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Saturday, September 26, 2020

Lake Forest Park Town Center – Burke-Gilman Trail Connector: Overpass or Underpass?

Option A Mid-block crossing approximately where the current Bank of America building sits.
Viewed from the south at Town Center
V+M Structural Design


By Tracy Furutani

How should pedestrians and non-motorized vehicles get from the Burke-Gilman trail to the Town Center and the proposed Bus Rapid Transit (BRT) garage and stops?

Three preliminary options, two of which involve an overpass across Bothell Way (State Route 522) and the other an underpass, were presented to the Lake Forest Park City Council Thursday night.

“This project has a lot of constraints on it, “ said Schaun Valdovinos, the president and principal engineer of V+M Structural Design, the firm hired by the city to perform the preliminary design, funded by a state Department of Commerce grant.

The constraints include Lyon Creek, which parallels Bothell Way in the project area, a patchwork of privately-owned parcels and buildings on either side of the roadway, and overhead power lines and buried fiber optic cables. 

Option B Overpass - viewed from the north
V+M Structural Design


Three alignment options for the crossing were investigated, he said:

  1. “mid-block” overpass (Option A) approximately where the current Bank of America building sits, 
  2. overpass (Option B)
  3. underpass (Option C) on the south side of the intersection of Ballinger Way and Bothell Way.

Councilmember John Wright raised the point of an underpass’s effect on the Lake Forest Park aquifer, and Councilmember Semra Riddle pointed out some seismic safety and traffic disruption concerns.

Councilmembers Tom French and Lorri Bodi both wondered if any of the options would be used by people crossing Bothell Way, rather than those people continuing to use the existing level crossings.

The cost of the construction of the crossing, which has not been funded, would be least for the mid-block overpass, according to Valdovinos.

Option C underpass on the south side of the intersection of Ballinger Way and Bothell Way
Viewed from the north on the Burke-Gilman trail
V+M Structural Design


The overpass at the intersection would be more expensive because of the need for an elevator for accessibility on the east side.

The underpass would be still more expensive because of the high water table in the area and the need for continuous pumping.

The mid-block overpass would have the least impact on the trees lining Bothell Way.

“This is preliminary design work to understand all the constraints of our future project and that we’re not presuming at this point that other property owners would concur or enter into any agreement that involves their property,” said Donnelle Dayao, Project Manager for the city.


The next step in the project is the December presentation of the Type, Size and Location (TS&L) report, which will contain information such as recommendations and numerical cost estimates.




5 comments:

  1. If this project comes to fruition, I hope you'll have actual disabled people involved in & providing input during the design phase... beyond the proposed elevator for the Option B overpass. Accessibility that's dependant on electricity to operate will essentially render the crossing inaccessible to disabled people for considerable periods of time. Especially given how often the power goes out in the area during fall & winter (and less often, the other seasons). Thank you.

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  2. Has the case been made that an overpass or underpass is actually necessary? Why not wait and see. There isn't any funding. Overpasses are often ugly.The use of street level crosswalks works now. Possibly a scramble system would improve traffic flow. The scramble system allows pedestrians and bicycles to go in any direction needed. Diagonal crossings make sense. A spendy overpass or underpass not so much.

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  3. The mid-block overpass option looks good. Much better than the tunnel.

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  4. Option A would have the least environmental impact and will accommodate the greatest number of people, including disabled, and will have minimal impact on traffic, now and for decades to come. The cost differential between the three options is not a consideration. Richard

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  5. I'd like to see improved at-grade crossings and better pathways connecting them to the business areas. Seems like most folks will continue using them. If something new is being built, the bridge seems far less problematic than the tunnel.

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