Driving is primarily a visual task in which drivers are required to monitor the road scene for potential hazards and navigate to their destination. In-vehicle information systems, such as route guidance systems and in-car entertainment systems impose additional visual demands, which could distract the driver from safe vehicle control. The level of distraction imposed by an IVIS task is dependent on the quantity of information and resumability of the task as components of visual demand, as well as driver behaviour. Although it is difficult to control driver behaviour, the quantity of information and resumability associated with an IVIS task can be controlled for through the system's design. The occlusion technique is a practical method being developed to measure the visual demand imposed by in-vehicle tasks and whether a task can be resumed having been interrupted. There are numerous factors and variables that need to be controlled to ensure that results across occlusion studies are comparable. The research presented in this report aimed to address some of these issues including: a method of accounting for system response delay; the level of training; the number of repetitions on each task; the sample size and the procedure for calculating the resumability. This report details the methodology used during the trial, how the results obtained were analysed and the findings. The report also considers the suitability of the various variables (e.g. errors, total task times) in assessing IVIS tasks. Findings from the study are discussed in terms of future application of the occlusion technique to assess in-vehicle information systems.
Samenvatting