Sen. Mary Margaret Haugen, D-Camano Island and chairwoman of the Transportation Committee, predicted tonight that a bill to fund a proposed $1.9 billion, deep-bored Seattle tunnel will pass the Senate.

"There's a lot of support," she said, after a hearing, where members raised few objections.

The tunnel is the biggest piece of a Highway 99 rebuild that costs $3.1 billion, including a new elevated segment and interchange in Sodo.

The only discouraging words came from Sen. Derek Kilmer, D-Gig Harbor, who wondered if state taxpayers would be on the hook if cost overruns occur. (Yes, they would.) Sen. Chris Marr, D-Spokane, held out hope that if the tunnel is under budget, the leftover money would go to other projects.

Tolls on the tunnel should be able to cover any overruns, Haugen said.

Senate Bill 5678, co-sponsored by Sen. Ed Murray, D-Seattle, would have the state dig the tunnel, and spend $2.4 billion in gas taxes and federal grants previously earmarked for Highway 99. And it would require tolls to fund $400 million or more. The Port of Seattle has already pledged $300 million, making the numbers add up to $3.1 billion.

Seattle will consider additional city taxes for parks, utility relocation, streetcars, a waterfront seawall replacement, and road improvements.

King County has asked the state to allow a countywide car-tab tax to fund Metro transit buses, but Haugen opposes that. Ron Posthuma, assistant transportation director for King County, said he's in talks with Gov. Chris Gregoire to come up with another bus funding plan the state can accept.