WASHINGTON — Congress yesterday sent President Bush an $8 billion rescue package for the federal highway trust fund. The infusion comes as the trust fund, which relies on declining revenues from the federal gas tax, verges on going broke, threatening road and bridge projects in every state.

The House passed the measure on a 376-29 vote yesterday, a day after the Senate overcame objections from conservative senators and passed it on a voice vote. The legislation transfers $8 billion from the Treasury’s general fund to the highway fund, ensuring that ongoing construction projects won’t be interrupted.

That includes $98 million for Montana roads, Senator Baucus, the Montana Democrat who is chairman of the Finance Committee, said. Mr. Baucus also said the move will help protect 3,500 jobs in Montana.

The White House had previously threatened to veto the measure, calling it “both a gimmick and a dangerous precedent that shifts costs form users to taxpayers at large.”

But the administration shifted positions after Transportation Secretary Mary Peters last week disclosed that the trust fund would run out of money this month, which would delay payments to states for infrastructure projects and threaten the jobs of hundreds of thousands of construction workers.

“We must act,” Rep. John Lewis, a Democrat of Georgia, said. “The trust fund is broke, out of money. Our state and local governments, drivers, construction workers and many others suffer when highway projects are delayed.” He and others pointed out that in 1998 the government moved $8 billion from the trust fund, then enjoying a large surplus, to the general fund for deficit reduction, and that this measure returned borrowed money.

It has long been anticipated that the 52-year-old trust fund would move into the red next year, a result of the reluctance of Congress to raise the gas tax, unchanged since 1993 despite inflation and soaring construction costs. The federal fuel tax is 18.4 cents a gallon, or 24.3 cents for diesel.

But the fund, which had a $10 billion surplus just three years ago, has had a rapid change in fiscal fortune as drivers, responding to higher gas prices, have curtailed their driving and switched to more fuel-efficient vehicles.

Ms. Peters on Wednesday commended the Senate for its swift action to address the immediate crisis but added in a statement that “Congress must eliminate the billions in wasted spending, thousands of unneeded earmarks and hundreds of conflicting and contradictory special interest programs in order to make sure states don’t face this situation again.”