The object of this contract was to identify problems with the visibility of changeable message signs (CMSs), particularly for older drivers, and to develop design guidelines and operational recommendations to ensure adequate conspicuity and legibility of in-service CMSs. This project was divided into three main sections: a field survey of in-use CMSs, a series of laboratory experiments and static field studies, and a partially controlled dynamic field study. The research was designed to optimize CMS components, including the character variables (font, width-to-height ratio, color, and contrast orientation) and the message variables (inter-letter, inter-word, and inter-line spacing).
Changeable message signs (CMS's) have been used on major highways since the 1970's. However, unlike other traffic control devices, there are no nation...
Research conducted recently for the United States Sign Council Foundation found no consensus in the researchliterature or the practices of the commerc...
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United States Department of Transportation
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