IN SOUND TRANSIT'S most recent lifesaving deal, the agency made the wild assurance to the University of Washington that it would solve any traffic problems resulting from the 45th Street light rail station. Given that the line is scheduled to end on 45th Street -- drawing cars from far and wide, picking up and dropping off passengers -- Sound Transit's promise seems about as reliable as the assurances WTO protesters gave former Seattle police chief Norm Stamper that they would play nice last November.

While the Sound Transit/UW agreement is obviously far from perfect, it is the perfect metaphor for the mirage known as light rail. After all, the deal -- hammered out in the 12th-floor offices of light rail diehard Mayor Paul Schell around 7:00 p.m. on April 5 -- plainly represents just how mysterious the $2 billion project has become. Case in point: No one knows how the hell Sound Transit is going to deliver on its promises to the UW or how much those promises are going to cost. Yet the project barrels forward.

The heart of the conflict between the university and Sound Transit involved the UW's desire to have the line run all the way to Northgate -- an estimated $415 million add-on to the $1.92 billion, SeaTac-to-45th Street route. The UW feared that without extending the line to Northgate, the roads around their 45th Street campus would be overrun with traffic.

The UW agreement -- a hoop Sound Transit had to jump through in order to submit a funding request to the Feds -- didn't assuage the UW's concerns. "We were asking for assurances they just couldn't give," says UW's Assistant Vice President of Regional Affairs, Bridgett Chandler, who participated in the last-minute meeting. All the same, UW signed off on the deal. Why? "It was legally binding," Chandler says. In short, Sound Transit is now obligated to deliver something it can't.

So, what exactly did Sound Transit promise to do? The beleaguered agency said it would "fund a before-and-after study to determine impacts, and to mitigate those impacts." Chandler acknowledges that the only way to truly mitigate the impacts (read: traffic) is by building a Northgate station. "That or a magical anti-traffic wand," she says.

Chandler has every reason to be cynical. Sound Transit's plan to reach Northgate boils down to this: Beg for more federal money. However, given that Sound Transit filed a request to the Federal Transit Authority (FTA) on April 14 for $900 million (just to meet the original goal of getting to 45th Street!), an additional half-billion in federal dollars doesn't seem likely.

"We're extremely skeptical that there will be funding for Northgate," says straight-shooter Kate Joncas, executive director of the Downtown Seattle Association. The DSA is the powerful Seattle business lobby that is challenging Mayor Schell on the light rail issue, urging its 400 members -- including Nordstrom, the Bon Marché, and the Seattle Symphony -- to oppose the plan unless Sound Transit lines up additional funding.

In addition to the illusory Northgate pledge made to the UW, the agreement is symbolic of the precarious light rail project for another reason. In the agreement, Sound Transit promised to pay for added building costs to the new UW law school, protect campus lab research from vibrations, and pay to offset the general impacts of construction. Here's the problem: No one agrees on what the total bill for these mitigation costs will be. (The same financial unknowns haunt Sound Transit's budget in Rainier Valley, the downtown tunnel, and Tukwila.) "There aren't any hard and fast numbers because Sound Transit doesn't have any hard and fast answers," says Chandler.

Deputy Light Rail Director Mary Jo Porter says mitigation costs in areas like Rainier Valley are covered. She did acknow-ledge, however, that there are mystery costs associated with the UW. "In the U-District I cannot say 100 percent that the costs are [within] budget." She's quick to point out, though, that the possible budget overruns aren't the result of any new mitigation costs associated with the recent deal. Any additional costs, she says, would come from increasing real estate values.(However, The Stranger compared Sound Transit's original UW budget with the post-agreement budget and found $4.6 million in extra mitigation costs.)

Sound Transit's final plan is due in the FTA's offices on June 1. If (and that's a big if) the FTA is satisfied, it will forward the funding request to Congress on August 1. Congress will make its funding decisions on October 1. While Mayor Schell may have the clout to strong-arm the UW's Board of Regents, Mr. WTO certainly doesn't have much sway in D.C. The bottom line? Lack of community support and the department's budget-fudging could jeopardize federal funding, and in turn, the whole project. The mayor and Sound Transit should keep that in mind when they're making tenuous promises like the most recent one to the UW.