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I-5 Tumwater to Mounts Road Corridor Planning and Environmental Linkages Study – Interchange Strategies Moving Forward

Maps and figures are conceptual and not to scale.

Map legend
Strategy #StrategyDescriptionMilepost
Int 2Martin Way InterchangePartial cloverleaf interchange.109.0-109.6
Int 4US 101 Interchange revision with braided on rampsConstruct braided ramp between southbound I-5 and US 101, replace existing bridge on southbound I-5 to 14th, and install new bridge for on-ramp over Henderson. Exit at Plum Street to access braided ramp SB I-5 and add an auxiliary lane between Pacific Ave and Capitol Way104.7-105.7

Int 2: Martin Way Interchange

  • Partial cloverleaf interchange
  • Recommended to move forward due to improved volume and throughput on I-5.
Two side-by-side aerial photos of an intersection show proposed improvements to include adding cloverleaf ramps at both the northbound and southbound approaches to Interstate 5 from Martin Way
Left: Existing. Right: Improvement. Image from Thurston Regional Planning Council.

Int 4: US 101 Interchange revision with braided on-ramps

  • Construct braided ramp between southbound I-5 and US 101, replace existing bridge on southbound I-5 to 14th Avenue Southeast, and install new bridge for on-ramp over Henderson Boulevard Southeast. Exit at Plum Street to access braided ramp SB I-5 and add an auxiliary lane between Pacific Avenue and Capitol Way.
  • Recommended to move forward for further analysis due to potential benefits to speed on I-5 southbound. Recommend considering signage and redesign of Plum Street exit.
Two side-by-side aerial photos of an intersection show proposed improvements to include constructing a braided ramp between southbound I-5 and US 101, replacing existing bridge on southbound I-5 to 14th, and installing a new bridge for on-ramp over Henderson Boulevard Southeast. Exit at Plum Street to access braided ramp SB I-5 and add an auxiliary lane between Pacific Ave and Capitol Way.
Left: Existing. Right: Improvement. Image from Thurston Regional Planning Council