Enhancing the occlusion technique as an assessment tool for driver visual distraction

• Published in: IET intelligent transport systems Vol. 4; no. 4; pp. 346 - 355
• Main Authors: Gelau, C., Schindhelm, R.
• Format: Journal Article
• Language: English
• Published: Stevenage The Institution of Engineering & Technology 01.12.2010
• Subjects: Assessments; Demand; Occlusion; Tasks; Tracking; Visual
• ISSN: 1751-956X; 1751-9578
• DOI: 10.1049/iet-its.2009.0115

In this context, visual occlusion technique has been developed as a tool for the assessment of the in-vehicle human-machine interface of in-vehicle information systems (IVIS) in terms of visual demands. The authors assumed that subjects would continue task performance during occluded periods leading to an underestimation of visual demands by the occlusion parameters 'total shutter open time' (TSOT) and the 'occlusion index' (R). The authors predicted that a simple additional loading task to be performed in parallel could disrupt IVIS task performance during the occluded period leading to higher estimations of visual demands by TSOT and R. This prediction was confirmed by data. These show significant increases in TSOT and R when the standard occlusion protocol was enhanced by a simple auditory tracking task to be performed in parallel. Furthermore, it could be demonstrated that under the condition of additional auditory tracking, TSOT and R discriminated more clearly between an 'easy' and a 'difficult' IVIS task than under the standard condition.