Presence and Quality of Navigational Landmarks: Effect on Driver Performance and Implications for Design.

Although current in-vehicle navigation systems predominately use distance-to-turn information to enable a driver to locate a forthcoming maneuver, the incorporation of landmarks as key navigation cues could be an improvement. This study investigates the impact of landmark information of varying quality within drivers' navigation instructions on driving and navigation performance. An empirical field trial in a real traffic environment was undertaken with 48 participants in order to assess the effect of landmark quality on driver behavior when navigating an unfamiliar, complex, urban route. Four main constructs were assumed to be key determinants of the effectiveness of a landmark as a navigation clue: its visibility to an approaching driver, its familiarity, its uniqueness in terms of being dissimilar to other nearby objects, and the usefulness of its location. Results showed that the use of good landmarks as key verbal navigation cues improved navigation performance, driving performance and driver confidence immediately preceding a turn. The use of distance information to locate a turn resulted in significantly more glances to the in-vehicle display. The use of poor landmarks resulted in worse driver performance than that obtained using distance-to-turn to locate forthcoming maneuvers.