A little old but the mouse network yielded good ratings for the Detroit doubleheader:
"The second race of IndyCar’s annual Detroit doubleheader had a 0.9 final rating and 1.4 million viewers on ABC last Sunday afternoon, up a tick in ratings and 20% in viewership from last year (0.8, 1.2M) and up 50% and 57%, respectively, from 2014 (0.6, 891K). The previous day’s race had a 0.7 and 1.0 million — up a tick in ratings and 20% in viewership from last year (0.6, 845K) and down a tick and 17%, respectively, from 2014 (0.8, 1.2M)."