Auto racing (also known as automobile racing, autosport or motorsport) is a sport involving racing automobiles. Motor racing or motorsport may also mean motorcycle racing, and it can further include motorboat racing and air racing. It is one of the world’s most popular spectator sports and perhaps the most thoroughly commercialized.
Use of flags
In open-wheel, stock-car and other types of circuit auto races, flags are displayed to indicate the general status of a race and to communicate instructions to competitors in a race. While the flags have changed from the first years (e.g. red used to start a race), these are generally accepted for today.