Overview 
This project series improves a total of seven miles of I-5 between Mellen Street (Exit 81) in Lewis County and just south of the Grand Mound interchange (Exit 88) in Thurston County.

The I-5 Mellen Street to Grand Mound Project will be constructed in two separate stages:

I-5, Blakeslee Junction to Grand Mound
This project widened four miles of I-5 from two to three lanes in each direction between the Blakeslee railroad junction in Lewis County (milepost 83.5) and just south of the Grand Mound interchange (Exit 88) in Thurston County. Construction began in June 2010, the new lanes were open to traffic in November 2011, and the project was complete in February 2013.

I-5, Mellen Street to Blakeslee Junction
This project improves safety and mobility for all vehicles traveling on this section of I-5 by constructing Collector Distributor (CD) lanes (pdf 141 kb) between Mellen Street and Harrison Avenue, improving the Mellen Street interchange and re-aligning and straightening I-5 at Blakeslee curve.

Why is WSDOT building this project?
I-5 is the most significant freight freeway on the West Coast. The interstate links markets in Canada, the United States and Mexico, and is critical to the regional, state and national economy.

WSDOT is investing $390 million from the 2003 and 2005 gas-tax packages in four projects – including this project series – to improve traffic flow and safety along 18 miles of I-5 in Lewis and Thurston counties. By widening and improving the interstate corridor, these projects will help reduce congestion, improve traffic flow and reduce the chance for collisions caused by traffic backups and merging conditions.

The End Result

• I-5, Blakeslee Junction to Grand Mound (complete in 2012): I-5 between Blakeslee Junction in Lewis County and just south of the Grand Mound interchange (Exit 88) in Thurston County is now barrier-divided with three general-purpose lanes in each direction.
• I-5 - Mellen Street to Blakeslee Junction: Collector Distributor lanes on the outside of mainline I-5 will relieve congestion between Mellen Street and Blakeslee Junction, and a new bridge over I-5 will help regulate traffic flow at the Mellen Street interchange. 

Project Benefits

• Mobility: Increases the interstate’s capacity and traffic flow through Lewis County by improving approximately seven miles of I-5 between the Mellen Street interchange (Exit 81, Lewis County) and just south of the Grand Mound interchange (Exit 88, Thurston County). 
• Safety: Helps reduce the chance for collisions that commonly occur in traffic backups and merging conditions.
• Economic: Improves freight and commuter mobility through Lewis County.

What is the project timeline?

• Stage 2 of I-5 - Mellen to Blakeslee Junction was awarded to Scarsella Bros., Inc. of Kent, WA in June 2013. Construction began in Aug. 2013 and is scheduled for completion in late 2017.
• Stage 1 of I-5 - Mellen to Blakeslee Junction was completed in Aug. 2013.

Funding
2005 Gas Tax (TPA): $152,056,000
Pre-Existing Funds (PEF): $881,000
Total: $152,938,000