What were the IRLs predecessors?
Indy car racing has of course been around much longer than the IRL itself has been. The IRL traces its origins back through the races sanctioned by CART prior from 1981-1995, then to the USAC sanction which ran from 1956-1980, and then back to the AAA sanction which ran from the first Indianapolis 500 in 1911 through 1955.