearly once the vigilance tasks had been in progress for more than 15 minutes. These results support the hypothesis that time-gaps while driving represent a real phenomenon with potential implications for accident involvement. (A)
Samenvatting