FILE - An automobile drives over a pothole in Bloomfield Township, Michigan.
FILE - An automobile drives over a pothole in Bloomfield Township, Michigan.
WASHINGTON - Two U.S. senators on Wednesday proposed raising federal gasoline and diesel fuel taxes by 12 cents a gallon [3.2 cents a liter] over the next two years to keep a road and bridge fund from going broke.

The gasoline tax now stands at 18.4 cents a gallon, and the diesel tax at 24.4 cents a gallon. The politically sensitive levies have not been increased since 1993.

The senators' plan faces an uphill fight this year, with congressional elections coming in November.

Senators Bob Corker, a Republican, and Chris Murphy, a Democrat, called for the tax increase, with the new revenue going to replenishing the federal Highway Trust Fund.

The fund pays for about half the country's spending on transportation projects and is projected to run out of money by the end of August.

“If Americans feel that having modern roads and bridges is important then Congress should have the courage to pay for it,” said Tennessee's Corker, in a joint statement.

Murphy, of Connecticut, said, “I know raising the gas tax isn't an easy choice, but we're not elected to make easy decisions -- we're elected to make the hard ones.”

Groups ranging from the AFL-CIO labor federation and the U.S. Chamber of Commerce have lobbied Congress to boost fuel taxes. But there has been little appetite among lawmakers to raise the taxes in an election year.

Murphy and Corker called for raising the taxes by 6 cents a year over the next two years, while offsetting the increased federal revenue with other tax cuts. They also proposed indexing the fuel taxes to keep pace with inflation.