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I-5 - SR 16 Realignment - HOV Structure and Connections

Status: planning
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Project vicinity in Tacoma. View entire map.

Nalley Valley in 2013
I-5/SR 16 Nalley Valley interchange in 2014, after both the Westbound and Eastbound jobs are complete.

Nalley Valley Interchange complete
Nalley Valley interchange in 2022. The final connections are complete between HOV lanes on I-5 and SR 16. The enhanced photo enlargement (pdf 1.5 MB) labels the roadways to show how traffic will move between I-5 and SR 16.


March 2015

  • The I-5/State Route 16 Eastbound Nalley Valley project reached its last major milestone on Aug. 2014 when two new ramps from South Sprague Avenue to northbound and southbound Interstate 5. The first half of the "Sprague T" opened to traffic in June 2011.
  • This page discusses the third and final project to improve the I-5/SR 16 interchange. The third project will build an HOV facility through the Nalley Valley and direct-connect HOV ramps between HOV lanes on I-5 and HOV lanes on SR 16.
  • This project will use the design-build method of project delivery. The timeframe for design and construction is between 2016 and 2019.

Why is WSDOT building HOV roadways and HOV direct-access ramps as part of a newly-expanded I-5/SR 16 Nalley Valley interchange? 
To increase safety, improve mobility and reduce congestion, WSDOT is rebuilding the entire I-5/SR 16 Nalley Valley interchange. The original Nalley Valley interchange was too narrow to carry additional lanes and the unique structure-type prevented widening.

Reconstruction of the interchange is staged to keep people and goods moving. The first two stages of work rebuilt the westbound and eastbound Nalley Valley viaduct bridges. This last stage could not be built until the other two were complete. 

The new westbound viaduct and associated westbound ramps opened to traffic in June, 2011.  Eastbound construction reached its last major milestone August, 2014 when crews opened two new ramps from South Sprague Avenue to northbound and southbound Interstate 5. 
In the third project, not only will WSDOT build new HOV bridges and ramps, crews will also rebuild and realign northbound and southbound I-5 approaching SR 16. 

This project is one of several that make up a larger program to reduce congestion, improve safety and add HOV lanes in Pierce County. Learn more about the overall Tacoma/Pierce County HOV Program.

The End Result
The HOV Connector project will build new bridge structures and direct-access ramps to connect I-5 HOV lanes to SR 16 HOV lanes. These structures will be limited solely to HOV traffic, and will create the last HOV link within a core HOV system that will stretch from Gig Harbor to Everett. A significant amount of construction will also occur on northbound and southbound I-5 while crews realign it for better traffic flow.

Project Benefits
The HOV Connector project has numerous benefits, including:

Traffic Operations

  • Builds direct-access HOV ramps connecting I-5 HOV lanes with SR 16 HOV lanes
  • Adds capacity and improves traffic flow
  • Reduces conflicting movements and weaving areas


  • Improves stormwater treatment


  • Widens shoulders
  • Improves lighting
  • Improves ramp alignments and curves

What is the project timeline?
2016 - Design work to begin

2018 - Construction to begin

2020 - Construction ends; HOV facilities at I-5/SR 16 interchange open to traffic.

This project and two more in the Tacoma/Pierce County HOV Program completely rebuild the Nalley Valley interchange.  Those projects and more make up the entire Tacoma/Pierce County HOV Program.  Learn more!

Financial Information

Financial Data for PIN 300566A
Funding Source Amount ($ in thousands)
2003 Gas Tax (Nickel Funding) $0
2005 Gas Tax (TPA) $215,580
Pre-Existing Funds (PEF) $1,760
Total $217,339

Project signage will reflect the cost of construction engineering, project bid award and sales tax.

How can I get more information?

John Wynands
Asst. Region Administrator for Project Development

Claudia Bingham Baker
Communications Manager
WSDOT Olympic Region
5720 Capitol Boulevard SE
Tumwater, WA 98501

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