我國國道的可變資訊標誌 (VMS) 採用的材料為 LED顯示板，雖有較佳的顯示效果，但易受到外在環境條件干擾，而影響到駕駛的視認性；尤其對高齡者而言，其影響更甚。本研究探討年輕及高齡駕駛者對可變資訊標誌之視認性，採實驗室模擬，研究內容包括： 1. 不同的中文點陣字體於明暗背景下的視認性； 2. 下雨、黃昏色溫、起霧等環境因素對可變資訊標誌的資訊呈現造成視認度的影響； 3. 不同的文字間距及行距造成視認上的影響。由實驗結果得知，對於年輕受測者，中圓及中黑體視認性較佳，而對高齡者而言，中圓及中楷體視認性較佳，適度增加文字間距及行距可提升其視認性，而白色文字背景的視認性高於黑色背景，在所有實驗變項中，兩實驗族群間呈顯著性差異，高齡受測者僅為年輕受測者約二分之一的視認能力。

Variable Message System (VMS) with LED as light source has been widely used on highway throughout Taiwan. Although it can provide better visual display, various design parameters and environments may influence drivers’ recognition of information and therefore, are worth investigations. The research was conducted using lab simulation to see if the drivers could recognize the information displayed on the VMS under various environmental conditions, such as raining, sunset, and fog, etc., as well as with various design parameters, such as Chinese font type, resolution, color of background, and space between texts etc. Both young subjects and the elderly were requested to participate in the test and the differences were compared. The results show that the Chinese font “Zhong-Yuan” and “Zhong-Hei” were more easily recognized by the young subjects while for the elderly it was “Zhong-Yuan” and “Zhong-Kai”. The results also show that larger text spacing or row spacing could enhance the recognition, and the white background was better than the black one. As for the recognition of VMS between two subject groups, significant differences were observed. The size of the information to be well recognized by the elderly are nearly double the size of that for the young subjects.