Seattle's Convention Center is taking a close look at expanding, perhaps at a different location. It might complicate the coming legislative session if it puts its hand in the state trough of money for tourism-related taxes. Also crowding around the trough are the Huskies, King County arts, Seattle Center, KeyArena, low-income housing, Puget Sound cleanup, and more. And the Convention Center might topple some other interesting transportation dominoes.

The Convention Center, properly known as the Washington State Trade & Convention Center, doubled in size in 2001 to its present 205,000 square feet. Center President John Christison says that he thinks it could add another 200,000 to 300,000 square feet to meet demand. He notes that Portland's facility has 350,000 square feet, and Vancouver will open a new facility in conjunction with the 2010 Olympics, also at 350,000 square feet. Denver, San Francisco, and San Diego have much larger meeting facilities.

Christison says a firm is currently doing an economic feasibility analysis, and if that looks good, the Center's architectural firm, LMN, will look at configurations and design. The goal is to have a proposal ready for the 2009 session of the Legislature, when other interests are jockeying for the hotel-motel taxes that primarily fund the Center and other stadium-related taxes as they expire and become available for other supplicants. The issue of these taxes grew heated in the controversy over saving the Sonics at KeyArena, after which Speaker Frank Chopp appointed a committee to weigh the many requests. These taxes are among the few that are available in the coming session, when hard times will argue against any tax increases.

"Business is good," reports Christison of the Center. It has some real advantages. The hotels are right close by, and it's located in the retail core of the city, while other facilities such as Portland's are off center and remote from the big hotels. Apparently rising airfares haven't hurt the business yet, and the Center has been able to fill in some slow months with local business. But it's an awkward facility, perched six to seven stories above the street so it can span the I-5 freeway uphill. One goal of the expansion is to have enough room so that conventions can run concurrently; now there are several days lost while one closes down and another moves in.

But where to expand? The present site is hemmed in by the freeway and other tall buildings that have grown up around it. Christison says there are three possible sites, each a stand-alone site several blocks away. One would be on the central waterfront, a spectacular site but one probably tied up for more years of uncertainty over the Viaduct. Another is Seattle Center, presumably replacing Memorial Stadium on the east edge, but this site lacks hotel and restaurant infrastructure. The third site, "which has the most allure," is the Convention Place Metro Transit bus station alongside the freeway and only a block north of the Convention Center. This site is owned by King County, which might lease the air rights for an expanded Center. People have tried for years to figure what to do with this site, where buses entire the Downtown Transit Tunnel.

One possibility definitely off the table is to build over the freeway, partly for reasons of expense, but mostly because the Center has become a bottleneck for I-5. If anything, there might be pressure to carve out more lanes under the Center, easing the narrowing. Other options are to convert some off ramps to through lanes, or to tunnel under I-5, adding lanes. All this, in turn, is related to the puzzle of the Alaskan Way Viaduct. If the "surface solution" prevails, dumping some of the Viaduct traffic onto I-5 and downtown streets, that could increase the demand for more lanes under the Center.

Might that even call for scrapping the existing Center and building a new one on another site? One King County source says he's heard just such a proposal, but Christison scoffs at the suggestion. Cary Moon, founder of the People's Waterfront Coalition, a chief advocate for the surface solution for the Viaduct, says she has not heard anyone advocate a removal of the Center, adding that all the current plans for I-5 simply reconfigure some off ramps and restripe other lanes to get more capacity.

And speaking of bottlenecks, what about Freeway Park, which spans the freeway just south of the Convention Center? One indication of the way the state Department of Transportation is keeping its options open in that area is its adamant resistance to an attempt to turn Freeway Park into a city landmark, filed two years ago and stymied by the state's resistance to locking up state property. Seattle is negotiating lots of issues with WSDOT, including the Highway 520 bridge and the Viaduct, so Freeway Park may turn out to be a bargaining chip in any future settlement.