This report presents a human factors study that was conducted to seek ways to assist elder drivers’ understanding of dynamic message sign (DMS) messages. The study employed a computer based questionnaire survey and a driving simulation experiment with a goal to measure drivers’ preferences and responses to various DMS displays and formats. The results are included in this report. While the age of the subjects studied ranged between 20 and 94, results for drivers over 60 were of special concern. The survey assessed drivers’ preferences toward different types of graphics, use of graphics in messages, colour of the message, colour of the graphic, message flashing, animation, text alignment, abbreviations, shadowing, and wording sequence. Survey results indicated that drivers preferred text only messages compared with graphic-aided messages, and also preferred animated graphics over stationary ones. Subjects differed on their preferences toward colour, however. A driving simulation experiment was conducted to measure subjects’ responses to DMS displays in different colours and graphical formats, similar to those shown in the survey to provide a comparison. Results from the driving simulation experiment showed that drivers responded faster to amber-coloured messages and graphic-aided messages. Older drivers responded slower and less accurately than younger drivers, but their response time and accuracy were improved with the use of graphics in the DMS messages. Correlations and discrepancies between the results of the survey and simulation are also discussed. (Author/publisher)
Abstract