Complex sentence: CART scheduled what was billed as a "Special Qualifying Session" for the U.S.500 on the weekend of May 11--12,1996, which directly conflicted with the first weekend of qualifying for the Indianapolis 500.
Split into simpler sentences: CART scheduled what was billed as a "Special Qualifying Session" for the U.S.500 on the weekend of May 11--12,1996. Qualifying directly conflicted with the first weekend of qualifying for the Indianapolis 500.