Signals, Signs and Pavement Markings · Traffic Sign Colors
Red: Stop, yield, or do what is posted on the sign.

Red: Stop, yield, or do what is posted on the sign.
Green: Indicated movements permitted, direction guidance.
Blue: Motorist services guidance.
Yellow: General warning or caution.
Black: Regulation.
White: Regulation.
Orange: Construction and maintenance warning.
Orange (Retroreflective): Used on various types of signs.
Brown: Public recreation and scenic guidance.
Learn it with your state's rules
DMV One Way teaches the whole handbook slide by slide and checks it with practice questions.