U.s. Must Boost Gas Tax, Transportation Expert Says

More Federal Money Needed For Aging Roads And Bridges

Without new revenue, Horsley said, Congress must transfer $5 billion to $7 billion to replenish the highway trust fund during the current fiscal year or watch as road projects grind to a halt. He said $8 billion to $10 billion would be needed for the fiscal year that begins in October.

Obama and others have called for passage of an 18-month stopgap funding measure, saying that Congress has its plate full with health care, energy and other issues.

Rep. Elijah E. Cummings, who also addressed the summit, said he and other House leaders disagree with Obama and want to pass a broader bill this year.

The Baltimore Democrat said the United States has put off investing in its infrastructure needs for too long, noting Monday's fatal crash on Washington's Metro subway system and the collapse of an interstate bridge in Minnesota in 2007.

But Cummings said that with unemployment hovering around 9 percent, it would be "difficult" to raise the gas tax.

"We're in a mess," he said.