“It brought a smile to my face,” he says in reference to McCurdy’s lobbying push. “Because for years the industry has said they support a gas tax, but they’ve never actually lifted a finger to make it happen.”

Of course, activists such as Becker note ruefully that this lobbying effort would have meant a lot more when automakers had far more clout than they do today. “They clearly have a lot less influence than they used to,” Becker says. “But it would be welcome to have them try to use it for something other than shaking the tin cup for their own benefit.”

McCurdy appears to be walking the same walk on the gas tax as most environmentalists: touting its environmental benefits as well as its importance to national security, as a means of reducing the flow of revenue to oil-rich regimes. In the bigger picture, though, self-interest remains clearly in play. Only a few car models meet the fuel economy standards the automakers accepted in May, which will rise up to 39 miles to the gallon for the average vehicle sold in 2016.

The industry’s success will depend not so much on what comes off assembly lines, but what drives off dealer lots. For new fuel efficiency rules to prove themselves economically, they have to be reflected in overall sales, not just in new production standards.

If Congress doesn’t act to raise gas prices, McCurdy argues, his members will have trouble making the math work in favor of more fuel-efficient product lines. “If the policy is to keep energy prices artificially low, then I think it hurts the industry,” McCurdy says.

It could well be, in other words, that as with other climate change and environmental initiatives, industry interests are starting to align with the green-advocacy push for a higher gas tax. Becker, for one, says “a well-structured gas tax” — one that is phased in and includes credits for the poor — “is something that many environmentalists support.”

Even conservatives, such as GOP Sen. George V. Voinovich of Ohio and columnist Charles Krauthammer, have endorsed the idea of a steeper gas tax as a means of paying for infrastructure improvements, meeting environmental goals and keeping money out of the hands of foreign oil-producing countries.

Economists say the idea makes sense, too. Robert N. Stavins, director of the Harvard Environmental Economics Program, argued in a recent opinion article that “gasoline prices are a much more effective — and more cost-effective — means of cutting gasoline demand” than tough fuel economy rules.

Taxing Dilemmas

There’s another curious feature of the emerging gas tax debate: The Obama administration and many Democrats on Capitol Hill are standing in the way.

In March, Transportation Secretary Ray LaHood told Voinovich that the idea was “off the table for now,” explaining that the Obama administration could “ill afford to tell people we’re going to raise the gasoline tax” in “these hard economic times” and “with so many people out of work.”

At the same hearing of the Environment and Public Works Committee, Chairwoman Barbara Boxer , a California Democrat, said she was also “averse” to a gas tax increase.

But gas tax collections have fallen recently in response to higher gas prices and a rare drop in driving. That development, combined with the widely held view that America’s transportation infrastructure needs to be comprehensively overhauled — the kind of outlay that traditionally gets funded through gas taxes — will likely force congressional Democrats to give the issue a second look this session.

If nothing else, proposed gas tax hikes will figure prominently in the reauthorization of a big highway funding bill that is scheduled to move this year. Self-interest will also be a central factor in that debate, since lawmakers typically load the legislation with local infrastructure improvements that make for popular support in re-election bids.

Oil companies also maintain that they’re prepared for a tax hike. John Felmy, chief economist at the American Petroleum Institute, the industry’s Washington trade group, says that a tax increase clearly earmarked for infrastructure would benefit his members, though he adds they would oppose any hike that would be regressive and burdensome to average Americans.

House Transportation and Infrastructure Chairman James L. Oberstar , a Minnesota Democrat, has said he would consider an increase in the tax as a means of funding the infrastructure improvements he wants in this year’s bill.

But Oberstar says he’s also considering a vehicle mileage tax, which would require drivers to pay a fee based not on how much gas they use but how far they drive. That wouldn’t provide an incentive to favor one type of vehicle over another, and therefore wouldn’t help automakers as much as a gas tax increase.

All in all, the gas tax hike will likely prove a tough sell in a recession-minded Congress. But McCurdy says he’ll keep pressing, and with the new fuel economy rules not slated to take full effect for seven more years, he should have ample time to make his case.

But already, he says, with gas prices down 40 percent from their peaks of last summer, buyers are trending back toward bigger cars. And while committed environmentalists may buy a hybrid out of a sense of social conscience, average Americans can’t justify it. “It costs $5,000 more for the hybrid,” McCurdy says, and “the math does not add up” for most consumers. “There are people making that calculation every day at $2 gas.”

What might prompt policy makers to change their tune? McCurdy says he hopes it’s good sense. “I hope it’s not another oil crash. I hope it’s not another war. I hope it’s not another catastrophe or attack.”