At one point they commented on the radio that about 28 of 89 laps of the race being under caution. The cleanup of debris needs to be done after a wreck but all of the yellows last almost that long. Sitting there I couldn't help but put the blame on a combination of the double file restarts and Firestone.
From the start one of the drivers' complaints was restarting on the outside with marbles. In response the series began sending sweepers and blowers out on every caution to make that outside lane clearer. That means even a simple spin with no debris causes a long delay for those slow sweepers to make a lap.
They wouldn't have to do that if Firestone wasn't making such soft, and grippy and fast tires that shaved off so many marbles.
The trade off appears to be, higher racing speeds with the racier tires and the closer racing competition by bunching up for double file restarts but longer caution periods while the marbles are swept up by those slow sweepers and blowers because the outside lane needs to be cleared.
After the season I think they should evaluate not how many yellows there are but how much of the racing laps they eat up to clear the marbles. Then decide if the clean up for the double file restarts makes those restarts worth the racing time lost or if Firestone should make more of an effort to have tires that give off less rubber that needs to be swept.