NASCAR Basics: Flags

Originally published at Meanwhile... on March 12, 2008

In NASCAR posts I'll sometimes talk about the race being red-flagged and drivers being black-flagged or races ending with a green/white/checkered finish. You might not have any idea what I'm talking about, so here's a brief primer on flags, eight different ones...

NASCAR races get off to a rolling start with drivers beginning with a couple or a few laps under yellow.  These laps don't actually count, but once the pace car drops onto pit road and the green flag waves, all laps, green, yellow and white, do count in the scheduled distance of a race.

Green

When the green flag waves, at the beginning of the race and after a caution period, the race is on, boys! Boogity-boogity-boogity! Put the hammer down!

Yellow

Yellow means caution. There is a hazard on the track -- an accident, debris, light rain, etc. -- something that makes racing unsafe. The pace car will pull back on the track and drivers must fall in line behind it. Yellow periods usually last at least three laps, allowing drivers enough time to pit and fall back in line behind the pace car. On the last yellow flag lap, the pace car will turn off its roof lights to alert the drivers that racing is about to resume.

The Lucky Dog -- Years ago, when a yellow flew, drivers would race back to the start/finish line for position. Drivers a lap down would race the leader back to the line to get their lap back. Accidents ensued. With the advent of electronic scoring, NASCAR was able to freeze the field when the caution came out. The drivers now slow down immediately and maintain their positions in the field until they pit. Now, whenever a yellow flag flies, the first driver a lap down is the Lucky Dog. He gets his lap back. He must pass the pace car and circle around until he comes to the back of the pack.

Red

All competition must stop. Red flags are typically seen during rain delays and when the track is blocked due to a particularly bad accident. Drivers stop behind the pace car at a point on the track where they won't be in the way or on pit road. A red flag is always followed by a few yellow flag laps to allow the drivers to warm up their engines and tires or make a pit stop.

Additionally, all work in the pits and garage must stop.  Crews can look the car over and lay out all the tools and parts needed, but work can't resume until the red flag is lifted.

If an accident happens near the end of a race, NASCAR will wave the red flag instead of allowing the race to continue and end under caution (yellow). Track workers will cleanup the track while the drivers are stopped. Drivers will then make the yellow flag laps that follow a red, but the race will go into overtime -- a green/white/checkered finish -- a two-lap shootout. When the green flag waves, the racing will resume. The next time by the start/finish line, the white flag will wave. The next time by, the checkered flag ends the race. If a yellow comes during the green/white/checkered finish, the field is frozen and the race is over then and there. 

2010 Update: NASCAR changed the rules for green/white/checkered finishes. No longer does a yellow flag end the race. As long as the leader does not take the white flag, up to three attempts can be made to end the race under green. If the leader does take the white flag and a yellow flag follows, the field is frozen and the race is over.

Black

Black is not good. A black flag is a "consultation" flag. It means that NASCAR officials need to consult with the driver immediately. You can be black-flagged for breaking a rule such a speeding on pit road or failing to maintain the minimum speed limit. You can also be black-flagged if your car appears to be unsafe, i.e., pieces are falling off of it or it's smoking or leaking fluid on the track. Drivers who are black-flagged must pit within five laps.

Black with a white X

A driver who has been black-flagged and doesn't pit within five laps is shown the black flag with the white X. This means that they are no longer being scored by NASCAR (their laps aren't being counted) until they obey the black flag and return to the pits.

Blue with an orange diagonal stripe

This is the "courtesy" flag. It tells a driver (or a group of drivers) that the leaders are coming up. Please be courteous and get out of the way. The courtesy flag is the only flag that a driver may ignore at his own discretion.

White

The white flag flies only once during a race, signaling one lap to go in the race. Again, if a yellow flag flies on the white flag lap, the field is frozen and the race is over.

Checkered

This is simple enough. The first one to the checkered flag wins the race.