WSDOT will build this project in phases.
Phase 1
With the existing $112 million from the 2003 Nickel Package and the 2005 Transportation Package WSDOT will eliminate the weave problem on southbound and northbound I-5 between the SR 18 ramps by constructing two flyover ramps. These funds will also be used to rebuild the ramp connections from SR 18 to I-5 so they accommodate the new flyover ramps and to purchase right-of-way for future improvements.
Phase 2
This phase includes adding new collector distributor lanes to I-5 and the construction of two new exits from I-5 to SR 161. These exits, at S. 356th street and S. 359th street, will reduce dependency on the S. 348th and SR 161 intersection allowing traffic to move more efficiently through this heavily congested intersection. This phase is currently unfunded.
Phase 3
Further improvements to this intersection focus on lengthening merges and improving freeway efficiency. Current estimates for these improvements range from $50 - $70 million.