An investigation was carried out to determine to what extent colour coding of borders on direction signs optimised the detection of local and non-primary destinations. Both categories of destination were either presented together on a combined sign with a black border or appeared on separate signs. In the latter case, signs displaying local destinations were either colour coded with a blue border or the level of colour coding was enhanced by including a blue chevron. The apparatus was designed for constant speed zoom presentation of stimuli. Reaction times, response accuracy and subjective confidence levels were recorded for 10 younger (mean age 22.3 about 2.8 years), 8 middle aged (52.9 by approximately 5.4 Years) and 10 older (73.7 about 6.2 Years) drivers. All age groups responded better to combined sign arrays compared to separated sign arrays unless the level of colour coding for the latter was enhanced, in which case little difference was found between the two types of sign array. These results were, however influenced by the positioning of local destinations which always appeared below non-primary destinations in an array. Removal of this factor resulted in elevated performance levels as the level of colour coding was increased.
Abstract