Austin races against time for planning permission
Construction is scheduled to begin in December, but the local American Statesman newspaper reports that planning authorities have prepared a four-page list of concerns about the proposed project.
The media report said the Texas project is therefore "some distance from satisfying the government bureaucrats" who must agree before the groundbreaking can occur.
"They're getting there," said a county department official, "but they still have a way to go."
If the US grand prix does go ahead as scheduled, promoter Tavo Hellmund is expecting a big flow of Mexican supporters, given the signing of Sergio Perez by Sauber.
"I think it will mean 20,000 (extra) fans for sure," he said. "I think it's really going to create a lot of interest."