How does the ‘green-white-checkered’ rule work in NASCAR?

NASCAR has been using the ‘green-white-checkered’ rule for over two decades. The procedure is used to safely restart the race after a caution period ahead of the final two laps.

NASCAR first introduced the rule in the National Series in 2004. The procedure was created to make sure races ended under the checkered flag after an incident. Initially, the overtime run under the rule was restricted to just one 2-lap attempt. However, the rule was amended in 2010, allowing to run unlimited attempts after the scheduled distance of the race.

The 'green-white-checkered’ rule was first used in the Craftsman Truck Series. Under unfavorable circumstances, if a race reached the scheduled distance under a caution flag, the sanctioning body could then allow for an overtime run.

This would allow the remaining drivers to have a fair fight to finish with two additional laps after the green flag is waved. The rule also favors NASCAR fans, as a finish under caution robs the excitement provided by racing hard until the end.

Despite the rule, there have been several instances where a race has ended under the caution flag. The most recent example was the 2024 Daytona 500 race where the caution flag was waved on the last lap under the white flag condition.

Here's a look at what each flag used under the ‘green-white-checkered’ rule means:

#1. Yellow flag

A yellow flag is used to signal a caution period during a race in the event of a crash. This is generally used to help authorities clear the track of any debris or fluids from the crashed vehicle/s and repair any damage to the safety rails.

The caution period can last multiple laps, allowing drivers to continue racing behind the safety car with reduced speed. If the yellow flag is waved before the final lap begins, the race will automatically go into overtime.

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#2. Green flag

Once the racetrack is cleared and authorities deem it race-worthy, a green flag is waved to restart the race. This is done only after the safety car is called in. Under the rule, NASCAR allows the race to run at full speed for two laps.

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#3. White flag

Just after a lap under the green flag, authorities wave the white flag signaling the beginning of the last lap of the race. Once waved, the race can only continue for one final lap. This also means that any accident under the white flag doesn't invoke a caution period.

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#4. Checkered flag

The iconic black-and-white checkered flag signals the end of the race. Once waved, all drivers have one last chance to push to the finish line, thereby finishing the race under normal circumstances. While the result generally stays unaltered after the checkered flag, the sanctioning body has the authority to make changes, should there be any discrepancies.

A recent example was the race at Richmond, where Austin Dillon's playoffs status was revoked for unsportsmanlike conduct against fellow racers Joey Logano and Denny Hamlin on the last lap.