The purpose of this research program was to understand, and where possible, ameliorate the effects of visual aging on the visibility of symbolic highway signs. Three studies were conducted, the specific objectives of which were to: (1) evaluate if, compared to standard text highway signs, symbolic highway signs offer older drivers significant advantages in visibility under day and/or dusk lighting conditions (Study 1); (2) determine the extent to which the visibility of symbolic highway signs can be increased among young, middle-aged and elderly drivers (Study 2); (3) assess the capacity of image-processing techniques to represent the visibility of symbolic signs for young, middle-aged and elderly drivers (Study 3); and (4) estimate the capacity of static acuity and contrast sensitivity measures to predict the visibility of highway signs among drivers of different ages (Studies 1, 2, and 3). This report contains descriptions of the study methods, study results, and discussions of the findings. (A)
Abstract