Kammala jumla mai zuwa: Lokacin da American Automobile Association (AAA) ya janye daga tseren motoci bayan kakar 1955, yana mai cewa bala'in Le Mans da mutuwar Bill Vukovich a
Indianapolis a matsayin abubuwan da ke ba da gudummawa, duka SCCA da NASCAR an ambace su a matsayin magaji mai yuwuwa. A ƙarshe, mai mallakar Indianapolis Motor Speedway Tony Hulman ne ya kafa USAC. Ya zama mai yanke hukunci game da dokoki, ƙirar mota, da sauran batutuwa don abin da ya kira gasar tseren motoci, mafi girman matakin tseren USAC. Na ɗan lokaci akwai jerin keɓaɓɓun ƙayyadaddun bayanai don motocin zakarun da aka tsara don yin aiki a kan ƙazanta, maimakon a shimfiɗa, hanyoyi.