New funding strategy for 520 bridge

Local elected officials, in hopes of creating buzz for this fall's "Roads & Transit" ballot measure, say they've figured out how to pay for a new Highway 520 floating bridge.

Still, the project is a long way from being ready to go.

The latest strategy, released today, improves on earlier versions by slashing a potential $340 million in construction taxes and financing costs for a possible $4.4 billion, six-lane span across Lake Washington.

Future tolls might be up to $6 per round trip after the bridge opens in about a decade, the same toll the Tacoma Narrows Bridge will charge by then.

In the latest version, the Regional Transportation Investment District would fund its highway projects using high-rated, low-interest state bonds, or financial backing from the state, for a potential savings of $200 million. The regional group also proposes that $140 million in expected sales tax revenue from the Interstate 405 and Alaskan Way Viaduct projects be funneled into Highway 520, instead of the state's general fund.

And the ballot measure itself includes $1.1 billion for the bridge.

Even after those steps, the funding plan won't be totally solid. No real plan exists for the tolling. Previous studies showed that an average $3.07 round-trip toll (peaking at $4.60 during rush hour) would pay off $700 million in construction debts. But at an average of $6, the toll would cover $1.2 billion.

Second, the cost estimates are subject to change.

A design has not been picked yet for the bridge. Its layout through Seattle wetlands is so controversial that a mediator will work with neighbors and interest groups. In all, the officials announced they can raise $3.3 billion to $4.4 billion for the new bridge. (The $4.4 billion estimate is a midrange figure for the "Pacific Interchange," a relatively elaborate version that includes an exit bridge over Union Bay, to Husky Stadium.)

"I think it's important for people to see that it's doable," said state Rep. Judy Clibborn, D-Mercer Island and chair of the House Transportation Committee, who helped devise the new funding strategy.

The existing four-lane span, completed in 1963, could fail in the event of a severe windstorm or earthquake.

On Thursday, the RTID's planning board, which is a delegation of county council members, will issue its list of road projects for the November ballot in Snohomish, King and Pierce counties. Those will be combined with Sound Transit rail extensions in a joint ballot measure.

Together, construction costs for the road and transit projects are estimated at $17.7 billion in 2006 dollars. Total spending would be about $37 billion through their completion in 2027, if inflation, finance costs, operations, overhead and cash reserves are included.

Mike Lindblom: 206-515-5631 or mlindblom@seattletimes.com