Abstract: In order to help drivers win more operating time and improve traffic safety , the legibility of traffic signs was researched. LED active luminous guide signs designed to be trialed on the middle ring road of Taiyuan city and reflective film signs of the same specification were taken as research objects. Legibility researches were made both on LED active luminous traffic signs and reflective film signs under different experiment conditions of the day and night. The results show that the legibility of traffic signs which recognized by drivers is related to their environment and condition,and that there is a little difference between the legibility of LED active luminous traffic signs in day and that at night , but it is much better than the legibility of reflective film signs at night, the former is greater than the latter by 1.3-1.9 times.

Key words: light emitting diode(LED) , active luminous traffic signs, reflective film signs, legibility distance, influence factor