An Examination of Driver Eye Glance Behavior, Navigational Errors, and Subjective Assessments While Using In-Vehicle Navigational Systems With and Without Landmark Enhancements

This study investigated the effects of three navigation system human-machine interfaces (HMIs) on driver eye-glance behavior, navigational errors, and subjective assessments. Thirty-six drivers drove an unfamiliar 3-segment route in downtown Detroit. HMIs were 2D or 3D (level-of-detail) electronic map display + standard voice prompts, or 3D map-display augmented by photorealistic images + landmark-enhanced voice prompts. Participants drove the same three route segments in order but were assigned a different HMI condition/segment in a 3-period/3-treatment crossover experimental design. Results indicate that drivers’ visual attention using the advanced navigation systems HMIs were within US Department of Transportation recommended visual distraction limits. More turns missed in the first route segment, regardless of HMI, were attributable to greater route complexity and a late-onset voice prompt. Participant’s ratings of HMIs were influenced by the context in which that HMI was used. Acceptability-usefulness ratings were generally positive; negative ratings arose for the three navigation systems from the first route segment. Stress and workload ratings were affected by route segment but not HMI. Ratings on the TLX ‘Frustration’ workload subscale were significantly lower for the enhanced 3D+ navigation system compared to the 2D system, but not significantly different from the 3D system suggesting enhanced voice prompts were beneficial. Participant’s preferred the 2D to 3D map-display (2:1 margin); availability of photorealistic landmark imagery over no imagery (3:1 margin); and enhanced over standard voice prompts (9:1 margin). When presented in a timely fashion, availability of landmark information may be desirable for wayfinding, reduce frustration, or accommodate driver preferences.