Premise: The USAC Road Racing Championship was a sports car racing series in the United States held from 1958 until 1962. The series was organized by the United States Auto Club as a fully professional alternative to the Sports Car Club of America's SCCA National Sports Car Championship.
Hypothesis: The USAC Road Racing Championship was a sports car racing series in the United States held from 1958 until 1962. It was discontinued due to motor accidents.