a Strategic Highway Network corridor, connecting Naval Base Kitsap to the state highway system along with SR 3, within the National Highway System that classifies it as important to the national economy, defense, and mobility. WSDOT designates the entire route of SR 16 as a Highway of Statewide Significance, which includes highways that connect major communities in the state of Washington. History The present route of SR 16 roughly follows the route of several state highways signed during the 20th century, the first of which was State Road 14. State Road 14 traveled north from Shelton to Gorst and south into Gig Harbor as the primary connector between the Olympic and Kitsap peninsulas. Its construction had been proposed by Pierce County in the 1910s to connect Gig Harbor to the Navy Yard Highway, which was under construction at the time. State Road 14 was re-designated in 1937 as PSH 14 and included a secondary highway named SSH 14C that traveled from Gig Harbor to the Tacoma Narrows, site of an under-construction suspension bridge to open in 1940. PSH 14 was extended southeast over SSH 14C and the unfinished Tacoma Narrows Bridge into the city of Tacoma as part of a transfer of bridge ownership to the state of Washington in 1939. After the collapse of the original bridge on November 7, 1940, PSH 14 was truncated to Gig Harbor and traffic was redirected to a ferry landing in Manchester. The second Tacoma Narrows Bridge was opened on October 14, 1950, and PSH 14 was extended the following year to an intersection with U.S. Route 99 (US 99) in Downtown Tacoma. PSH 14 was replaced by SR 16 under the sign route system created during the 1964 state highway renumbering, traveling from US 99 in Tacoma to SR 3 in Gorst. WSDOT began converting the SR 16 corridor to a controlled-access freeway with the construction of the Nalley Valley Viaduct in 1969, designed with tetrapod columns at a cost of $3.67 million. The viaduct opened on October 29, 1971, and connected SR 16 to I-5 in Tacoma, part of a new freeway replacing Bantz Boulevard between I-5 and the Tacoma Narrows Bridge. A bypass of Purdy on the Pierce–Kitsap county line was opened in November 1978 and the former route of SR 16 was divided between SR 302 and its spur route. The remainder of SR 16 in Port Orchard was