YELLOW STOP SIGN

Historical Background on Yellow STOP Signs:

• In the early 20th century, STOP signs were not standardized and appeared in various colors including white, yellow, and even green in some areas.
• By 1924, the American Association of State Highway Officials (AASHO, now AASHTO) recommended using yellow with black letters for STOP signs, as yellow was considered more visible in low light conditions.
• Yellow STOP signs were standard from the mid-1920s to the early 1950s.