TACOMA – With 11 years and three construction projects in the rear-view mirror, the task of adding much needed capacity to the Nalley Valley Viaduct – a massive interchange connecting Interstate 5 and State Route 16 in Tacoma – is nearing completion.
This month, Washington State Department of Transportation’s contractor Skanska will open connected high-occupancy-vehicle (HOV) lanes between the two highways, marking the end to the third and final project that rebuilt the interchange.
“We are thrilled to have HOV lanes on this vital interchange open to travelers,” said WSDOT Regional Administrator John Wynands. “They are a key transportation component that keeps people moving, and improves trip reliability for those who choose to share the ride. At the end of the day, that is what this project is all about.”
Once open, vanpools, carpools, school buses and other vehicles carrying two or more people can use dedicated HOV lanes between SR 16 and I-5. WSDOT created a video that shows travelers how those connections will work.
The contractor plans to have the connecting HOV lanes open between I-5 and SR 16 by mid-November.
HOV lanes under construction across Puyallup River
While opening the HOV connections at the I-5 and SR 16 interchange is a milestone, there is still one final piece of the Tacoma/Pierce County HOV puzzle currently under construction.
The I-5 Portland Avenue to Port of Tacoma Road Southbound HOV project not only builds a new southbound I-5 Puyallup River bridge, it also builds the connecting HOV lanes between Tacoma and Fife.
When the HOV connections open at the I-5 and SR 16 interchange, travelers who use the northbound I-5 HOV lane will temporarily merge into mainline traffic near the Yakima Avenue overpass. This temporary configuration will remain in place until the southbound I-5 Puyallup River Bridge project is complete, in late 2021. At that time, the entire HOV system will be open, with HOV lanes extending from Gig Harbor on SR 16, onto I-5 through Tacoma and Fife and continuing through King County.
During the past 20 years, the Tacoma/Pierce County HOV Program has built of a series of projects on I-5 and SR 16, each building the foundation for the next. In total, the program represents a $1.6 billion investment in the highway infrastructure that increases capacity with new HOV facilities, and rebuilds I-5 through Tacoma.
History of the Nalley Valley Viaduct
- Original Nalley Valley Viaduct opened in 1971, with a daily average of 40,000 vehicles using the interchange.
- By 2019, that number more than tripled to a daily average of 133,000 vehicles.
- In 2008, design and construction efforts began to bring additional capacity to viaduct through three separate projects spanning 11 years:
- SR 16 Westbound Nalley Valley project, completed in 2011
- SR 16 Eastbound Nalley Valley project, completed in 2014
- I-5 – SR 16 Realignment – HOV Structure and Connections, completed fall 2019