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• Development of Human Factors Guidelines for Advanced Traveler Information Systems and Commercial Vehicle Operations: Comparable Systems Analysis

Development of Human Factors Guidelines for Advanced Traveler Information Systems and Commercial Vehicle Operations: Comparable Systems Analysis

Usability

Usability of the TravTek system was addressed in a series of questionnaire items as depicted in figure 17. In general, the usability of the system as represented by ease of learning, ease of understanding, and way finding were rated quite positively. In addition, other factors related to usability, including driving interference and proper function, were also positively rated.

Figures 18, 19, and 20 highlight differences in trip planning time, travel time, and number of wrong turns while navigating for the Orlando Test Network Study (Inman, Fleischman, Dingus, and Lee, in press). Six conditions were utilized for this study, including turn–by–turn guidance and route map with and without voice, voice alone, and a control condition consisting of a paper map. Trip planning time and travel times were higher for the paper map condition when compared to any of the TravTek conditions.

Note, however, as shown in figure 20, that more turning errors occurred for the route map condition without voice as compared to any other condition. In contrast, the route map with voice had the lowest turn error rate, but it was not a great deal lower than the voice alone or guidance screen without voice conditions.