Modern Formula One circuits utilize trackside flashing light panels at regular intervals. These panels provide a clearer signal for conditions such as yellow, green, red, blue, or Safety Car (SC) status than traditional cloth flags.
High-end formula cars feature information displays integrated into the steering wheel. These units are programmed to flash the word "flag" to provide an immediate cockpit warning when a driver enters a sector under a local yellow. This internal display serves as a primary alert, ensuring the driver is aware of hazards even if a trackside marshal post is not immediately in their line of sight.
Electronic lights are also utilized at the end of the pit lane, where blue lights or flags warn drivers of approaching traffic on the main track. Historically, Formula One and other FIA events used the national flag of the host country to signal the start of a race. While starting lights are now the standard electronic device for race starts, the national flag is still used in the event of equipment failure or as a tradition, such as at the 24 Hours of Le Mans.
The integration of lights and flags allows for precise control over the racing environment through several standardized procedures.
When a hazard requires drivers to slow down but does not warrant a physical safety car, officials may implement the Virtual Safety Car (VSC). During a VSC period, all trackside light panels display the letters "VSC" surrounded by a flashing yellow border, and all flag points display a "VSC board." Drivers must reduce speed and remain above a minimum time set by officials in each marshalling sector. Teams are notified via the official messaging system 10 to 15 seconds before the procedure ends and green flags are waved.
In the FIA World Endurance Championship, a similar "Full-Course Yellow" (FCY) is used. Under FCY, all flag points display an "FCY board" and cars must maintain a speed of 80 km/h (50 mph).
When a physical safety car is deployed, marshal stations display a white "SC board" with black lettering, accompanied by a waved yellow flag. This indicates that overtaking is strictly forbidden across the entire circuit. Once the safety car returns to the pits, a green flag and green lights at the start line signal the resumption of the race.
A solid red flag or red light indicates that conditions are too dangerous to continue the session, often due to a blocked track, serious accident, or extreme weather. Drivers are typically directed to proceed to the pit road. During these periods, repair work on the cars is generally prohibited.
Officials use specific flags and light signals to communicate with individual drivers regarding their conduct or the state of their vehicle.
Black Flag: Summons a driver to the pits and, in FIA-permitted series, indicates immediate disqualification. This may be for rules violations or failing to maintain a minimum speed. In 1969, Al Pease became the only driver disqualified from a Formula One race for driving too slowly.
Black Flag with Orange Circle ("Meatball"): Indicates a car has serious mechanical problems or loose bodywork that poses a risk to others, requiring the driver to pit for repairs.
Per-bend Black-White Flag: A diagonally divided black-and-white flag serves as a warning for unsportsmanlike conduct. Charles Leclerc was shown this flag during the 2019 Italian Grand Prix while defending against Lewis Hamilton. It is also used to warn drivers for exceeding track limits, as seen in the 2023 Austrian Grand Prix where multiple drivers received the flag on their third infringement.
Blue Flag: Informs a driver that a faster car is approaching. In Formula One, ignoring three waved blue flags while being lapped results in a drive-through penalty.
Red and Yellow Striped Flag: A stationary flag indicating that track surface conditions have changed, often due to oil, coolant, or water.
White Flag: In Formula One, this is waved on the pit straight at the end of Friday and Saturday free practice to indicate drivers are performing practice starts. In other FIA championships, it warns of a slow-moving official vehicle or a competitor moving at reduced speed.
Chequered Flag: Signifies the end of a session or race. The earliest photographic record of its use to end a race is from the 1906 Vanderbilt Cup.
The transition to electronic light panels and cockpit displays addresses the limitations of manual flagging. On winding road courses, marshals provide the first indication of local hazards. The danger of disregarding these signals was demonstrated during a 1991 CART race in Detroit, where Michael Andretti and his father Mario both crashed into a recovery scene after failing to heed yellow flags. Modern electronic systems minimize these risks by providing redundant, high-visibility warnings directly to the driver.