Fontana superspeedway off IndyCar schedule in 2016

The 2-mile superspeedway had been in an ongoing struggle to secure a date and broadcast slot that translated into a strong audience, both on TV and in the grandstands.

Last year's season-finale at the venue drew poor TV ratings because the 7:20pm start time translated into a 10:20pm start time for viewers on the east coast of the US.

This year, the race was switched to a more TV-friendly afternoon start, but the intense mid-summer heat contributed to a fan turnout that was estimated to be as low as 4000.

"There was a tremendous amount of effort put forth to keep Auto Club Speedway on the calendar," said Mark Miles, CEO of IndyCar parent company Hulman & Co.

"In the end, we could not identify a compromise for 2016 that was amicable for both parties.

"We're thankful to (Auto Club Speedway President) Dave Allen for his efforts in these negotiations.

"We mutually agreed that our inability to identify a date for next year doesn't preclude us revisiting these conversations in the future."

Fontana's absence from the schedule will not necessarily translate into a reduction of the overall number of ovals, with speculation increasingly mounting that the series will soon confirm a return to Phoenix.