The yellow flag is waved as following:
-Before the race, there are three pace laps. The yellow flag is displayed for all of these laps before the green flag waves for the first time all race.
-Whenver a caution occurs, the signifying signal is the yellow flag, which will wave all of those laps. For events the flagman does during a caution restart, see the flagman article.
-If a caution occurs during a practice, the yellow flag is not waved. Cars go to pit road and the red flag is showed during cleanup.