Different coloured flags are in use from early days of motoracing to communicate with drivers about different conditions on the track, penalty situations and start and end of the race. All marshals at different points around the circuit are issued some of this standard flags to communicate this messages to drivers.
Indicate start or end of the race. Also indicate end of practice and qualifying session. On the end of the race it is shown first to the winner and then to every car that crosses the line after him.
Danger on the track ahead of the given signal. A single waved yellow flag warns drivers to slow down, and two simultaneously waved yellow flags at the same post means that drivers must slow down and be prepared to stop if necessary. During yellow flag period, overtaking is prohibited.
All clear, you can continue with race
Stop of the session.
Indicate that driver that hi is about to be lapped. Driver must left faster car to overtake him. If he doesn’t comply, after 3 blue flags hi risk to be penalized.
Yellow and red striped flag
Slippery track surface, usually because of oil or water.
Black with orange circle flag
Shown together with a car number, it warns a driver that he has a mechanical problem and must return to his pit.
Half black, half white flag
Shown together with a car number, it warns a driver of unsporting behavior. May be followed by a black flag if the driver does not comply with the warning.
Shown together with a car number, it order a driver to return to his pit. Most often is used to signal to the driver that he has been excluded from the race.
Warns racing drivers of a slow moving car on track. Can be ambulance or firefighters.