State considering three designs for west side of 520 bridge

State considering three designs for west side of 520 bridge

By Joshua Adam Hicks • January 25, 2010 9:50 pm
This rendering shows the proposed 520 bridge replacement with six lanes and a bicycle/pedestrian path.
This rendering shows the proposed 520 bridge replacement with six lanes and a bicycle/pedestrian path.

The state Department of Transportation on Friday released its supplemental draft environmental-impact statement for the western segment of State Route 520.

The report includes three design options for a new Montlake interchange, and WSDOT is looking for public input as it moves closer to selecting a preferred alternative this spring.

Plans are in the works to renovate the entire 520 corridor at an estimated cost between $4.5 billion and $6.7 billion, although the legislature has set a limit of $4.65 billion for the project.

Separate phases will take place along the eastern and western segments of the highway.

The Eastside segment will get continuous interior HOV lanes from Medina to SR-202 and a direct-access interchange for transit and HOV at 108th Ave. NE. Work on that portion could begin this year if funding becomes available.

Plans for the west side includes a bridge replacement and a new Montlake interchange.

State legislators have endorsed a six-lane replacement for the bridge with one new HOV lane in each direction.

Among the three Montlake-interchange alternatives, Option A would maintain the existing location of the interchange while adding a new draw bridge parallel to the existing Montlake Bridge.

Option K includes a new interchange roughly half a mile east of the existing one. The ramps would pass below the SR 520 roadway, with the northern leg of the interchange crossing beneath the Montlake Cut in a tunnel.

Option L would place the interchange in a similar spot, with ramps above the 520 mainline. The northern leg of the interchange would cross the Montlake Cut on a new draw bridge.

A panel of state lawmakers earlier this month recommended a variation of Option A, known as Option A+, as its preferred alternative.

The workgroup also proposed financing the 520 renovations by tolling the existing 520 bridge beginning in the spring of 2011, charging solo drivers to use express lanes on the Interstate 90 bridge, and applying for federal and state grants.

House Speaker Frank Chopp, a member of the panel, opposes Option A+, citing concerns about lack of mitigation for communities affected by the plan and doubts about how a new drawbridge might impact transit traffic moving to to the University of Washington light-rail station.

Supporters of the plan say it meets the budget and timeline while risking few permitting hurdles.

King County Metro Transit has given its blessing to Option A+ despite the fears about traffic impacts.

The supplemental draft environmental-impact statement reports that the all of the proposed interchange plans would reduce HOV travel times by 40 minutes during peak hours and treat stormwater before it reaches Lake Washington.

Each of the options would also provide a 14-foot-wide regional path for bicyclists and pedestrians.

WSDOT will take public comments on the supplemental draft environmental-impact statement until March 8.

A hearing and open house will take place Feb. 23 from 5-7 p.m. at the Lake Union Naval Reserve Building in Seattle (860 Tery Ave. N).

For more information, visit the 520 bridge project web site or call 206-770-3500.