Enhanced performance for in-vehicle display placed around back mirror by means of tactile warning

In-vehicle displays have been found more effective in terms of reaction time, accuracy and subjective visibility rating when the size of such displays was moderate and placed around a steering wheel. To date, however, little data has been reported on the safety and efficiency of replacing side mirrors with in-vehicle displays placed around a back or room mirror. Although back mirror displays save space for installing other display features, it is expected that they would be inferior to in-vehicle displays placed around side mirrors, around the driver's center position, or around a steering wheel in accuracy and reaction time, because back mirror displays require drivers to execute more vertical eye movement than other in-vehicle displays or side mirrors, and eventually the perceptual and recognition time of hazard becomes longer. The primary purpose of this study was to improve the reaction time and accuracy of in-vehicle displays placed around a back mirror with the support of a tactile warning system. First, participants were instructed to engage in a primary, simulated driving task. Simultaneously with the primary task, participants were required to undertake a secondary, discrimination task. The secondary task involved the discrimination of a pre-specified vehicle displayed on either a side mirror or an in-vehicle liquid crystal display (LCD) placed around a back mirror or steering wheel. Second, reaction time and accuracy of in-vehicle displays placed around a back mirror were examined to determine whether they could be improved with the addition of a tactile warning to the displays. Participants were directed to carry out a driving task (run a straight second lane of three-lane highway) similar to that performed in the first experiment. As expected, in-vehicle displays placed around a back mirror produced inferior accuracy as compared to in-vehicle displays placed around a steering wheel. The tactile warning effectively compensated for the shortcomings of the 4.3-in. in-vehicle displays placed around a back mirror, and it further improved both reaction time and accuracy.