green flag
The green flag tells the drivers to start racing. It is shown at the beginning of the practice session, qualification attempt and race, and whenever a race is restarted after a caution period or red flag period.

yellow flag
This flags warns drivers to drive with caution. Once the yellow flag is displayed, all drivers must immediately reduce speed to a cautious pace and get in a single-file line behind the leader until the green flag is displayed to restart racing. During a qualification attempt, the attempt is halted.

yellow flag with two vertical red stripes
Used only on road courses, to signal that fluid or debris is ahead.

blue flag, diagonal orange stripe
This flag is known as the passing flag. It tells slower drivers who are more than a lap down to show courtesy and let the leaders pass. This is the only flag that drivers may choose to ignore.

black flag
The black flag tells a driver to report to the pits immediately. Normally, this flag is waved at an individual car, either because it has a mechanical problem or has broken a rule. In any case, the driver who receives a black flag must report to the pits.

black flag with white cross
Cars that refuse to acknowledge the black flag are shown this flag. It means that course officials have stopped scoring the car until it returns to the pits for consultation.