IN A better Washington, a bipartisan proposal from Sens. Bob Corker (R-Tenn.) and Chris Murphy (D-Conn.) wouldn’t elicit any special praise. In the Washington we have, their transportation plan, which would raise the gasoline tax modestly to pay for the nation’s roads and rails, is a portrait of political courage. By daring to cross the aisle and propose what many know — but won’t admit — to be good policy, Mr. Corker said he wants “to break the ice” freezing lawmakers from doing the right thing. It’s time for his colleagues to listen to reason.

Past time, really. The federal government’s Highway Trust Fund has traditionally relied on the gas tax to finance the building and maintenance of the country’s transportation infrastructure, but lawmakers haven’t raised the tax since 1993. The result has been regular funding crises as the trust fund runs low, state officials fret that they will have to postpone or cancel projects, contractors become wary of doing business with the government and Congress scrambles to scrape up funding. Round after round of gimmickry has shored up the transportation budget with general funds. Instead, those who use the infrastructure should be on the hook. The gas tax remains a relatively good way of accomplishing that.

The trust fund is once again in dire straits, due to run out sometime in the summer. The Congressional Budget Office figures that, at current gas tax levels, it will fall $13 billion short of its obligations next year and $160 billion short over the next 10 years. Mr. Corker and Mr. Murphy’s solution is to raise the gas tax by 12 cents a gallon over two years, then index the tax level to inflation. That would redress the erosion in the value of gas tax revenue over the past two decades and prevent inflation from eating into gas tax receipts in the future.

Because that would open lawmakers to criticism that they raised taxes, Mr. Corker and Mr. Murphy have proposed linking the new revenue to permanent extensions of a variety of popular tax breaks, such as one for corporate research and development. But the two things shouldn’t be linked. The linkage that matters is this one: Truck and automobile drivers use roads. Road construction and maintenance costs money. A gasoline tax that keeps pace with inflation ensures that drivers help pay for that cost.

With the increasing (and welcome) fuel efficiency of automobiles, the gasoline tax can’t be a complete answer to the nation’s infrastructure needs. But it is a big part of the answer, and Congress should follow the common-sense leadership of Mr. Murphy and Mr. Corker.

This May 28, 2010 file photo shows traffic jammed in both directions on Interstate 405 on the Westside of Los Angeles. (Reed Saxon/AP)