It was the first post-World War II sports car series organized in the United States.
Until 1953, a single championship was awarded, with points paid based on finishing position within each class.
Following the 1962 season, the professional USAC Road Racing Championship collapsed, leaving many competitors looking for a series.
Top drivers from the regions were invited to the American Road Race of Champions (today known as the National Championship Runoffs) at the end of the season.
For 1966, national championships were awarded only to winners at the ARRC, a system which continues today as the Runoffs has become the most prestigious road racing event for club racers.