Commission hears transport project updates including $47M tunnel estimate for Thorpe Road study

Summary

Staff told the Plan Commission that WSDOT is moving the Liberty Park land bridge into the design phase and that a Thorpe Road tunnel option was studied; a tunnel option was estimated at about $47,000,000 and would require long closures if the existing tunnel were enlarged. Commissioners asked for more detail on alternatives and project sequencing.

In the meeting’s updates, staff reported that WSDOT is advancing the design phase for the Liberty Park land bridge and that consultants had completed a Thorpe Road study evaluating two tunnel options and bridge alternatives.

A staff speaker summarized the Thorpe Road study and said project work considered whether to enlarge the existing tunnel (which would require extended closures) or build a new tunnel to the north or south; staff cited a proposed tunnel price of about $47,000,000 for one of the options and said that enlarging the existing tunnel would be $8–9 million more expensive and would require one to two years of closure for mitigation. BNSF reviewed the plan and had no issues reported in the meeting.

Commissioners asked whether bridging over the tracks had been considered and requested additional cost and access information for public review. Staff said preliminary designs and an alternatives matrix will be available as the projects proceed to preliminary design.