Transportation officials also point out that TIFIA doesn't provide grants but loans, which of course have to be repaid. That requires a dedicated revenue stream, such as tolls, fares or local taxes, which knocks most projects out of the running.

But for major bridges, highways and transit lines with the means to pay back loans, TIFIA offers low interest rates, a five-year grace period and a 35-year term. James Bass, Texas DOT chief financial officer, said in e-mailed comments, "The flexible payment terms and low interest rates make TIFIA a great solution for a number of projects." TxDOT had a project selected in the 2012 round and has used TIFIA aid on four earlier projects.

D.J. Gribbin, a Macquarie Capital managing director and its head of government advisory affairs, says of TIFIA, "It is best used to attract private equity to a project. … It shores up the financing for a project in such a way that the private sector becomes much more interested."