Meaning of Racing Flags

When there is a need to infirm racers about conditions on the track and to convey messages to them, starters, grand marshal and track marshals of race use racing flags. These flags are used in auto racing and similar motorsports. There is no universal set of race flags far all motorsports but some series have standardized sets of flags with strictly defined meanings. Most widely used set of flags outside of the North America are FIA-sanctioned championship flags and they are used in Formula 1, the FIA World Endurance Championship and WTCC championships. Some of them are used in NASCAR and IndyCar and they can but not have to have the same meaning:

• Green flag: Start, end of hazard, or restart of the race. It can also be on the entrance to the pits to indicate that the pits are open and signal the end of a local yellow-flag zone.
• Yellow flag: Local caution or full-course caution. It requires of drivers to slow down due to a hazard on the track. Single waved flag signals a hazard that is located only on the racing surface itself while two flags waved simultaneously mean a hazard that wholly or partly blocks the track.

• Flag with yellow and red vertical stripes: Debris/oil/slippery course. If it stands still it signals dangerous substance on the track but if it is rocked back and forth, but without waving, it signals small anima on the track.
• Red flag with yellow diagonal cross: Pit lane closed (Only in NASCAR and IndyCar). The cars are directed to proceed to pit road, or to stop at a specific spot. Sometimes repair work in the pits or garage area is forbidden under the red flag.
• White flag: Slow vehicle on track (FIA) or Final lap (NASCAR)
• White flag with red cross: Final lap (FOA) or Ambulance on course (IndyCar)
• Black flag: disqualification or penalty. Summons a driver to the pits for disobeying the rules or when a car is suffering a dangerous mechanical failure.
• Black flag with orange circle: dangerous mechanical problem on a certain car and car must return to its pit (FIA only)
• Flag divided diagonally -upper left part black/lower right part white: Unsportsmanlike conducts (FIA only) such are intentionally driving another car off the course or initiating of an altercation with another driver.
• Black flag with white diagonal cross: Driver is no longer scored (Only in NASCAR and IndyCar) because he or she decided to ignore the other black flags for an extended period of time. Car stays not scored until it answers the black flag by pitting.
• Blue flag: Faster car approaching (FIA), Local caution/slow vehicle on track (NASCAR)
• Blue flag with yellow diagonal line from upper right to lower left: Faster car approaching (NASCAR). Driver should move aside to allow one or more faster cars to pass.
• Checkered black and white flag: Session finished. Leader of the race is a winner and drivers are required to slow to a safe speed after they cross the finish line.