Black Racing Flags

In FIA International-permitted series (Grand Prix), the black flag means an immediate disqualification for the driver involved. The car number of the summoned driver is displayed on the finish line. Some sanctioning bodies wave the black flag at all observation posts simultaneously to order all drivers to clear the track after the starter waves the red flag, often in the case of a serious accident.

When the black flag is used for disciplinary reasons in most races in North America, a driver is required to return to pit lane for at minimum a drive-through penalty. A driver may be black-flagged for failing to maintain a reasonable minimum speed, even if no apparent damage or mechanical failure is present. In almost all cases, the team is given a chance to make repairs to the car and get it up to an acceptable condition. If the driver still cannot maintain minimum speed in relation to the leaders after repairs, the driver may be required to park for the remainder of the race. For example, NASCAR requires that a driver run at or above 115 percent of the fastest lap time by any driver in the final practice. (This can be converted to an average speed-limit based on the length of the course, which for oval tracks will be close to the actual speed limit at any given time.) IndyCar has a 105 percent rule, most notably used when officials parked Jean Alesi and Simona de Silvestro during the 2012 Indianapolis 500.

In the case of snowmobile racing, the black flag comes in three stages to disqualification; the first flag is a warning to a racer, the second flag is a one-lap penalty, and the third is disqualification. In order for a snowmobile racer to receive a black flag, the racer must make contact with intent to inconvenience another racer.

During the Coke Zero Suzuka 8 Hours (FIM World Endurance Championship), a black flag waved from the starter's stand designates the start of the race. This race flag, which is black, carries the race sponsor's name on it. Wikipedia