Yellow vs. Green Flag Pit Stop
At the Indianapolis Motor Speedway, an IndyCar Series car is on pit road for about 38 seconds, including the time the car is stopped and being serviced. However, the driver begins slowing the car on the exit of Turn 3 on the "in lap." After the pit stop, it takes up to the of Turn 4 for the car to return to full racing speed on the "out lap." At the Indianapolis Motor Speedway, a green flag pit stop cost the pitting car about 42 seconds, or roughly one lap, relative to the leader of the race.
Yellow Flag Pit Stop:
Once the yellow flag is out, cars are grouped behind the Pace Car single file for a slower-speed caution lap. Once the pits are open all cars are eligible to pit. Cars enter and leave pit road at an equal, controlled speed for the "in lap" and placed in order of how they exit pit road.
Once the cars are grouped behind the Pace Car and the leader of the race is established, all cars between the Pace Car and the race leader are waved around the Pace Car to take up their positions at the back of the field and may pit before the restart. This allows lapped cars that did not pit to get one lap back and the race leader to lead the field to the green flag on the restart.
For oval races, entry into the pits under a caution must take place off Turn 4.
Green Flag Pit Stop:
Under green flag conditions, a driver's "in-lap" (the lap before pitting) must be faster than the race pace before heading to pit lane to make up any time that will be lost during the upcoming pit stop.
Once the pit stop is completed the driver has to return to full speed on the track as quickly as possible for the "out lap."
The driver must handle the first laps after a green flag pit stop with care, knowing the new "cold" tires offer less grip.
Cars will indicate their intent to pit by dipping the two left side wheels below the line on the backstretch when racing on ovals. The car will begin its entrance to the pits off the backstretch going into Turn 3.