One of many items expected to be considered by the state Legislature this session is a resolution recommending three potential plans for the west side interchange, part of the State Route 520 bridge replacement project.

After 16 months, mediation participants ­— including commercial entities in the Seattle area — finalized the Westside Project Impact Plan, a report detailing the varying factors of the three interchange options, known as options A, K and L.

A final decision will not be made as to which option will be implemented until after an Envrionmental Impact Statement can be completed, which could take up to two more years.

The project, initially given a $3.9 billion budget, would replace the aging bridge structures with safer, more reliable ones and would expand the four-lane corridor to six, according to the Washington State Department of Transportation (WSDOT).

A four-lane bridge would be expected to open to the public by 2014 with the additional two lanes opening by 2016.

Among other things, all three options would add lanes above or below the Montlake Cut to alleviate traffic, eliminate the Montlake Flyer Stop, relocate the Museum of History and Industry and add pedestrian and bicycle facilities along the corridor.

In addition to other common factors, each option goes over budget by a minimum of nearly $1 billion.

To help pay for the project, tolls will be collected electronically on the SR 520 corridor.

“We evaluated 10 different scenarios, including tolling 520 alone and tolling both 520 and I-90 bridges,” said David Hopkins, lead staff member of the tolling implementation committee for the project.

Of the 10 scenarios, only one option, which tolls SR 520 alone, met the $1.5-$2 billion revenue target set by the state Legislature.

Under this scenario, tolls would start in 2010 and would range from $1.80-$3.50, with an average cost of $2.36 expected.

The tolls would be primarily collected through transponders that would be placed in cars’ windshields and scanned whenever a driver crossed a toll area.

The transponders cost approximately $12, Hopkins said.

The three options

At an estimated cost of up to $4.8 billion, option A represents the cheapest of the three options and would add a second drawbridge with pedestrian facilities that would run parallel to the existing Montlake Bridge. An auxiliary lane would be added across Portage Bay.

Option K includes more comprehensive plans than option A and could cost as much as $6.7 billion.

“Option K is the most expensive, yet most ambitious option,” said Jonathan Dubman, Montlake Community Council’s representative.

Option K would relocate the Montlake interchange entirely, moving it east to McCurdy Park. From there, a four-lane tunnel would stretch under the Montlake Cut beneath the water and emerge at Montlake and Pacific.”

This would separate freeway and local traffic, allowing Montlake Boulevard to become a local traffic roadway.

Option L, estimated to cost up to $5.2 billion, would also relocate the interchange to the east. But rather than an underground tunnel, a drawbridge would span from McCurdy Park to Montlake Boulevard NE and NE Pacific Street.

At a public hearing at Seattle City Hall Tuesday, speakers were divided between options A and K. None spoke on behalf of option L, Seattle City Councilmember Jean Godden said.

According to Dubman, option K is the one plan that provides a reliable way for buses to get from the Eastside to the UW and its light rail station without drawbridge openings.

“It is very important that additional transit hours and service hours be funded as part of the High Capacity Transit Program,” Doherty said. “More important would be the Sound Transit station, operational 2016, outside Husky Stadium.”

While the light rail will run through the UW regardless of which SR 520 option is chosen, the two projects affect each other and could pose challenges to the other’s progress as they begin.

Options K and L would also pose an inconvenience to the UW by requiring Husky Stadium’s southern parking lot to be torn up and relocated.

“While (option) A obviously has the least impact on the University … we do not have a preference to the three options,” said Theresa Doherty, assistant vice president for regional affairs at the UW.

Doherty said the UW would accept any of the three options, as long as it meets a list of requirements: allows the UW to grow in the future by retaining the building capacity of property south of Husky Stadium, funds the necessary transit service and facility improvements resulting from the Montlake Flyer Stop’s removal, replaces any lost parking, does not impair traffic on Montlake Boulevard and protects the UW’s assets.

The majority of discussion in the legislature is expected to center around tolling possibilities and funding for the rest of the project, Hopkins said.

Reach reporter Joy Yagi at news@dailyuw.com.