A field study was conducted to evaluate the use of an additional tactile signal in a navigation system and to examine the effect of hearing loss on driving behavior. 32 participants took part in the study, whereof 16 with normal hearing and 16 with moderate hearing loss.

The participants performed two preprogrammed navigation tasks. In one they received only visual information from the navigation system and in the other there was an additional vibration in the seat to guide the driver in the right direction. Both routes included two levels of driver workload. The order of which the systems were tested as well as the order of workload level was balanced over the participants.

Pretest included hearing screening of normal hearing participants, verbal ability test and KIPS test battery for cognitive performance. During the run an on-road protocol was used to evaluate driving performance. A VBOX was used to measure speed and record the route with a video camera. SMI glasses were used for eye tracking, which means the field of view was recorded with a marker showing where the driver is looking. Predefined targets will be analyzed, e.g. the mirrors and the speedometer. A questionnaire including questions about the experience of the two navigation systems was given to the drivers afterwards.

Analysis continues but preliminary results indicate that hearing loss is associated with lower speed, higher satisfaction with the additional tactile signal and more glances in the rear view mirror.