After the invention of the automobile, more and more drivers driving at night, reflective traffic signs become problems that should be solved. Therefore，In 1920, people affected by cat eyes in the night lights and can emit light of the impact of the invention of opal to make reflective signs, then make use of opal reflective traffic signs, the retro reflective poor, needs to be improved. By 1930, with the progress of science and technology, people began to make signs reflective material with a relatively small glass beads, and come to realize the importance of reflective strength and reflective products fastness, such as visibility distance, rain resist etc.
