Green means race begins or resumes from another conditional flag.Yellow means racing under caution. Conditions adverse or hazardous.Red means racing has come to a halt. All pit crew and repair work must cease.Black means the ‘consultation flag’. Driver must pit. Usually due to rule violation.Black with White ‘X’ means driver no longer scored for failing to pit under black. Blue With Yellow Stripe means let faster cars by. This one is optional to a degree.White Flag means last lap of the race.Checkered flag means race is over. Winner will be declared.