Key takeaways
- Under the FIA's Appendix H, a single waved yellow means slow down, no overtaking, hazard nearby; double waved yellows mean slow significantly and be ready to stop.
- A red flag stops the session: cars slow down, may not overtake and stop at the red flag line.
- A blue flag warns a driver they are about to be overtaken; in a race, a lapped car must let the faster car through at the first opportunity.
- Black flags are shown with a car number: plain black means come into the pits, black with an orange disc means a dangerous mechanical problem, and black-and-white diagonal is a conduct warning.
- In FIA racing a white flag means a much slower vehicle ahead; in NASCAR and IndyCar it means the final lap.
Flags are how race control talks to drivers. The FIA sets out its flag signals in Appendix H to the International Sporting Code, its recommendations for supervising the track; this guide follows the 2026 edition. American series such as NASCAR and IndyCar use some flags differently, and those differences are noted below.
Flags shown by the Clerk of the Course
These are shown at the start line:
| Flag | Meaning |
|---|---|
| Red | The session or race is stopped. All cars slow down immediately; no overtaking |
| Black and white chequered | End of the practice session or race |
| Black, with the car's number | Stop at your pit on the next approach to the pit entry |
| Black with an orange disc, with the car's number | Your car has a mechanical problem likely to endanger you or others; stop at your pit next lap |
| Black and white, divided diagonally, with the car's number | Warning for unsportsmanlike behaviour, or for an action that may bring a penalty if repeated |
Appendix H adds procedure. Under a red flag in a race, cars proceed slowly to the red flag line, a 20 cm painted line across the track, and stop in order until told whether the race will resume. Speeding is pointless, the appendix notes, because the classification or restart order is taken from a point before the red flag and the pit exit is closed. It adds that a lap completed after the red flag is first shown is not a valid lap time. The plain black flag is shown for no more than four consecutive laps if a driver fails to respond, and the decision to show it rests with the stewards.
Flags at the marshal posts
| Flag | Meaning |
|---|---|
| Single waved yellow | Reduce speed, do not overtake, be ready to change direction: a hazard beside or partly on the track |
| Double waved yellow | Reduce speed significantly, do not overtake, be ready to change direction or stop: the track is wholly or partly blocked, or marshals are working |
| Yellow with red stripes | Loss of grip ahead from oil or water, shown motionless |
| Light blue | A faster car is about to overtake you |
| White | A much slower vehicle on this section of track |
| Green | Track clear; also signals the end of a yellow-flag zone |
| Purple with a white "60" ("Code 60") | A 60 km/h speed limit on the full course |
Appendix H is specific about what slowing down means under yellow: it must be evident that the driver has braked earlier and/or noticeably reduced speed in that sector.
Full-course neutralisations
When the whole track must be slowed, Appendix H describes several signals:
- a single yellow flag with a board reading FCY, for a full course yellow;
- a single yellow flag with a board reading VSC, for a virtual safety car, a variable speed limit on the full course;
- waved yellow flags and "SC" boards at every marshal post, with orange lights at the line, when a physical safety car is deployed;
- the Code 60 flag, with a 60 km/h limit, followed when it ends by a waved green flag, after which overtaking is allowed again.
In each case, double waved yellows may continue at the post before the incident.
The safety car explained covers how Formula 1 runs its safety car and virtual safety car.
The blue flag in detail
The light blue flag means different things in different sessions. A stationary blue warns a driver leaving the pits of traffic approaching. In practice, a waved blue means a faster car is close behind and about to overtake. In the race, it is normally shown to a car about to be lapped, if the driver does not seem to be using the mirrors, and that driver must let the following car pass at the earliest opportunity.
Where American racing differs
Wikipedia's article on racing flags notes some important differences:
- White flag. In FIA-sanctioned racing it means a slow vehicle ahead; in NASCAR and IndyCar, a waved white flag at the starter's stand marks the final lap.
- Yellow. In NASCAR and IndyCar ovals, a single yellow waved from the starter's stand puts the whole race under caution.
- Green and yellow together. In NASCAR, both waved at once mean the race is starting or restarting under caution with laps counting.
Flags can shape strategy as well as safety; the safety car explained covers how a neutralisation changes the cost of a pit stop. Wet-weather racing covers the yellow-and-red "slippery" flag in context.
In Car Racing - Pro Career Racer, one of our sports career games, cautions and safety periods are among the race events that change which strategy is right; the game guide explains how.
Good to know
Frequently asked questions
What is the difference between a single and a double yellow flag?
What does a blue flag mean?
What does a black flag with an orange disc mean?
Does the white flag mean last lap?
Sources
- Appendix H: Recommendations for the supervision of the road and emergency services, 2026 (opens in a new tab)Fédération Internationale de l'Automobile — accessed
- Racing flags (opens in a new tab)Wikipedia — accessed
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