Development of Guidelines for In-Vehicle Information Presentation: Text vs. Speech

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Virginia Tech


The demand for in-vehicle information systems (IVIS) has been increasing through the years. There are numerous systems that can be incorporated into vehicles and various ways in which the information can and should be presented to the driver. The way the information is presented to the drivers is extremely important in terms of increasing safety and decreasing driver distraction. The expected outcomes of this research included the development of human factors guidelines for the design and use of in-vehicle information systems. It was a desirable goal to identify the most suitable information presentation formats for certain tasks, since this may influence the drivers' attention and driving performance. This study focused on how the factors of interest may affect drivers' attention and driving performance while performing IVIS secondary tasks related to specific applications. This was accomplished through an on-road within-factors experiment. Sixteen participants performed secondary tasks related to three IVIS applications at two levels of difficulty. The tasks were presented using five types of displays. Data collected from video and in-vehicle sensors were statistically analyzed to determine significant effects between the factors. Driving performance, external reaction time, and perceived mental workload results were compiled into general guidelines for the design and use of IVIS. The findings of this study strongly suggest that visual displays should not be used for the presentation of IVIS. Auditory and multi-modal (i.e. both visual and auditory interface) displays are the most appropriate ways to present IVIS information. A normal speech rate is preferred over a fast speech rate. IVIS tasks should be kept as simple as possible in terms of the number of steps. From the three manipulated factors (type of display, IVIS application, and task level of difficulty), the type of display had the largest number of significant results across the dependent variables measurements. The visual display led to the worst driver performance, while auditory and multi-modal displays yielded significantly better driving performance.



Transportation Safety, Information Displays, Driving Performance, In-Vehicle Information Systems