NOTE TO READERS: Today I begin a six-month leave of absence to write a book. I'll miss Cityscape and MinnPost, and I'll miss you. See you in November! — Steve Berg

DULUTH — At a session with grad students and faculty here on Saturday, Rep. Jim Oberstar tried to sort out some of the confusion over how Americans will be asked to pay for the massive repairs and expansion needed in the nation's deteriorating transportation system. But in the end, he sowed some confusion of his own by reversing himself on a controversial plan to begin charging drivers by the mile.

A mileage-based tax will not be included in his writing of the new six-year transportation bill now before his House Transportation and Infrastructure Committee, Oberstar said. Instead, his committee will "promote mass transit and a wider range of choices than people now have" as a way to reduce petroleum demand and tailpipe emissions. Last year's high gas prices and this year's bad economy are already reducing the miles Americans are driving, he told an assembly at the University of Minnesota's Duluth campus.

Earlier last week, Oberstar was singing a different tune. Asked about funding options, he told the New York Times that he would consider both a temporary gas-tax increase and the development of a mileage charge. The committee has no choice but to seek the new mileage charge because a trend toward efficient cars and less driving has critically depleted federal gas tax revenues, he said.

"We will have multiple sources as we go into the authorization period. Vehicle-miles- traveled will be one," Oberstar said. He told the Times that a mileage tax would more accurately measure the effect a driver has on congestion as well as on the wear and tear of road and bridge surfaces.

Possibly a pilot project in the bill
So, why the change? No change really, said John Schadl, Oberstar's communications director. Yes, Oberstar is interested in exploring the feasibility of a mileage-based tax. Yes, there may be pilot projects included in the bill. But the technology isn't yet mature enough to put a mileage tax in place. So, no, it's unlikely that a mileage-based tax will be a part of the six-year bill.

"They need to look at the full scope of the bill before they look at how to fund it," Schadl said. The committee will consider a variety of funding sources when the time comes, he said.

Oberstar said on Saturday that he's planning a June rollout for the bill. Maybe by then the Obama administration will get its story straight. There has been more than a little confusion at the White House about how to pay for fixing and adding roads, bridges and transit systems.

As a candidate, President Obama promised an aggressive approach. Then, last month, a stern report from the National Transportation Infrastructure Financing Commission described the problem's scope. Governments at all levels are spending only a third of what's needed, the commission said after two years of study. Because the shortfall has reached a massive $200 billion a year, "our safety, economic competitiveness and quality of life are at risk," it said

Current federal gax tax won't do the job
The federal gas tax — 18.4 cents a gallon — simply isn't delivering enough revenue to do the job, the report continued. As a result, the blue-ribbon panel's key recommendation: move toward charging drivers for each mile driven, commonly called a VMT (vehicle miles traveled) tax. The tax would be calculated and enforced by a satellite-based monitoring system. Pilot programs are now underway in Oregon and several other states.

As the report surfaced, Obama's transportation secretary, Ray LaHood, signaled his agreement. "We should look at the vehicular miles program where people are actually clocked on the number of miles that they have traveled," he said.

But LaHood was immediately scolded by Obama's press secretary, Robert Gibbs. "I can weigh in on it and say that it is not and will not be the policy of the Obama administration." When a reporter protested that LaHood had said the VMT tax should be considered, Gibbs said sharply, "Well, call him back."

'Slapped down by know-nothings'
That's where Oberstar entered the debate by standing up for LaHood and the mileage tax idea. He told Congressional Quarterly that LaHood "had the temerity to think … and what did he get? Slapped down. He's a good man. A decent man. Don't let him get slapped down by know-nothings." Oberstar suggested that Gibbs say out of transportation policy. "I've got news for you," he said. "Transportation policy isn't going to be written in the press room of the White House."

That brings us to Saturday's session at the University of Minnesota's Duluth campus. As Oberstar finished his remarks, I asked him if he would, indeed, include a mileage tax in his new six-year bill, as he had apparently signaled with his defense of LaHood.

He said he would not. "No, not VMT," he said, launching into a discussion of promoting more options for travel and creating a level playing field for mass transit and auto projects, a fix often referred to as "modality neutrality."

I asked, then, how the Obama administration expects to pay for infrastructure fixes, considering the president's objection to both the new mileage tax idea and to raising the current gas tax. (LaHood had said earlier this month that he would not pursue a gas tax increase. "With the economy the way it is right now, trying to propose a 10-cent-a-gallon increase in the gasoline tax is not going to fly anywhere in America, including Washington, D.C.," he had said.)

Oberstar answered by retelling the anecdote about how Obama's press secretary should stay out of transportation policy and about how his committee will write the new provisions.

My view? Gax-tax increase is unavoidable
So where does that leave us? My own view is that a federal gas tax increase is unavoidable, and that all kinds of pricing experiments, including mileage and weight-based taxes ought to be tried. We cannot fix our decrepit roadways or expand non-auto transportation options, and we cannot honestly confront climate change or reduce our dependence on foreign petroleum unless Americans are charged a fairer and truer price for driving.

I'm not saying there aren't huge benefits to the car. I love to drive. I love my car and the freedom it provides. But the costs of driving far exceed the $1.80 per gallon we're now paying at the pump. Some suggest that the hydrogen car is just around the corner and will solve everything. But hydrogen fuel cell and fusion technologies are perpetually 20 years down the road. Besides, even if we suddenly had clean-burning cars, the problems of congestion and wear and tear on roadways and bridges would not go away.

Two Washington Post editorials and an adjoining discussion tell more about the mileage tax option. And a National Journal blog offers some expert opinions.