Before being designated Secondary State Highway 1G (SSH 1G) in 1937, the current roadway that is now SR 538 was a county road through farmland for 26 years. SSH 1G traveled between Primary State Highway 1 (PSH 1), also known as US 99, and SSH 1A until 1964, when the current designation of SR 538 was created. US 99 was bypassed by I-5 after 1966 and became Riverside Drive. The roundabout at SR 9 was constructed in 2007 while the Riverside Drive intersection was widened in 2009.
Route description
State Route 538 (SR 538) begins at the Interstate 5 (I-5) interchange in northern Mount Vernon located south of the Skagit River.[3] The roadway, which handled a daily average of 27,000 motorists at the interchange in 2008,[4] is named College Way and travels east through a commercial zone, passing Riverside Drive, the former route of U.S. Route 99 (US 99),[5] and crossing a set of rail tracks used by BNSF Railway.[6] Transitioning from a commercial to residential area, the Mount Vernon campus of the Skagit Valley College, located on the north side of the highway, is passed and eventually SR 538 leaves Mount Vernon city limits.[1][7][8] The road turns southeast and ends at a roundabout with SR 9 within Mount Vernon's urban growth boundary.[9][10]
In early 2009, between I-5 and 18th Street, WSDOT repaved the highway and expanded the Riverside Drive intersection.[19][20] A city-led project to widen the section of College Way that passes under I-5 at the western terminus of SR 538 began construction in December 2018 and was completed in 2020. The street was expanded to six lanes, including dedicated left turn lanes and two through lanes that are separated from the rest of traffic by the columns of the underpass.[21]
^Washington State Department of Transportation (2008). "2008 Annual Traffic Report"(PDF). Archived from the original(PDF) on June 16, 2010. Retrieved October 3, 2009.
^Washington State Legislature (March 18, 1937). "Chapter 207: Classification of Public Highways". Session Laws of the State of Washington (1937 ed.). Olympia, Washington: Washington State Legislature. p. 935. Retrieved October 3, 2009. (g) Secondary State Highway No. 1G; beginning at Mt. Vernon on Primary State Highway No. 1, thence in an easterly direction by the most feasible route to a junction with Secondary State Highway No. 1A.
^Washington State Department of Transportation (2009). "SR 536/SR 538 – Paving". Archived from the original on October 7, 2012. Retrieved October 3, 2009.