The red flag means that all competition must stop. This not only includes the drivers on the race track but also the pit crews. If the crew is working on repairing a car in the garage area then they too must stop work when the red flag is displayed.

The red flag is commonly seen during a rain delay or when the track is blocked due to emergency vehicles or a particularly bad accident.

A red flag is always followed by a few yellow flag laps which allow the drivers a chance to warm up their engines and pit if they need to.

The black flag is officially called "the consultation flag." It means that the driver who receives it must pit to respond to a NASCAR concern.

Frequently the black flag is given to a driver who breaks a rule of some type such as breaking the speed limit on pit road. It can also be given to a driver who's car is smoking, dropping pieces on the race track (or in danger of doing so) or a driver who is not maintaining the minimum safe speed on the race track.

A driver receiving a black flag must pit within five laps.

If a driver does not pit within five laps of receiving a black flag they will be shown a black flag with a white 'X' on it.

This flag tells the driver that they are no longer being scored by NASCAR and have effectively been disqualified from the race until they obey the previous black flag and pit.

This is the "courtesy" flag or the "move over" flag. It is the only flag that is optional. A driver may, at his discretion, ignore this flag.

It is displayed to a car (or group of cars) to let them know that the leaders are coming up behind them and that should be courteous and move over to let the leaders race.