Seattle political leaders remain strongly opposed to building a new Alaskan Way Viaduct, despite a new poll showing voters prefer a new viaduct to a more expensive tunnel by a 2-1 ratio.

Mayor Greg Nickels restated his support for a tunnel this weekend even though a poll commissioned by The Seattle Times found support for a new viaduct. City Council President Nick Licata predicted the poll wouldn't sway most on the council from arguing against a viaduct.

The city's objection to a new viaduct could prompt a battle with state leaders should they choose that option to replace the earthquake-damaged section of Highway 99. Gov. Christine Gregoire has said she'll decide next month between a new viaduct and a tunnel.

Nickels vowed to keep fighting for a tunnel, calling a new viaduct "unacceptable." He said he would seek help in trying to persuade Gregoire from a coalition of environmental, business, and civic groups that have opposed a new viaduct.

The mayor also expects help from the council, which voted 7-1 to replace the 53-year-old Alaskan Way Viaduct with a tunnel.

"I don't think the [poll] numbers are going to persuade the council to change," said Licata, a tunnel opponent. "A majority of the council has a vision for the city" with a more open waterfront.

Councilman Peter Steinbrueck agreed. "I see a huge battle over this coming," he said.

Council members have said a new viaduct would violate city height limits on waterfront structures and shoreline-protection rules.

Licata called those warnings a "political maneuver" that wouldn't hold up in court. The state may prevail in a legal battle, Steinbrueck said, but a new viaduct would be contrary to city laws.

Gregoire said that if she decides on a new viaduct, she doesn't want city officials to fight her decision. "I hope we never ever get to that," she said, because it would mean "delays, running up the cost, and putting people's lives at risk."

The poll of 400 registered Seattle voters was conducted Thursday and Friday by Elway Research. It found that 25 percent of voters favored a tunnel, while 51 percent wanted a new viaduct. About one-quarter of those polled were either undecided or wanted to tear down the viaduct and route traffic onto surface streets.

Those who wanted a new viaduct or the surface-street option cited cost as the main reason. The latest state estimates put the likely cost of a tunnel at $4.6 billion and a new viaduct at $2.8 billion. The state has not studied the surface-street option, saying it's not viable because surface streets couldn't handle the 106,000 vehicles that now travel the viaduct each weekday.

But Steinbrueck and state Rep. Ed Murray, D-Seattle, said it may be time to reconsider the surface-street option. The poll showed that roughly half of Seattle voters do not want a new viaduct, said Murray, a tunnel supporter. "In my mind, we're not done with the discussion," he added.

Nickels said Saturday that the surface option is his preferred fallback plan.

Both the viaduct and tunnel are too expensive, Steinbrueck said. "I think we should look for a more cost-effective solution that is neither an aerial highway or tunnel," he said. A lukewarm supporter of a tunnel, Steinbrueck has urged tearing down the viaduct and routing traffic onto surface streets, with beefed-up bus service. He wants the city, county and state to study that option. He believes it could save money that could be used for projects such as a new Highway 520 bridge across Lake Washington.

It could be a tough sell, though.

Gregoire said she thinks the choice is between a tunnel or new viaduct. "I don't, candidly, see the surface option as viable," she said.

Sen. Mary Margaret Haugen, D-Camano Island, chairwoman of the Senate Transportation Committee, agreed. "I don't want to start studying anything more. It's time to put money into building something," Haugen said.

House Speaker Frank Chopp, D-Seattle, said the poll showed only 15 percent of voters supporting a surface-street option, and he urged city officials to reconsider a new viaduct. "The first thing we should do is take the tunnel off the table because it's simply not affordable. Then we should work together to see what kind of elevated highway could be done that is affordable and decent in terms of design," Chopp said.

Nickels said he was comfortable going against voter sentiment expressed in the Times' poll. He pointed to similar popularity problems that hounded Sound Transit's downtown-to-the-airport light-rail project.

"I've gone through the peaks and valleys of building a light-rail system in this city, and there were times in 2000 and 2001 where it was about as popular as Prohibition," said Nickels, a Sound Transit board member. "We stuck it out and in 2009 we're going to open light rail to the airport, and today if you took a poll there would be consensus that it was the right thing to do."

Staff reporter Ralph Thomas contributed to this report. Bob Young: 206-464-2174 or byoung@seattletimes.com.