Evaluation of medium range 'advance information' in route-guidance displays for use in vehicles

This work compares methods of presenting route guidance information to drivers. Field trials were conducted, with each of sixteen subjects undertaking two driving conditions, each on a different route, one with visual guidance information only and the other with both visual and auditory information. Half the subjects immediately after completing a maneuver were briefly given advance information messages warning them of the distance to, and nature of the next turn from the road ahead. Perceived mental workload, frequency and duration of glances to the display, and subjective views were measured. Presentation of visual and auditory information was the preferred mode, reducing both mental workload and time spent looking at the display. Advance information helped in the navigation task, but did not reduce the glance frequency or duration to the guidance display.