WASHINGTON (Reuters) - U.S. lawmakers on Wednesday said Congress must find a way to pay for a massive looming shortfall in funding to pay for crumbling highways, bridges and other infrastructure.

The U.S. Capitol Building is lit at sunset in Washington, U.S., December 20, 2016. REUTERS/Joshua Roberts - RC160F87DBA0

Representative Bill Shuster, who chairs the House Transportation and Infrastructure Committee, said at a hearing he is working to find a “big broad bipartisan infrastructure bill” but acknowledged new revenue must be found.

Congress has transferred nearly $140 billion to the Highway Trust Fund since 2008. In order to maintain current spending levels, lawmakers would need to approve an additional $107 billion from 2021 through 2026.

Some lawmakers suggested hiking the federal gasoline tax, which at 18.4-cent-a-gallon has not been raised since 1993 and rising U.S. vehicle fuel efficiency is reducing revenue to pay for road repairs.

While some 31 states have hiked gasoline taxes since 2012, many key Republicans in Congress strongly oppose a federal gasoline tax hike.

“There’s been no political price to pay,” Shuster said, for state politicians hiking gasoline taxes. He said Congress will pay a “price” if they do not have a funding fix. “We are already paying it in congestion, bad roads and failing bridges.”

President Donald Trump last month endorsed hiking the federal gasoline tax by 25 cents a gallon in a meeting with lawmakers about funding his infrastructure spending proposal, a Democratic lawmaker said. He has not endorsed it publicly and the White House would not confirm or deny the report.

“If you don’t increase taxes we’re not having an infrastructure bill and we’re doing nothing,” Representative Peter DeFazio, the top Democrat on the panel, said at the hearing. “We have to have real money.”

The American Trucking Associations and U.S. Chamber of Commerce both testified in favor of boosting gasoline taxes on Wednesday.

But Representative Sam Graves, a Missouri Republican, said there is little chance of winning support in the House to hike gasoline taxes, but said a solution must be found. “There simply isn’t any money left under the couch cushions,” he said.

Trump wants to use $200 billion in federal funds to try to stimulate $1.5 trillion in infrastructure improvements over 10 years but would cut an equivalent amount in projected infrastructure spending from the federal budget as it shifted more costs to states and cities.

Senate Democrats Wednesday proposed $1 trillion in new federal spending paid for by repealing some tax cuts approved in December.

Trump would make it easier for states to impose new tolls. Last month, the White House praised an experimental program in Oregon that charges a mileage tax to volunteer drivers. But ramping that up nationally could take a decade, experts testified Wednesday.

Congressional aides say it is looks increasingly unlikely that a major infrastructure package will be approved this year, citing the pending November elections and a glut of issues on the calendar.