WSDoT is creative in widening I-90 through Snoqualmie Pass:
https://maps.app.goo.gl/j6PCCtLFucEFCWga8?g_st=ic
(Related article:
https://www.enr.com/articles/50734-enr-n...r-i-90snowshed-to-keechelus-dam-phase-1c)
Here, the widening requires replacing the snowshed with a viaduct:
https://maps.app.goo.gl/jNENCG3gmaiMJLHi6?g_st=ic
(Related article:
https://highways.dot.gov/public-roads/julaug-2009/reconstructing-snoqualmie-pass)
This project may provide clues on twinning TCH through the Three Valley Gap (i.e. putting EB lanes on a higher ground with retaining walls) and through the snowsheds in National Parks (i.e. replacing the snow shed with a bridge).
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