Phoenix represented a mixed bag for NASCAR in the TV Ratings department. The Xfinity Series, featuring their first Dash 4 Cash race of the year, saw a small increase in viewership over 2016. While the 1.76% increase, totaling an estimated 32,000 extra viewers, is a small increase, this is just the second race of the year to see an increase.
The Cup Series, on the other hand, tumbled significantly from 2016. While the race this year did face March Madness head-to-head (which itself is up significantly over 2016 for many games), that competition would not singlehandedly explain the 18.75% decrease from 2016, or the over 20% decrease from the Las Vegas race that aired in 2016 against March Madness.
The alarming stat from Vegas is that consecutive NASCAR Cup Series events have now lost around 1.25 million viewers from 2016. Through the first 4 races, viewership in 2017 is down almost 2.2 million viewers- and this is in spite of the Daytona 500 seeing a gain of over 500,000.