The materials used for traffic signs should comply with relevant national standards. Commonly used materials include aluminum plates, plastic plates, and steel plates. The reflectivity of the signs should also meet relevant national standards to ensure their effectiveness in darkness or low-light conditions.
The colors and text on the signs should comply with relevant national standards. Generally, the colors of the signs should be clearly distinguishable, and the text should be concise and clear. For example, red background with white text indicates prohibition, blue background with white text indicates instruction signs, yellow background with black text indicates warning signs, and green background with white text indicates directional signs, etc.