520 Bridge – Proposed Pacific Interchange

Notes: Presentation to UW Senate.
The Washington State Department of Transportation (WashDOT) will release the SR
520 project Environmental Impact Statement (EIS) mid-summer. Because
there is only a 60-day comment period, this meeting is the last
opportunity for the Senate to hear about the
proposed expansion of SR 520.

WashDOT is evaluating a six lane alternative, which would add two dedicated HOV lanes. The Pacific Street Interchange — which was part of a proposal by — has gained traction with WashDOT as an addition/change to the original six lane proposal. Arial View.

This Pacific Street Interchange would result in the closure of the current Montlake exit/onramp at Shelby-Hamlin.  WashDOT would build a new offramp that terminates in the Husky Stadium Parking Lot. [Note: WashDot has rejected the suspension bridge portion of the Better Bridge proposal.]

These links show WashDOT’s latest interpretation of the Pacific Street
Interchange. (very large,
cropped) Note the "lid" over the interchange, which appears to be
larger than Husky Stadium football field.
The offramp is eight lanes; Montlake would be six lanes north to 45th.

This proposal:

  1. Has a negative impact on the Washington Park Arboretum.
  2. Increases traffic volumes on neighborhood streets around the
  3. Has a significant and negative impact on the long term development capacity of
    the University.

This proposal for a new interchange would shift
the "externality" of living near an off-ramp from the Shelby/Hamlin
area to the Montlake/Pacific-45th area as well as to those living
around the Lake Washington Blvd/Arboretum exit. In
addition, WashDOT data suggest that by widening Montlake, the proposal
will result in increased SOV traffic from Pacific to 45th.

So there are two impacts: an increase in total traffic on North
Montlake and a shifting of an externality to other neighborhoods.

the Shelby/Hamlin off-ramp was (probably) present when current
landowners purchased their homes; their property values should have
reflected this externality and thus would be positively impacted should
this proposal move forward. Homeowners in other neighborhoods who would
be affected by this proposal, but who did not purchase their property
knowing of this externality, will have their property values negatively

WashDOT Data:

  • 30% increase in traffic on SE campus streets
  • 49% increase in traffic at Lake Wash Blvd exit off 520, with 12% going
    around the Arboretum and 37% going thru Montlake neighborhood (on two-lane non-arterials) to get to
  • 49% decrease in traffic across Montlake at Shelby and Hamlin

On Monday, the Faculty Council on University Relations met with
Theresa Doherty, Assistant Vice President for Regional Affairs, to find
out more about the SR 520 Replacement Project and its relationship to
the Sound Transit tunnel/station project. The Council believes that
faculty need to be made aware of the concerns surrounding the Pacific
Street Interchange, not just for the University but also for the neighborhoods surrounding the University.

Concerned faculty should write President Emmert, the Washington
State Department of Transportation, and Governor Gregoire. Watch the
WashDOT site for public meetings and comment on the EIS.


Updated with resource links and additional details at 5.50pm.

By Kathy E. Gill

Digital evangelist, speaker, writer, educator. Transplanted Southerner; teach newbies to ride motorcycles! @kegill

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