The Austin event is one of the six events that were chosen to run the sprint format in 2023 – which features qualifying on Friday, a standalone sprint day on Saturday and then the main grand prix on Sunday.
The sprint format is intended to help bring more excitement to the overall event, with action taking place on all three days – which in theory should bring more weekend fans.
But Circuit of the Americas chairman Epstein has revealed that having a sprint race has not been the success in driving a bigger audience for Saturday.
“It didn't help,” he told selected media including Motorsport.com. “It's a surprise.
“You have to decide at what point are people coming for the event, which I think our fans are coming for the event, as much as they are for the sport. So, I think it still remains to be seen whether the sprint race is something the fans are embracing, or it's more controversial.
“You’ve got people that are proponents of it and advocates, and you have others that say I like it the way it was. It's still an experiment at this point.”
While Epstein acknowledges that the overall ticket sales trend for 2023 may have been impacted by Red Bull and Max Verstappen’s dominance of F1, he thinks that can be ruled out as the factor behind what has happened.
Asked how he could be sure it was the sprint race and not single-team dominance that were a turn off, Epstein said: “You probably can't, but one didn't outweigh the other enough.
“I guess the only way to say it is that when Sunday is still as strong as it was last year, that probably answers the question that you asked.
“Why is Sunday still so strong if it's the Max factor that affects the attendance? I'd say ‘well, I passed that test [in strong Sunday sales] and now I'm saying, part two is Saturday this year was a little bit less than Saturday last year, and yet we have a sprint race this year. So that's the only thing that moved.”
Epstein said he was not sure if the evidence of this year meant Austin would go for a sprint again in 2024.
“We will work with F1 and let them decide what's best, but we're happy for it to rotate around a little,” he said.
