State transportation officials are fearful that another congressional stalemate next month could shut down highway and transit construction projects nationwide and put thousands of people out of work.

Facing a Sept. 30 deadline, officials are mindful of the deadlock that occurred this month over extension of funding for the Federal Aviation Administration. That cost an estimated $350 million in tax revenue and led to a partial agency shutdown that put 4,000 FAA employees and tens of thousands of construction workers out of work for two weeks.

Both the federal authority to collect the 18.4 cents a gallon in federal gas tax and authorization to spend the revenue on transit and highway projects are due to expire.

“When Congress comes back, they’re only going to have 11 days to take action,” said Susan Martinovich, president of the American Association of State Highway and Transportation Officials. “There is a crisis brewing.”

Until the FAA extension turned into a major test of wills between House Republicans and Senate Democrats, it was considered relatively routine for Congress to extend current funding while working on big spending packages.

The Senate balked when the House sent over an FAA extension with other provisions attached. The Senate finally buckled and approved the extension, raising the fear that House Republicans might repeat the move when that extension expires Sept. 16 and when the two surface transportation measures come due two weeks later.

The state administrators said that the Senate had committed to passing a six-month surface transportation extension but that House Transportation Committee Chairman John L. Mica (R-Fla.) had not responded to their inquiries.

Although the two houses are in final negotiations over a long-term FAA reauthorization, neither the House nor Senate has approved a long-term surface transportation bill. State officials consider long-term funding plans essential because they need to be confident that funds will be forthcoming when they launch highway and transit projects.

“We need to have a long-term reauthorization of the transit and highway programs, and they need to be funded at the same level, at least in the near future, at what they’re funded today, which is about $42 billion for highways and $11 billion for transit,” Martinovich said in Louisville on Tuesday after meeting with Southern state highway administrators.

Congressional efforts to pass a major surface transportation funding bill have been hamstrung because the primary source of federal transportation funding, the gas tax, has not kept pace with the nation’s needs.

The two houses have come up with strikingly different proposals, though neither has formally introduced a bill.

The House has talked of a six-year plan to provide about $35 billion a year, a sum that Mica says can be used to leverage double that amount through public-private partnerships. The Senate proposal would provide about $109 billion spread over two years.

If the cuts proposed by the House become law, 500,000 jobs would be lost, Martinovich said. “States may need to stop or decrease maintaining a third of their highways,” she said.

But with neither bill even in written form, the immediate prospect is for twin extensions — one allowing for collection of the gas tax and the other to permit spending — when the current authorizations expire next month.

“We’re facing a far more dire circumstance [than the FAA shutdown], where the entire federal aid program for highways and transit would shut down Oct. 1 unless Congress extends the revenue title,” said John Horsley, executive director of the association of state transportation officials.

Mike Hancock, Kentucky’s transportation secretary, said state officials are watching Congress “very, very carefully.”

“Do we have confidence that Congress will take care of everything they need to take care of in the 11 days? I look back a couple of weeks, and my confidence is shaken,” Hancock said. “It’s all in the hands of our members of Congress.”

If the authorizations are allowed to expire, state officials said, they would not be able to put projects out for bid and would have to begin shutting down projects underway. Since states spend money from their own coffers and then file for federal reimbursement, they would be out on a limb if they let work continue when federal funds were no longer guaranteed.