The chequered flag has become so well recognized that it is often used to indicate the conclusion of many things unrelated to auto racing. For example, some software installation programs display a chequered flag to indicate that a computer program has been installed successfully. Chequered flags were also posted at each corner of the end zones in the original Yankee Stadium when the facility was used by the New York Giants of the National Football League from 1956 through 1973."
“The Origin of the Checker Flag - A Search for Racing’s Holy Grail”, by Fred Egloff, International Motor Racing Research Center 2006, which takes the origin back to Glidden Tours, a type of road rally where checking stations were identified by the chequered flag. In the same year, a chequered flag was photographed at the finish line of a Vanderbilt Cup Race in New York.
"As Louis Wagner was about to win the contest, starter Fred Wagner waved what is believed to be the first checkered flag used to signify the finish of an auto race. Standing on the railing above the flag, Willie K saluted the victor. The winning Darracq averaged 62.7 mph over the 297.1-mile race. Lancia’s F.I.AT. finished second, only three minutes and 18 seconds behind, followed 16 seconds later by Arthur Duray’s Lorraine-Dietrich."