As the Senate Environment and Public Works Committee advances a highway bill ( S 2322 ), Thomas R. Carper, D-Del., is playing the role of both an authorizer and a Finance Committee member looking for ways to pay for it.

Carper, one of the bill’s writers as chairman of the Transportation and Infrastructure Subcommittee, said he has taken it on himself to explore options on revenue ideas in talks with Finance members.

He said his goal is “to develop a Senate consensus on funding [and] hopefully a congressional consensus on funding” to cover Highway Trust Fund road and transit programs for six years.

Carper says rather than any single, large revenue plan, he “ could see almost a tapestry of different funding mechanisms” to cover the bill’s cost and give states the certainty of a long-term authorization.

He says he plugs his own proposal in those talks — to phase in small increases of 3 and 4 cents a year in federal per-gallon gas taxes over four years and then index that fee for inflation. The increase would come in such small doses that people would not really notice at the pump, Carper said, but would be enough to restore the purchasing power of the gas tax to when Congress last raised it in 1993.

That idea is not expected to gain much support on Capitol Hill, and it is not backed by the White House. Carper says, though, it will take all sorts of ideas to pay for U.S. infrastructure.

The bill that was headed to a Thursday morning markup, for instance, includes a section for the Transportation Department and states to research and test financing alternatives. Carper said that would let the states test ideas that might suit some of them but not others.

But that’s after the legislation is done, and the ideas that percolate from the research would only spread later.

For now, Carper said, there’s the near-term need to bolster the trust fund by late summer, when its highway account is projected to run low, plus the long-term need to keep paying for programs.

“There is immediate need, there is more of a mid-term need, and there is more of long-term need,” for revenue, he said. “Which would suggest that there’s not just one ‘silver bullet’ to meeting our financing needs over the next six years, but maybe a number of silver BBs.”

But Carper also said some of his discussions with other senators have turned up a basic problem: “It’s interesting that a couple of people said, ‘Gosh, we’ve got to keep spending money on these transportation projects across the country — but we’re not willing to pay for it.’ “