A82 Road users with hearing loss and evaluation of tactile support systems

Abstract

Abstract Background Research regarding the effect of Hearing loss (HL) on traffic safety and mobility is limited and the empirical findings are somewhat inconsistent. HL is one of the most frequent sensory deficit in humans, which may affect behavior in traffic situations and might reduce traffic safety. The prevalence of age-related HL in Europe is roughly 30% for men and 20% for women at the age of 70 years, and 55% for men and 45% for women at the age of 80 years. The prevalence of age-related HL is increasing, and as a consequence the number of road users with HL will also increase. Methods To investigate traffic safety and mobility for individuals with HL three studies have been conducted; 1) a questionnaire survey, 2) a driving simulator study, 3) a field study. Results The effects of HL on traffic safety and mobility are small, often bound to workload condition, however quite consistent. Differences in transportation habits related to HL include less likelihood of having a driving license and a higher valuing of written information, with the latter sometimes prioritized before time and safety issues. Respondents with higher degree of HL were less concerned about the effect of HL, indicating that they might be using compensatory strategies. Differences related to HL in driving behavior were bound to driving condition and occurred when complexity of driving task increased. There was also an effect of HL on visual behavior, suggesting that drivers with HL have a more active visual behavior with more frequent glances in the rear view mirror and a general scanning of the environment before looking away from road. Tactile signal in the driver seat was found useful in both experimental studies, both for calling for driver attention and to facilitate navigation with a GPS. Of high relevance for traffic safety and regardless of hearing status, the tactile support lead to higher satisfaction with the navigation system, less time spent to look at the navigation display, and more focus on road and better driving performance. Conclusions There are effects of HL on both traffic safety and mobility, consistently pointing towards a generally more cautious driving behavior, suggesting a difference in experienced safety. The appearance of compensatory strategies associated with HL is bound to driving condition and include driving at lower speeds, more comprehensive visual search behavior and less engagement in distracting activities. By adding a tactile modality, some driver assistance systems can be made accessible also for drivers with HL.