Evaluating the Usability of a Head-Up Display for Selection from Choice Lists in Cars

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Figure 1. Driving simulator with head-up (HUD) and headdown (HDD) screen positions indicated. A jog dial controller is mounted to the steering wheel.

It has been established that head-down displays (HDDs), such as those commonly placed in the dashboard of commercial automobiles, negatively affect drivers' visual attention [1]. This problem can be exacerbated when screens are "busy" with graphics or rich information. In this paper, which is an extension of a user-preference study [23], we present the results of a driving simulator experiment where we examined two potential alternatives to HDDs for presenting textual lists. Subjects conducted a series of street name finding tasks using each of three system variants: one with a head-down display (HDD), one with a head-up display (HUD), and one with only an auditory display. We found that the auditory display had the least impact on driving performance and mental load, but at the expense of task completion efficiency. The HUD variant had a low impact on mental load and scored highest in user satisfaction, and therefore appears to be the most viable target for future study.