The Grand Prix Americas from Miami produced a national rating of 1.4 which equates to a viewing audience of 1.48 million households in the US. The race was shown live in 39 percent of US markets and broadcast on tape-delay in the remaining regions.
The figure eclipsed the previous best rating at the Miller Lite 250, held on June 2, which was watched by 1.26 million households.
This is the first year that CBS has screened live CART coverage, covering seven races over the course of the season. The remaining three races of the season will be broadcast on cable network the Speed Channel.
CART's broadcast strategy has come under increasing pressure following the huge growth in ratings for rival motor sports franchise NASCAR in recent years.
The final CART broadcast of the season on CBS drew the franchise's largest television audience of the year.
